- Ruckerbactin Produced by Yersinia ruckeri YRB Is a Diastereomer of the Siderophore Trivanchrobactin Produced by Vibrio campbellii DS40M4
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The Gram-negative bacterium Yersinia ruckeri is the causative agent for enteric red mouth disease in salmonids. The genome of Y. ruckeri YRB contains a biosynthetic gene cluster encoding the biosynthesis of catechol siderophores that are diastereomeric with the known vanchrobactin class of siderophores, (DHBDArgLSer)(1–3). Ruckerbactin (1), produced by Y. ruckeri YRB, was found to be the linear tris-l-serine ester composed of l-arginine and 2,3-dihydroxybenzoic acid, (DHBLArgLSer)3. The biscatechol, (DHBLArgLSer)2 (2), and monocatechol, DHBLArgLSer (3), compounds were also isolated and characterized. The macrolactone of ruckerbactin was not detected. The presence of LArg in ruckerbactin makes it the diastereomer of trivanchrobactin with DArg. The electronic circular dichroism spectra of Fe(III)–ruckerbactin and Fe(III)–trivanchrobactin reveal the opposite enantiomeric configurations at the Fe(III) sites. Fe(III)–ruckerbactin adopts the Δ configuration, and Fe(III)–trivanchrobactin adopts the Λ configuration. Y. ruckeri YRB was also found to produce the antimicrobial agent holomycin (4).
- Butler, Alison,Dulaney, Kalana,Reitz, Zachary L.,Stow, Parker R.,Thomsen, Emil
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p. 264 - 269
(2022/01/15)
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- Direct monitoring of biocatalytic deacetylation of amino acid substrates by1H NMR reveals fine details of substrate specificity
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Amino acids are key synthetic building blocks that can be prepared in an enantiopure form by biocatalytic methods. We show that thel-selective ornithine deacetylase ArgE catalyses hydrolysis of a wide-range ofN-acyl-amino acid substrates. This activity was revealed by1H NMR spectroscopy that monitored the appearance of the well resolved signal of the acetate product. Furthermore, the assay was used to probe the subtle structural selectivity of the biocatalyst using a substrate that could adopt different rotameric conformations.
- De Cesare, Silvia,McKenna, Catherine A.,Mulholland, Nicholas,Murray, Lorna,Bella, Juraj,Campopiano, Dominic J.
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supporting information
p. 4904 - 4909
(2021/06/16)
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- Targeted Isolation of Asperheptatides from a Coral-Derived Fungus Using LC-MS/MS-Based Molecular Networking and Antitubercular Activities of Modified Cinnamate Derivatives
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Under the guidance of MS/MS-based molecular networking, four new cycloheptapeptides, namely, asperheptatides A-D (1-4), were isolated together with three known analogues, asperversiamide A-C (5-7), from the coral-derived fungus Aspergillus versicolor. The planar structures of the two major compounds, asperheptatides A and B (1 and 2), were determined by comprehensive spectroscopic data analysis. The absolute configurations of the amino acid residues were determined by advanced Marfey's method. The two structurally related trace metabolites, asperheptatides C and D (3 and 4), were characterized by ESI-MS/MS fragmentation methods. A series of new derivatives (8-26) of asperversiamide A (5) were semisynthesized. The antitubercular activities of 1, 2, and 5-26 against Mycobacterium tuberculosis H37Ra were also evaluated. Compounds 9, 13, 23, and 24 showed moderate activities with MIC values of 12.5 μM, representing a potential new class of antitubercular agents.
- Chao, Rong,Hou, Xue-Mei,Xu, Wei-Feng,Hai, Yang,Wei, Mei-Yan,Wang, Chang-Yun,Gu, Yu-Cheng,Shao, Chang-Lun
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- Structures and Biosynthetic Pathway of Coprisamides C and D, 2-Alkenylcinnamic Acid-Containing Peptides from the Gut Bacterium of the Carrion Beetle Silpha perforata
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Coprisamides C and D (1 and 2) were isolated from a gut bacterium, Micromonospora sp. UTJ3, of the carrion beetle Silpha perforata. Based on the combined analysis of UV, MS, and NMR spectral data, the planar structures of 1 and 2 were elucidated to be unreported derivatives of coprisamides A and B, cyclic depsipeptides bearing a 2-alkenylcinnamic acid unit and the unusual amino acids β-methylaspartic acid and 2,3-diaminopropanoic acid. The absolute configuration of 1 was determined using the advanced Marfey's method, phenylglycine methyl ester derivatization, and J-based configuration analysis. The biosynthetic gene clusters for the coprisamides were investigated based on genomic data from coprisamide-producing strains Micromonospora sp. UTJ3 and Streptomyces sp. SNU533. Coprisamide C (1) was active against the Mycobacterium tuberculosis mc26230 strain.
- Shin, Yern-Hyerk,Ban, Yeon Hee,Kim, Tae Ho,Bae, Eun Seo,Shin, Jongheon,Lee, Sang Kook,Jang, Jichan,Yoon, Yeo Joon,Oh, Dong-Chan
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- Leveraging Peptaibol Biosynthetic Promiscuity for Next-Generation Antiplasmodial Therapeutics
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Malaria remains a worldwide threat, afflicting over 200 million people each year. The emergence of drug resistance against existing therapeutics threatens to destabilize global efforts aimed at controlling Plasmodium spp. parasites, which is expected to leave vast portions of humanity unprotected against the disease. To address this need, systematic testing of a fungal natural product extract library assembled through the University of Oklahoma Citizen Science Soil Collection Program has generated an initial set of bioactive extracts that exhibit potent antiplasmodial activity (EC50 25 μM, selectivity index > 250). The unique chemodiversity afforded by these fungal isolates serves to unlock new opportunities for translating peptaibols into a bioactive scaffold worthy of further development.
- Lee, Jin Woo,Collins, Jennifer E.,Wendt, Karen L.,Chakrabarti, Debopam,Cichewicz, Robert H.
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supporting information
p. 503 - 517
(2021/03/01)
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- Saccharochelins A-H, Cytotoxic Amphiphilic Siderophores from the Rare Marine Actinomycete Saccharothrix sp. D09
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Siderophores are secreted by microorganisms to survive in iron-depleted conditions, and they also possess tremendous therapeutic potential. Genomic-inspired isolation facilitated the identification of eight amphiphilic siderophores, saccharochelins A-H (1-8), from a rare marine-derived Saccharothrix species. Saccharochelins feature a series of fatty acyl groups appended to the same tetrapeptide skeleton. With the help of gene disruption and heterologous expression, we identified the saccharochelin biosynthetic pathway. The diversity of saccharochelins originates from the flexible specificity of the starter condensation (CS) domain at the beginning of the nonribosomal peptide synthetase (NRPS) toward various fatty acyl substrates. Saccharochelins showed cytotoxicity against several human tumor cell lines, with IC50 values ranging from 2.3 to 17 μM. Additionally, the fatty acid side chains of the saccharochelins remarkably affected the cytotoxicity, suggesting changing the N-terminal acyl groups of lipopeptides may be a promising approach to produce more potent derivatives.
- Bian, Xiaoying,Dai, Guangzhi,Jiao, Nianzhi,Liu, Yang,Ravichandran, Vinothkannan,Ren, Xiangmei,Shen, Qiyao,Sui, Haiyan,Zhang, Youming,Zhong, Lin,Zhou, Haibo
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p. 2149 - 2156
(2021/08/20)
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- Pagoamide A, a Cyclic Depsipeptide Isolated from a Cultured Marine Chlorophyte, Derbesia sp., Using MS/MS-Based Molecular Networking
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A thiazole-containing cyclic depsipeptide with 11 amino acid residues, named pagoamide A (1), was isolated from laboratory cultures of a marine Chlorophyte, Derbesia sp. This green algal sample was collected from America Samoa, and pagoamide A was isolated using guidance by MS/MS-based molecular networking. Cultures were grown in a light- and temperature-controlled environment and harvested after several months of growth. The planar structure of pagoamide A (1) was characterized by detailed 1D and 2D NMR experiments along with MS and UV analysis. The absolute configurations of its amino acid residues were determined by advanced Marfey's analysis following chemical hydrolysis and hydrazinolysis reactions. Two of the residues in pagoamide A (1), phenylalanine and serine, each occurred twice in the molecule, once in the d- and once in the l-configuration. The biosynthetic origin of pagoamide A (1) was considered in light of other natural products investigations with coenocytic green algae.
- Cottrell, Garrison W.,Fang, Fang,Gerwick, Lena,Gerwick, William H.,Glukhov, Evgenia,Guan, Huashi,Kim, Hyunwoo,Leao, Tiago,Li, Yueying,Mao, Huanru Henry,Murray, Thomas F.,Pierce, Marsha L.,Yu, Hao-Bing,Zhang, Chen,Zhang, Yi
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supporting information
(2020/01/31)
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- Hydrogen Bond Assisted l to d Conversion of α-Amino Acids
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l to d conversion of unactivated α-amino acids was achieved by solubility-induced diastereomer transformation (SIDT). Ternary complexes of an α-amino acid with 3,5-dichlorosalicylaldehyde and a chiral guanidine (derived from corresponding chiral vicinal diamine) were obtained in good yield as diastereomerically pure imino acid salt complexes and were hydrolysed to obtain enantiopure α-amino acids. A combination of DFT computation, NMR spectroscopy, and crystal structure provide detailed insight into how two types of strong hydrogen bonds assist in rapid epimerization of the complexes that is essential for SIDT.
- Chin, Jik,Fu, Rui,Lough, Alan J.,So, Soon Mog
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supporting information
p. 4335 - 4339
(2020/02/11)
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- D -Serine as a Key Building Block: Enzymatic Process Development and Smart Applications within the Cascade Enzymatic Concept
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An efficient enzymatic method catalyzed by an enzyme from the d-threonine aldolase (DTA) family was developed for d-serine production at industrial scale. This process was used for the synthesis of two valuable ketoses, l-erythrulose and d-fructose, within the cascade enzymatic concept involving two other enzymes. Indeed, d-serine was used as a substrate of d-amino acid oxidase (DAAO) for the in situ generation of the corresponding α-keto acid, hydroxypyruvic acid (HPA), a key donor substrate of transketolase (TK). This enzyme catalyzed the irreversible transfer of the ketol group from HPA to an aldehyde acceptor to form a (3S)-ketose by stereoselective carbon-carbon bond formation. The compatibility of all enzymes and substrates allowed a sequential three-step enzymatic process to be performed without purification of the intermediates. This strategy was validated with two TK aldehyde substrates to finally obtain the corresponding (3S)-ketoses with high control of the stereoselectivity and excellent aldehyde conversion rates.
- Auffray, Pascal,Charmantray, Franck,Collin, Jér?me,Hecquet, Laurence,L'Enfant, Mélanie,Martin, Juliette,Ocal, Nazim,Pollegioni, Loredano
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p. 769 - 775
(2020/07/14)
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- Stalobacin: Discovery of Novel Lipopeptide Antibiotics with Potent Antibacterial Activity against Multidrug-Resistant Bacteria
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A novel lipopeptide antibiotic, stalobacin I (1), was discovered from a culture broth of an unidentified Gram-negative bacterium. Stalobacin I (1) had a unique chemical architecture composed of an upper and a lower half peptide sequence, which were linked via a hemiaminal methylene moiety. The sequence of 1 contained an unusual amino acid, carnosadine, 3,4-dihydroxyariginine, 3-hydroxyisoleucine, and 3-hydroxyaspartic acid, and a novel cyclopropyl fatty acid. The antibacterial activity of 1 against a broad range of drug-resistant Gram-positive bacteria was much stronger than those of last resort antibiotics such as vancomycin, linezolid, and telavancin (MIC 0.004-0.016 μg/mL). Furthermore, compound 1 induced a characteristic morphological change in Gram-positive and Gram-negative strains by inflating the bacterial cell body. The absolute configuration of a cyclopropyl amino acid, carnosadine, was determined by the synthetic study of its stereoisomers, which was an essential component for the strong activity of 1.
- Matsui, Kouhei,Matsui, Kouhei,Kan, Yukiko,Kikuchi, Junko,Matsushima, Keisuke,Takemura, Miki,Maki, Hideki,Kozono, Iori,Ueda, Taichi,Minagawa, Kazuyuki
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supporting information
p. 6090 - 6095
(2020/07/10)
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- Krisynomycins, Imipenem Potentiators against Methicillin-Resistant Staphylococcus aureus, Produced by Streptomyces canus
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A reinvestigation of the acetone extract of the strain CA-091830 of Streptomyces canus, producer of the imipenem potentiator krisynomycin, resulted in the isolation of two additional analogues, krisynomycins B (1) and C (2), with different chlorination patterns. Genome sequencing of the strain followed by detailed bioinformatics analysis led to the identification of the corresponding biosynthetic gene cluster (BGC) of this cyclic nonribosomal peptide family. The planar structure of the new molecules was determined using HRMS, ESI-qTOF-MS/MS, and 1D and 2D NMR data. Their absolute configuration was proposed using a combination of Marfey's and bioinformatic BGC analyses. The krisynomycins displayed weak to negligible antibiotic activity against methicillin-resistant Staphylococcus aureus (MRSA), which was significantly enhanced when tested in combination with sublethal concentrations of imipenem. The halogenation pattern plays a key role in the antimicrobial activity and imipenem-potentiating effects of the compounds, with molecules having a higher number of chlorine atoms potentiating the effect of imipenem at lower doses.
- De La Cruz, Mercedes,Genilloud, Olga,González, Ignacio,Martín, Jesús,Oves-Costales, Daniel,Pérez-Bonilla, Mercedes,Reyes, Fernando,Vicente, Francisca
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p. 2597 - 2606
(2020/10/12)
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- Structure-guided engineering of: Pseudomonas dacunhae l-aspartate β-decarboxylase for l-homophenylalanine synthesis
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Structure-guided engineering of Pseudomonas dacunhael-aspartate β-decarboxylase (AspBDC) resulted in a double mutant (R37A/T382G) with remarkable 15400-fold improvement in specific activity reaching 216 mU mg-1, towards the target substrate 3(R)-benzyl-l-aspartate. A novel strategy for enzymatic synthesis of l-homophenylalanine was developed by using the variant as a biocatalyst affording 75% product yield within 12 h. Our results underscore the potential of engineered AspBDC for the biocatalytic synthesis of pharmaceutically relevant and value added unnatural l-amino acids.
- Zhang, Min,Hu, Pengfei,Zheng, Yu-Cong,Zeng, Bu-Bing,Chen, Qi,Zhang, Zhi-Jun,Xu, Jian-He
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p. 13876 - 13879
(2020/11/18)
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- Library Selection with a Randomized Repertoire of (βα)8-Barrel Enzymes Results in Unexpected Induction of Gene Expression
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The potential of the frequently encountered (βα)8-barrel fold to acquire new functions was tested by an approach combining random mutagenesis and selection in vivo. For this purpose, the genes encoding 52 different phosphate-binding (βα)8-barrel proteins were subjected to error-prone PCR and cloned into an expression plasmid. The resulting mixed repertoire was used to transform different auxotrophic Escherichia coli strains, each lacking an enzyme with a phosphate-containing substrate. After plating of the different transformants on minimal medium, growth was observed only for two strains, lacking either the gene for the serine phosphatase SerB or the phosphoserine aminotransferase SerC. The same mutants of the E. coli genes nanE (encoding a putative N-acetylmannosamine-6-phosphate 2-epimerase) and pdxJ (encoding the pyridoxine 5′-phosphate synthase) were responsible for rescuing both ΔserB and ΔserC. Unexpectedly, the complementing NanE and PdxJ variants did not catalyze the SerB or SerC reactions in vitro. Instead, RT-qPCR, RNAseq, and transcriptome analysis showed that they rescue the deletions by enlisting the help of endogenous E. coli enzymes HisB and HisC through exclusive up-regulation of histidine operon transcription. While the promiscuous SerB activity of HisB is well-established, our data indicate that HisC is promiscuous for the SerC reaction, as well. The successful rescue of ΔserB and ΔserC through point mutations and recruitment of additional amino acids in NanE and PdxJ provides another example for the adaptability of the (βα)8-barrel fold.
- Rohweder, Bettina,Lehmann, Gerhard,Eichner, Norbert,Polen, Tino,Rajendran, Chitra,Ruperti, Fabian,Linde, Mona,Treiber, Thomas,Jung, Oona,Dettmer, Katja,Meister, Gunter,Bott, Michael,Gronwald, Wolfram,Sterner, Reinhard
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p. 4207 - 4217
(2019/10/17)
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- Preparation and characterization of a new open-tubular capillary column for enantioseparation by capillary electrochromatography
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In order to use the enantioseparation capability of cationic cyclodextrin and to combine the advantages of capillary electrochromatography (CEC) with open-tubular (OT) column, in this study, a new OT-CEC, coated with cationic cyclodextrin (1-allylimidazolium-β-cyclodextrin [AI-β-CD]) as chiral stationary phase (CSP), was prepared and applied for enantioseparation. Synthesized AI-β-CD was characterized by infrared (IR) spectrometry and mass spectrometry (MS). The preparation conditions for the AI-β-CD-coated column were optimized with the orthogonal experiment design L9(34). The column prepared was characterized by scanning electron microscopy (SEM) and elemental analysis (EA). The results showed that the thickness of stationary phase in the inner surface of the AI-β-CD-coated columns was about 0.2 to 0.5?μm. The AI-β-CD content in stationary phase based on the EA was approximately 2.77?mmol·m?2. The AI-β-CD-coated columns could separate all 14 chiral compounds (histidine, lysine, arginine, glutamate, aspartic acid, cysteine, serine, valine, isoleucine, phenylalanine, salbutamol, atenolol, ibuprofen, and napropamide) successfully in the study and exhibit excellent reproducibility and stability. We propose that the column, coated with AI-β-CD, has a great potential for enantioseparation in OT-CEC.
- Li, Yingjie,Tang, Yimin,Qin, Shili,Li, Xue,Dai, Qiang,Gao, Lidi
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p. 283 - 292
(2019/02/05)
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- Dynamic Kinetic Resolution for Asymmetric Synthesis of L-Noncanonical Amino Acids from D-Ser Using Tryptophan Synthase and Alanine Racemase
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L-Ser is often used to synthesize some significant l-noncanonical α-amino acids(l-ncAAs), which are the prevalent intermediates and precursors for functional synthetic compounds. In this study, threonine aldolase from Escherichia coli k-12 MG1655 has been used to synthesize l-Ser. In contrast to the maximum catalytic capacity (20 g/L) for l-threonine aldolase(LTA), d-Ser was synthesized with high yield (240 g/L) from cheap Gly and paraformaldehyde using d-threonine aldolase (DTA) from Arthrobacter sp ATCC. In order to fully utilize d-Ser and expand the resource of l-Ser, a dynamic kinetic resolution system was constructed to convert d/dl-Ser to l-Ser through combining alanine racemase (Alr) from Bacillus subtilis with l-tryptophan synthase (TrpS) from Escherichia coli k-12 MG1655, and l-ncAAs including l-Trp and l-Cys derivatives were synthesized with excellent enantioselectivity and in high yields. The results indicated l-ncAAs could be efficiently synthesized from d-Ser using this original and green dynamic kinetic resolution system, and the reliable l-Ser resource has been established from simple and achiral substrates.
- Yu, Jinhai,Li, Jing,Gao, Xia,Zeng, Shuiyun,Zhang, Hongjuan,Liu, Junzhong,Jiao, Qingcai
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p. 6618 - 6625
(2019/11/03)
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- Chemical structure of cichorinotoxin, a cyclic lipodepsipeptide that is produced by Pseudomonas cichorii and causes varnish spots on lettuce
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Pseudomonas cichorii, which causes varnish spots on lettuce and seriously damages lettuce production during the summer season in the highland areas of Japan (e.g., Nagano and Iwate prefectures) was isolated. The structure of a toxin produced by this organism was analyzed based on the detailed evaluation of its 2D NMR and FABMS spectra, and this compound has not been reported previously. We propose the name cichorinotoxin for this toxin. In conjunction with the D or L configurations of each amino acid, which were determined by Marfey’s method, we propose the structure of cichorinotoxin to be as follows: 3-hydroxydecanoyl-(Z)-dhThr1-D-Pro2-D-Ala3-D-Ala4-D-Ala5-D-Val6-D-Ala7-(Z)-dhThr8-Ala9-Val10-D-Ile11-Ser12-Ala13-Val14-Ala15-Val16-(Z)-dhThr17-D-alloThr18-Ala19-L-Dab20-Ser21-Val22, and an ester linkage is present between D-alloThr18 and Val22 (dhThr: 2-aminobut-2-enoic acid; Dab: 2,4-diaminobutanoic acid). Thus, the toxin is a lipodepsipeptide with 22 amino acids. The mono- and tetraacetate derivatives and two alkaline hydrolysates, compounds A and B, were prepared. We discuss here the structure–activity relationships between the derivatives and their necrotic activities toward lettuce.
- Komatsu, Hidekazu,Shirakawa, Takashi,Uchiyama, Takeo,Hoshino, Tsutomu
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p. 299 - 309
(2019/02/20)
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- Natural Hydroxamate-Containing Siderophore Acremonpeptides A-D and an Aluminum Complex of Acremonpeptide D from the Marine-Derived Acremonium persicinum SCSIO 115
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Four new hydroxamate-containing natural product cyclopeptides designated acremonpeptides A-D (1-4), together with Al(III)-acremonpeptide D (5) were obtained from the marine fungus Acremonium persicinum SCSIO 115. The planar structures of 1-5 were established on the basis of HRMS as well as 1D and 2D NMR data sets. Moreover, the amino acid absolute configurations were determined using Marfey's method. Compounds 1-5 all feature three 2-amino-5-(N-hydroxyacetamido)pentanoic acid (N5-hydroxy-N5-acetyl-l-ornithine) metal ion chelating moieties. Beyond their discovery and structure elucidation, in vitro bioassays revealed acremonpeptides A (1), B (2), and Al(III)-acremonpeptide D (5) as moderate antiviral agents for herpes simplex virus 1 with EC50 values of 16, 8.7, and 14 μM, respectively.
- Chen, Ziming,Huang, Hongbo,Ju, Jianhua,Luo, Minghe,Song, Xiaoxian,Wang, Xin,Zang, Ruochen
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p. 2594 - 2600
(2019/10/11)
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- Complex-precipitation using functionalized chiral ionic liquids with L-proline anion and chromatographic analysis for enantioseparation of racemic amino acids
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As one kind of functionalized green medium, chiral ionic liquids (CILs) have been widely applied in fields of asymmetric catalysis, enantioseparation, and so on. In this study, four kinds of amino acid–based CILs were synthesized by using trimethylamine, N-methylpyrrolidine, N-methylimidazole, and tropine as cationic nucleus, respectively. Then their specific optical rotation and solubility in common solvents were determined for further resolution application. The effect of different cations in these CILs was explored on the separation of racemic phenylalanine in complex-precipitation way. Moreover, various factors were systematically investigated for their effects on resolution efficiency, including the type of additive copper salts, the molar ratio of Cu (II) to CIL, pH value, the amount of racemic phenylalanine, and temperature. Under the appropriate conditions, L-phenylalanine mainly existed in solid phase and could be separated from its enantiomers in liquid phase. Furthermore, the mechanism of resolution was studied by thermogravimetric analysis, infrared spectrum, and molecular simulation. The resolution system has characteristics of no organic solvent, fast separation speed, simple resolution process, and easy scale-up.
- Zang, Huimin,Yao, Shun,Luo, Yingjie,Tang, Dan,Song, Hang
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p. 1182 - 1194
(2018/09/12)
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- One-Pot Preparation of d-Amino Acids Through Biocatalytic Deracemization Using Alanine Dehydrogenase and Ω-Transaminase
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d-Amino acids are pharmaceutically important building blocks, leading to a great deal of research efforts to develop cost-effective synthetic methods. Preparation of d-amino acids by deracemization has been conceptually attractive owing to facile synthesis of racemic amino acids by Strecker synthesis. Here, we demonstrated biocatalytic deracemization of aliphatic amino acids into d-enantiomers by running cascade reactions; (1) stereoinversion of l-amino acid to a d-form by amino acid dehydrogenase and ω-transaminase and (2) regeneration of NAD+ by NADH oxidase. Under the cascade reaction conditions containing 100?mM isopropylamine and 1?mM NAD+, complete deracemization of 100?mM dl-alanine was achieved after 24?h with 95% reaction yield of d-alanine (> 99% eeD, 52% isolation yield). Graphical Abstract: [Figure not available: see fulltext.].
- Han, Sang-Woo,Shin, Jong-Shik
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p. 3678 - 3684
(2018/10/20)
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- Preparation and purification method of amino acid compound
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The invention relates to the field of industrial organic synthesis, in particular to a preparation and purification method of an amino acid compound. The method comprises the following steps that (1)alpha-amino nitrile compounds or hydantoin compounds or mixtures thereof are heated to react to obtain alpha-amino acid salt under the condition that volatile alkali and a suitable solvent exist; (2)after the alpha-amino acid salt obtained in step (1) is distilled, the alpha-amino acid salt is recrystallized in an organic solvent to obtain the alpha-amino acid compound. According to the method, reaction conditions are mild, materials can be recycled, and introduction of metal ions and use of ammonium carbonate salt are avoided, so that post-treatment is simple and no waste salt is generated.
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-
Paragraph 0058; 0059; 0072; 0073; 0074; 0075
(2018/06/21)
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- A α - amino acid compound synthesis and purification method
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The invention relates to a synthesis and purification method for an alpha-amino acid compound. The synthesis and purification method is characterized by comprising the following steps: (1) adding substituted alpha-amino nitrile or a substituted hydantoin-based compound into alkali M(OH)x or metal oxide MxO, adding water or an alcohol and water mixed solvent, and heating for reaction to obtain alpha-amino acid salt; (2) adding ammonium carbonate or ammonium bicarbonate or introducing carbon dioxide into the solution in the step (1), separating to obtain filter liquor and precipitates MxHyCO3, performing reduced pressure concentration on the filter liquor, and recrystallizing in an alcohol solvent to obtain the alpha-amino acid compound (I). The synthesis and purification method for the alpha-amino acid compound is simple, the yield and purity of the obtained alpha-amino acid compound are high; furthermore, recycling utilization and cleaning production of materials can be realized; the synthesis and purification method is especially suitable for synthesis of the alpha-amino acid compound with high water solubility.
- -
-
Paragraph 0071; 0072; 0074
(2018/05/16)
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- Using the 3-Diethylaminobenzyl Group as a Photocage in Aqueous Solution
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We have demonstrated that the 3-diethylaminobenzyl (DEABn) photolabile protecting group (PPG) is an effective and structurally simple PPG for releasing molecules in aqueous environment. In general, the photoreaction is clean, and the released substrate and the PPG product, i.e., 3-diethylaminobenzyl alcohol, are obtained in high yield. The clean photoreaction can also be achieved under mild ambient conditions with sunlight, while the reactant is stable under indoor lighting. Release of two substrates from one PPG chromophore in aqueous solution has been demonstrated to be feasible. We have also compared the uncaging properties of the DEABn and the widely used o-nitrobenzyl (o-NB) group, given their comparable structural simplicity. With its clean and efficient photochemical reaction, DEABn should find wide applications, including in the basic and applied research areas where o-NB and its various derivatives are widely used.
- Ding, Xiong,Wang, Pengfei
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p. 7459 - 7466
(2018/05/29)
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- Sustainable and Continuous Synthesis of Enantiopure l-Amino Acids by Using a Versatile Immobilised Multienzyme System
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The enzymatic synthesis of α-amino acids is a sustainable and efficient alternative to chemical processes, through which achieving enantiopure products is difficult. To more address this synthesis efficiently, a hierarchical architecture that irreversibly co-immobilises an amino acid dehydrogenase with polyethyleneimine on porous agarose beads has been designed and fabricated. The cationic polymer acts as an irreversible anchoring layer for the formate dehydrogenase. In this architecture, the two enzymes and polymer colocalise across the whole microstructure of the porous carrier. This multifunctional heterogeneous biocatalyst was kinetically characterised and applied to the enantioselective synthesis of a variety of canonical and noncanonical α-amino acids in both discontinuous (batch) and continuous modes. The co-immobilised bienzymatic system conserves more than 50 % of its initial effectiveness after five batch cycles and 8 days of continuous operation. Additionally, the environmental impact of this process has been semiquantitatively calculated and compared with the state of the art.
- Velasco-Lozano, Susana,da Silva, Eunice S.,Llop, Jordi,López-Gallego, Fernando
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p. 395 - 403
(2017/11/13)
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- Fusaristatin C, a Cyclic Lipodepsipeptide from Pithomyces sp. RKDO 1698
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A new cyclic lipodepsipeptide, fusaristatin C (1), was obtained from the fungus Pithomyces sp. RKDO 1698, which was isolated from the Caribbean octocoral Eunicea fusca. The 2D structure of fusaristatin C was elucidated using NMR spectroscopy and mass spectrometry, while the absolute configuration of the sole chiral amino acid residue (l-serine) was determined using Marfey's method. 3-Hydroxy-2,11-dimethyltetradecanoic acid (HDMT) was cleaved from 1, and the absolute configuration at the C-3 position was determined using Mosher's ester analysis. Subsequent J-based configuration analysis of 1 allowed for assignment of the C-2 configuration. Fusaristatin C exhibited no antimicrobial activity or cytotoxicity.
- MacIntyre, Logan W.,Marchbank, Douglas H.,Correa, Hebelin,Kerr, Russell G.
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p. 2768 - 2772
(2019/01/04)
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- Colony-wise Analysis of a Theonella swinhoei Marine Sponge with a Yellow Interior Permitted the Isolation of Theonellamide i
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There are several examples of marine organisms whose metabolic profiles differ among conspecifics inhabiting the same region. We have analyzed the metabolic profile of each colony of a Theonella swinhoei marine sponge with a yellow interior and noticed the patchy distribution of one metabolite. This compound was isolated and its structure was studied by a combination of spectrometric analyses and chemical degradation, showing it to be a congener in the theonellamide class of bicyclic peptides. Theonellamides had previously been isolated by us only from T. swinhoei with a white interior and not from those with a yellow interior.
- Fukuhara, Kazuya,Takada, Kentaro,Watanabe, Ryuichi,Suzuki, Toshiyuki,Okada, Shigeru,Matsunaga, Shigeki
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p. 2595 - 2599
(2018/12/13)
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- Chromatographic Resolution of α-Amino Acids by (R)-(3,3'-Halogen Substituted-1,1'-binaphthyl)-20-crown-6 Stationary Phase in HPLC
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Three new chiral stationary phases (CSPs) for high-performance liquid chromatography were prepared from R-(3,3'-halogen substituted-1,1'-binaphthyl)-20-crown-6 (halogen = Cl, Br and I). The experimental results showed that R-(3,3'-dibromo-1,1'-binaphthyl)-20-crown-6 (CSP-1) possesses more prominent enantioselectivity than the two other halogen-substituted crown ether derivatives. All twenty-one α-amino acids have different degrees of separation on R-(3,3'-dibromo-1,1'-binaphthyl)-20-crown-6-based CSP-1 at room temperature. The enantioselectivity of CSP-1 is also better than those of some commercial R-(1,1'-binaphthyl)-20-crown-6 derivatives. Both the separation factors (α) and the resolution (Rs) are better than those of commercial crown ether-based CSPs [CROWNPAK CR(+) from Daicel] under the same conditions for asparagine, threonine, proline, arginine, serine, histidine and valine, which cannot be separated by commercial CR(+). This study proves the commercial usefulness of the R-(3,3'-dibromo-1,1'-binaphthyl)-20-crown-6 chiral stationary phase.
- Wu, Peng,Wu, Yuping,Zhang, Junhui,Lu, Zhenyu,Zhang, Mei,Chen, Xuexian,Yuan, Liming
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supporting information
p. 1037 - 1042
(2017/07/25)
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- Degradation of complexons derived from succinic acid under UV radiation
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The destruction of complexons derived from succinic acid under the action of UV radiation was studied. IR spectroscopy, thin-layer paper chromatography, and complexometric titration were used to determine the destruction products of these complexons. It was found that the complexons decompose under UV irradiation substantially more easily than ethylenediaminetetraacetic acid does, and the products of their decomposition can undergo a biological utilization under natural conditions. The data obtained in the study make it possible to choose, instead of ethylenediaminetetraacetic acid, ligands that will be nearly fully destructible in the light without deteriorating the ecology.
- Smirnova,Khizhnyak,Nikol’skii,Khalyapina, Ya. M.,Pakhomov
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p. 507 - 511
(2017/08/02)
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- Purification, structural characterization and bioactivity evaluation of a novel proteoglycan produced by Corbicula fluminea
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A novel proteoglycan, named CFPS-11, was isolated from Corbicula fluminea, which is a food source of freshwater bivalve mollusk. CFPS-11 had an average molecular weight of 807.7 kDa and consisted of D-glucose and D-glucosamine in a molar ratio of 12.2:1.0. The protein moiety (~5%) of CFPS-11 was covalently bonded to the polysaccharide chain in O-linkage type through both serine and thereonine residues. The polysaccharide chain of CFPS-11 was composed of (1 → 4)-α-D-glucopyranosyl and (1 → 3,6)-α-D-glucopyranosyl residues, which branched at O-6. The branch chain consisted of (1 →)-α-D-glucopyranosyl and (1 →)-α-D-N-acetylglucosamine residues. CFPS-11 exhibited significant antioxidant activity in a dose-dependent manner and remarkable inhibition activities against α-amylase and α-glucosidase by in vitro assays. These findings indicated that the CFPS-11 from C. fluminea has the potential for development as a health food ingredient.
- Yan, Jing-Kun,Wang, Yao-Yao,Qiu, Wen-Yi,Wu, Li-Xia,Ding, Zhi-Chao,Cai, Wu-Dan
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- Efficient Enzymatic Preparation of13N-Labelled Amino Acids: Towards Multipurpose Synthetic Systems
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Nitrogen-13 can be efficiently produced in biomedical cyclotrons in different chemical forms, and its stable isotopes are present in the majority of biologically active molecules. Hence, it may constitute a convenient alternative to Fluorine-18 and Carbon-11 for the preparation of positron-emitter-labelled radiotracers; however, its short half-life demands for the development of simple, fast, and efficient synthetic processes. Herein, we report the one-pot, enzymatic and non-carrier-added synthesis of the13N-labelled amino acids l-[13N]alanine, [13N]glycine, and l-[13N]serine by using l-alanine dehydrogenase from Bacillus subtilis, an enzyme that catalyses the reductive amination of α-keto acids by using nicotinamide adenine dinucleotide (NADH) as the redox cofactor and ammonia as the amine source. The integration of both l-alanine dehydrogenase and formate dehydrogenase from Candida boidinii in the same reaction vessel to facilitate the in situ regeneration of NADH during the radiochemical synthesis of the amino acids allowed a 50-fold decrease in the concentration of the cofactor without compromising reaction yields. After optimization of the experimental conditions, radiochemical yields were sufficient to carry out in vivo imaging studies in small rodents.
- da Silva, Eunice S.,Gómez-Vallejo, Vanessa,Baz, Zuri?e,Llop, Jordi,López-Gallego, Fernando
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p. 13619 - 13626
(2016/09/13)
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- Variochelins, Lipopeptide Siderophores from Variovorax boronicumulans Discovered by Genome Mining
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Photoreactive siderophores have a major impact on the growth of planktonic organisms. To date, these molecules have mainly been reported from marine bacteria, although evidence is now accumulating that some terrestrial bacteria also harbor the biosynthetic potential for their production. In this paper, we describe the genomics-driven discovery and characterization of variochelins, lipopeptide siderophores from the bacterium Variovorax boronicumulans, which thrives in soil and freshwater habitats. Variochelins are different from most other lipopeptide siderophores in that their biosynthesis involves a polyketide synthase. We demonstrate that the ferric iron complex of variochelin A possesses photoreactive properties and present the MS-derived structures of two degradation products that emerge upon light exposure.
- Kurth, Colette,Schieferdecker, Sebastian,Athanasopoulou, Kalliopi,Seccareccia, Ivana,Nett, Markus
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p. 865 - 872
(2016/05/24)
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- Influence of the amino acid side chain on peptide bond hydrolysis catalyzed by a dimeric Zr(iv)-substituted Keggin type polyoxometalate
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Peptide bond hydrolysis of 18 different dipeptides, divided into four groups depending on the nature of the amino acid side chain, by the dimeric Zr(iv)-substituted Keggin type polyoxometalate (POM) (Et2NH2)8[{α-PW11O39Zr-(μ-OH)(H2O)}2]·7H2O (1) was studied by means of kinetic experiments and 1H/13C NMR spectroscopy. The observed rate constants highly depend on the bulkiness and chemical nature of the X amino acid side chain. X-Ser and X-Thr dipeptides showed increased reactivity due to intramolecular nucleophilic attack of the hydroxyl group in the side chain on the amide carbon, resulting in a reactive ester intermediate. A similar effect in which the amino acid side chain acted as an internal nucleophile was observed for the hydrolysis of Gly-Asp. Interestingly, in the presence of 1 deamidation of Gly-Asn and Gly-Gln into Gly-Asp and Gly-Glu was observed. Dipeptides containing positively charged amino acid side chains were hydrolyzed at higher rates due to electrostatic interactions between the negatively charged POM surface and positive amino acid side chains.
- Ly, Hong Giang T.,Absillis, Gregory,Parac-Vogt, Tatjana N.
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supporting information
p. 976 - 984
(2016/02/19)
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- Characterization of a novel amine transaminase from Halomonas elongata
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Chiral amines are indispensable building blocks in the production of biologically active compounds. They are fundamental for the pharmaceutical industry, both as active molecules themselves and as chiral auxiliaries in asymmetric synthesis; however, the available synthetic strategies often present disadvantages. ω-Transaminases (ω-TAs) appear as an attractive alternative by driving the stereoselective amination of prochiral ketones. HEWT is a novel amine transaminase from the moderate halophilic bacterium, Halomonas elongata DSM 2581, which is highly (S)-selective, being able to fully convert (S)-1-phenylethylamine to acetophenone and showing no activity with the corresponding (R)-1-phenylethylamine. HEWT has a broad substrate scope, active with a range of amino donors and acceptors, and naturally accepts isopropylamine (IPA) as amino donor in asymmetric synthesis providing a 41% conversion of pyruvate in 24 h at 37°C starting with 1:1 molar ratio between the reagents. HEWT also accepts ortho-xylylenediamine as amino donor in for amine synthesis, in particular, with benzaldehyde yielding high conversions between 90 and 95%. The enzyme is also tolerant to the presence of cosolvents up to 20% making it a promising candidate for industrial applications.
- Cerioli, Lorenzo,Planchestainer, Matteo,Cassidy, Jennifer,Tessaro, Davide,Paradisi, Francesca
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p. 141 - 150
(2015/09/01)
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- Fabrication of mesoporous carbon tube and foam: Application as supports in enantio-selective separation of optically pure amino acid from racemates
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The mesoporous monolithic carbon (MMC) foams and carbon tubes were newly fabricated in cmscale using the mixture of triblock copolymers and phenol/HCHO resin precursors. The regular mesoporosity were formed in the body of MMC foam and carbon fibers. In this work, the organic phases containing chiral ARCA adsorbent and a phase transfer catalyst were coated on the surfaces of mesoporous carbon support, and this ARCA/carbon mixture was adopted for the enantioselective separation of amino acid in the circulation system. (S)-ARCA coated MMC support showed high selcetivity up to 90% for the separation of D-type phenylalanine, serine and tryptophan from racemic mixtures.
- Jeon, Hoon-Gi,Lee, Ju-Hyun,Kim, Gye-Ryung,Park, Da-Min,Kim, Geon-Joong
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p. 334 - 338
(2015/03/18)
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- Efficient synthesis of chiral binaphthol aldehyde with phenyl ether linkage for enantioselective extraction of amino acids
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A binaphthol aldehyde with phenyl ether linkage, compound 2, has been synthesized starting from binaphthol-3-carboxylic acid. The axially chiral binaphthol ring was racemized during the synthesis due to high temperatures required in O-phenylation reaction. The enantiomerically pure form of 2 was obtained from the resolution of the diastereomeric imine of 2. Optically pure compound (S)-2 was applied to the enantioselective liquid-liquid extraction of amino acid between CH2Cl2 and aqueous layers.The stereoselectivities, that is, D/L ratio of the amino acid extracted, ranged from 3.57 to 11.1. One carbon was absent in compound (S)-2 compared to the compound (S)-1 with benzyl ether linkage, which differentiated the conformations of their imines formed with amino acids.
- Choi, Misun,Jun, Moo-Jin,Kim, Kwan Mook
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p. 1834 - 1837
(2015/07/15)
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- Anti-inflammatory activity of a new cyclic peptide, citrusin XI, isolated from the fruits of Citrus unshiu
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Ethnopharmacological relevance Citrus unshiu (Rutaceae) is an easy-peeling citrus fruit, which has been used as a traditional Korean medicine for improving skin elasticity, relieving fatigue and cough, and preventing bronchitis, flu, and various cancers. However, its active components associated with anti-inflammation and underlying mechanisms remain unknown. In this study, we investigated the active constituents from the fruits of Citrus unshiu and evaluated the anti-inflammatory activity in order to support the traditional usage of Citrus unshiu. Material and methods Repeated column chromatography, together with a semi-preparative HPLC purification was used to separate the bioactive constituent from the EtOAc soluble fraction of the EtOH extract of Citrus unshiu fruits. Anti-inflammatory effects of the isolated compounds on lipopolysaccharide (LPS)-induced production of pro-inflammatory mediators were examined using RAW264.7 macrophage cells. Results A new cyclic peptide, citrusin XI (1), was isolated and identified from the fruits of Citrus unshiu. The structure of compound 1 was elucidated by spectroscopic analysis, including 1D and 2D nuclear magnetic resonance (NMR) (1H, 13C, COSY, HMQC and HMBC experiments), and high resolution (HR)-mass spectrometry, and its absolute configurations were further confirmed by the Marfeys method. Compound 1 decreased NO production in LPS-stimulated RAW264.7 cells in a dose-dependent manner with an IC50 value of 70 μM. Compound 1 suppressed NO production by decreasing iNOS expression but COX-2 expression was slightly associated with the reduction by compound 1 in LPS-induced RAW264.7 cells. Furthermore, compound 1 inhibited NF-κB activation by blocking IκBα degradation and NF-κB phosphorylation in LPS-stimulated RAW264.7 cells. Conclusions These results indicate that a new cyclic peptide, citrusin XI, from Citrus unshiu fruits has anti-inflammatory properties that inhibit the release of pro-inflammatory mediators. Compound 1 decreases NO production by decreasing iNOS expression and NF-κB activation associated with IκBα degradation and NF-κB phosphorylation in LPS-induced RAW264.7 cells. This is the first study to clarify the underlying mechanism of the anti-inflammatory effect exerted by a pure isolated compound from Citrus unshiu in LPS-stimulated RAW264.7 macrophage cells. The phytochemical, citrusin XI of Citrus unshiu may serve as lead compound in the design of new agents for preventing and treating inflammatory diseases.
- Noh, Hyung Jun,Hwang, Dukhyun,Lee, Eun Suk,Hyun, Jae Wook,Yi, Pyoung Ho,Kim, Geum Soog,Lee, Seung Eun,Pang, Changhyun,Park, Yong Joo,Chung, Kyu Hyuck,Kim, Gun Do,Kim, Ki Hyun
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p. 106 - 112
(2015/03/05)
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- Degradation and antioxidant activities of peptides and zinc-peptide complexes during in vitro gastrointestinal digestion
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The degradation characteristics of three peptides (Ser-Met, Asn-Cys-Ser, and glutathione) and their zinc-peptide complexes were studied using a two-stage in vitro digestion model. Enzyme-resistant peptides and zinc-peptide complexes, antioxidant activities, and free amino acids released by digestive enzymes, were measured in this study. The results revealed that the three peptides and their zinc-peptide complexes were resistant to pepsin but not to pancreatin. Pancreatin can partly hydrolyse both peptides and zinc-peptide complexes, but more than half of them remaining in their original form after gastrointestinal digestion. The coordination of zinc improved the enzymatic resistance of the peptide due to lower solubility of complexes and affected the hydrolytic site of pepsin and pancreatin. Zinc-Asn-Cys-Ser, which is highly resistant to enzymatic hydrolysis and maintains Zn in a soluble form, may have potential to improve Zn bioavailability.
- Wang, Chan,Li, Bo,Wang, Bo,Xie, Ningning
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p. 733 - 740
(2015/01/09)
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- Characterization of two putative prolinases (PepR1 and PepR2) from Lactobacillus plantarum WCFS1: Occurrence of two isozymes with structural similarity and different catalytic properties
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Two putative prolinases (PepR1 and PepR2) of Lactobacillus plantarum WCSF1 share 48.5% amino acid sequence identity (55.5% at the DNA level); however, PepR1 exhibits over 80% identity at the protein level with other lactobacilli prolinases while PepR2 exhibits only 51% or less identity. In this study, the putative genes were overexpressed in Escherichia coli, purified to gel electrophoretic homogeneity, and then characterized. Purified PepR1 and PepR2 hydrolysed Pro-Xaa dipeptide substrates at similar rates, proving their nature as prolinases. Structural analyses using circular dichroism, dynamic light scattering, gel filtration, and molecular modelling revealed that the two prolinases have similar structural characteristics: high β-sheet content, homotetrameric structure, and similar folding to the PepI/PepL/PepR peptidase family. However, kinetic and thermodynamic analyses of PepR1 and PepR2 indicated differences in many aspects: optimum temperatures (25 and 30 °C, respectively), optimum pH (pH 7.5 and 8.0, respectively), substrate specificities (high stringency of PepR2), kinetic parameters, and thermal stability (29 and 48 °C, respectively). Also, these prolinases behaved differently towards inhibitor treatments, suggesting structural and/or functional differences in their active sites. Differences in the two prolinases would contribute to a diversity of catalytic activities, so that they work together cooperatively and complementarily to hydrolyse proline-containing peptides with broader specificity, working pH, working temperature, and higher efficiency, thus allowing adaptation to a wider range of environments.
- Huang, Yanyu,Tanaka, Takuji
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- Comparative study of the reactivity of zirconium(IV)-substituted polyoxometalates towards the hydrolysis of oligopeptides
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The hydrolytic activity of the ZrIV-substituted Keggin-type (Et2NH2)8[{α-PW11O39Zr-(μ-OH)(H2O)}2]·7H2O (1), Lindqvist-type (Me4N)2[W5O18Zr(H2O)3] (2), and Wells-Dawson-type Na14[Zr4(P2W16O59)2(μ3-O)2(OH)2(H2O)4]·57H2O (3) polyoxometalates (POMs) towards the peptide bonds in the oligopeptides triglycine, tetraglycine, glycylglycylhistidine, and glycylserylphenylalanine was investigated by kinetic methods and multinuclear NMR spectroscopy. 31P NMR and UV/Vis spectroscopy showed that 1-3 were stable under the conditions used to study peptide bond hydrolysis. The reactivity of 1-3 towards oligopeptides was compared on the basis of the amount of free glycine produced at a certain time increment. In the presence of 1-3, rate constants in the range 6.25×10-7 to 10.14×10-7 s-1 were obtained, whereas no hydrolysis was observed after one month in the absence of these POMs. The results showed that the Keggin-type complex 1 was the most active towards peptide bond hydrolysis in tri- and tetrapeptides. 1H and 13C NMR spectroscopy showed that triglycine, tetraglycine, and glycylserylphenylalanine interact with 1 and 2 preferentially through the amine nitrogen atom and the N-terminal amide oxygen atom to activate the peptide bond towards hydrolysis. The coordination of glycylglycylhistidine resulted in multiple complexes with 1-3 as a result of additional imidazole coordination to the ZrIV centers.
- Ly, Hong Giang T.,Absillis, Gregory,Parac-Vogt, Tatjana N.
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p. 2206 - 2215
(2015/05/13)
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- Microseiramide from the freshwater cyanobacterium Microseira sp. UIC 10445
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Abstract Microseiramide (1), a cyclic heptapeptide, was isolated from a sample of the freshwater cyanobacterium Microseira sp. UIC 10445 collected in a shallow lake in Northern Indiana. Taxonomic identification of UIC 10445 was performed by a combination of morphological and phylogenetic characterization. Phylogenetic analysis revealed that UIC 10445 was a member of the recently described genus Microseira, which is phylogenetically distinct from the morphologically similar genera, Moorea and Lyngbya. The planar structure of microseiramide (1) was determined by extensive 1D and 2D NMR experiments as well as HRESIMS analysis. The absolute configurations of amino acid residues were determined using acid hydrolysis followed by the advanced Marfey's analysis. Microseiramide (1) is the first cyclic peptide reported from a Microseira sp., and the structure of microseiramide (1) is distinct from the previously known metabolites from cyanobacteria of the genera Moorea and Lyngbya.
- Luo, Shangwen,Krunic, Aleksej,Chlipala, George E.,Orjala, Jimmy
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- Isolation, Characterization, and Synthesis of the Barrettides: Disulfide-Containing Peptides from the Marine Sponge Geodia barretti
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Two disulfide-containing peptides, barrettides A (1) and B (2), from the cold-water marine sponge Geodia barretti are described. Those 31 amino acid residue long peptides were sequenced using mass spectrometry methods and structurally characterized using NMR spectroscopy. The structure of 1 was confirmed by total synthesis using the solid-phase peptide synthesis approach that was developed. The two peptides were found to differ only at a single position in their sequence. The three-dimensional structure of 1 revealed that these peptides possess a unique fold consisting of a long β-hairpin structure that is cross-braced by two disulfide bonds in a ladder-like arrangement. The peptides are amphipathic in nature with the hydrophobic and charged residues clustered on separate faces of the molecule. The barrettides were found not to inhibit the growth of either Escherichia coli or Staphylococcus aureus but displayed antifouling activity against barnacle larvae (Balanus improvisus) without lethal effects in the concentrations tested. (Figure Presented).
- Carstens, Bodil B.,Rosengren, K. Johan,Gunasekera, Sunithi,Schempp, Stefanie,Bohlin, Lars,Dahlstr?m, Mia,Clark, Richard J.,G?ransson, Ulf
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p. 1886 - 1893
(2015/09/08)
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- Enantiospecific C-H Activation Using Ruthenium Nanocatalysts
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The activation of C-H bonds has revolutionized modern synthetic chemistry. However, no general strategy for enantiospecific C-H activation has been developed to date. We herein report an enantiospecific C-H activation reaction followed by deuterium incorporation at stereogenic centers. Mechanistic studies suggest that the selectivity for the α-position of the directing heteroatom results from a four-membered dimetallacycle as the key intermediate. This work paves the way to novel molecular chemistry on nanoparticles.
- Taglang, Céline,Martínez-Prieto, Luis Miguel,Del Rosal, Iker,Maron, Laurent,Poteau, Romuald,Philippot, Karine,Chaudret, Bruno,Perato, Serge,Sam Lone, Ana?s,Puente, Céline,Dugave, Christophe,Rousseau, Bernard,Pieters, Grégory
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supporting information
p. 10474 - 10477
(2015/09/02)
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- Site-specific labeling of synthetic peptide using the chemoselective reaction between N-methoxyamino acid and isothiocyanate
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Site-specific labeling of synthetic peptides carrying N-methoxyglycine (MeOGly) by isothiocyanate is demonstrated. A nonapeptide having MeOGly at its N-terminus was synthesized by the solid-phase method and reacted with phenylisothiocyanate under various conditions. In acidic solution, the reaction specifically gave a peptide having phenylthiourea structure at its N-terminus, leaving side chain amino group intact. The synthetic human β-defensin-2 carrying MeOGly at its N-terminus or the side chain amino group of Lys10 reacted with phenylisothiocyanate or fluorescein isothiocyanate also at the N-methoxyamino group under the same conditions, demonstrating that this method is generally useful for the site-specific labeling of linear synthetic peptides as well as disulfide-containing peptides.
- Hara, Toshiaki,Purwati, Euis Maras,Tainosyo, Akira,Kawakami, Toru,Hojo, Hironobu,Aimoto, Saburo
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p. 765 - 769
(2015/09/21)
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- Cyclopentapeptides from Dianthus chinensis
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A new cyclopentapeptide dianthin I (1), together with two known ones pseudostellarin A (2) and heterophyllin J (3), was isolated from the aerial parts of Dianthus chinensis. The structure of 1 was elucidated as cyclo-(Gly1- l-Phe2- l-Pro3- l-Ser4- l-Phe5) on the basis of extensive spectroscopic analyses and chemical methods.
- Han, Jing,Huang, Maobo,Wang, Zhe,Zheng, Yuqing,Zeng, Guangzhi,He, Wenjun,Tan, Ninghua
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p. 550 - 553
(2015/07/02)
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- SEPARATING AGENT AND MANUFACTURING METHOD THEREOF
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An embodiment of the present invention is a separating agent wherein a group represented by a chemical formula of: or a group represented by a chemical formula of: is introduced on a surface thereof.
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Paragraph 0067; 0068; 0069; 0070; 0071; 0072; 0091; 0092
(2015/01/07)
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- Modification of cellulose acetates for preparing chiral sorbents
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Modification of cellulose acetates via sorption-desorption of vapors of mesogenic solvents in which the polymer forms a lyotropic liquid crystal phase and of mixtures of these solvents with water leads to the formation of a new chiral structure of the polymeric sample. This is manifested in a significant change in the value and even sign of the specific optical rotation of the polysaccharide system. The sorbents based on cellulose acetates that have been modified by such treatment exhibit specific affinity for definite optical antipodes. When a racemic mixture of L- and D-isomers of amino acids is passed through this sorbent, it acts as a chiral filter owing to "steric recognition" of one of the enantiomers, so that the filtrate contains an optically pure product (isomer). The revealed effects served as a basis for the development of a new procedure for preparation of optically pure stereoisomers of chiral products.
- Shipovskaya,Gegel',Shchegolev
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p. 1326 - 1333
(2015/05/20)
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- Fabrication of meso/macroporous carbon monolith and its application as a support for adsorptive separation of D-amino acid from racemates
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(S)-Alanine Racemase Chiral Analogue ((S)-ARCA) was used as an efficient adsorbent for the selective separation of D-amino acids (D-AAs), which are industrially important as chiral building blocks for the synthesis of pharmaceutical intermediates. The organic phase, containing (S)-ARCA adsorbent and phase transfer reagents, such as ionic liquid type molecules (Tetraphenylphosphonium chloride (TPPC), Octyltriphenylphosponium bromide (OTPPBr)), were coated on the surfaces of mesoporous carbon supports. For the immobilization of chiral adsorbents, meso/macroporous monolithic carbon (MMC), having bimodal pore structures with high surface areas and pore volumes, were fabricated. The separation of chiral AAs by adsorption onto the heterogeneous (S)-ARCA was performed using a continuous flow type packed bed reactor system. The effects of loading amount of ARCA on the support, the molar ratio of AA to ARCA, flow rates, and the type of phase transfer reagent (PTR) on the isolation yields and the optical purity of product D-AAs were investigated. D-AAs were selectively combined to (S)-ARCA through imine formation reaction in an aqueous basic solution of racemic D/L-AA. The (S)-ARCA coated MMC support showed a high selectivity, up to 95 ee%, for the separation of D-type phenylalanine, serine and tryptophan from racemic mixtures. The ionic liquids TPPC and OTPPBr exhibited superior properties to those of the ionic surfactant Cetyltrimethyl ammonium bromide (CTAB), as a PTR, showing constant optical purities of 95 ee%, with high isolation yields for five repeated reuses. The unique separation properties in this heterogeneous adsorption system should provide for an expansion of the applications of porous materials for commercial processes.
- Park, Da-Min,Jeon, Sang Kwon,Yang, Jin Yong,Choi, Sung Dae,Kim, Geon Joong
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p. 1720 - 1726
(2014/07/07)
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- A novel serine hydroxymethyltransferase from marine bacterium Alcanivorax sp. and its application on enzymatic synthesis of L-serine
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A novel glyA gene from the marine bacterium Alcanivorax sp. was cloned and expressed in Escherichia coli BL21 (DE3). The recombinant glyA encodes a polypeptide of 418 amino acids, which was designated as AdSHMT that shows the highest identity (70%) with a SHMT from Shewanella algae. The purified enzyme showed a single band at about 45 kDa by SDS-PAGE analysis. It was found that AdSHMT exhibited the maximal activity at 50 °C and pH 7.0. The K m, Vmax, and Kcat values of AdSHMT against dl-threo-3-phenylserine were calculated to be 0.097 mol/L, 3.255 μmol/min/mg and 2.451/s, respectively. More importantly, RP-HPLC detection showed that the AdSHMT achieved an 88.37% molecular conversion rate in catalyzing glycine to l-serine, with the final concentration of l-serine being 353.15 mM in the reaction at 35°C and 22nd hour when the initial concentration of the substrate (glycine) was 0.399 M. The molecular conversion rate of the AdSHMT from the Alcanivorax sp. was 1.26-fold that of the EcSHMT from the E. coli, which is currently applied in industrial production. Therefore, AdSHMT has the potential for industrial applications due to its high enzymatic conversion rate.
- Yuan, Shaohui,Jiang, Wei,Chen, Lin,Guo, Yiming,Liu, Ziduo
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- Deracemization of amino acids by coupling transaminases of opposite stereoselectivity
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Biocatalytic deracemization of amino acids without relying on oxidase-based deamination of an unwanted enantiomer was demonstrated by coupling a-and w-transaminases displaying opposite stereoselectivity. This strategy employs isopropylamine and a keto acid as cosubstrates and is free of generation of hydrogen peroxide which is troublesome in the conventional oxidase-based methods.
- Park, Eul-Soo,Shin, Jong-Shik
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p. 3505 - 3509
(2015/02/19)
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- Cyclic lipodepsipeptides verlamelin A and B, isolated from entomopathogenic fungus Lecanicillium sp.
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Verlamelin and its new derivative (verlamelin B) were isolated from fermentation broth of entomopathogenic fungus Lecanicillium sp. HF627. As the structural elucidation of verlamelin so far was only preliminary, we studied and determined the absolute structure of these two compounds to be cyclo(5S-hydroxytetradecanoic acid-D-alloThr/Ser-D-Ala-L-Pro-L-Gln-D-Tyr-L-Val). This is the first study that precisely analyzed the structure of verlamelin.
- Ishidoh, Kei-Ichi,Kinoshita, Hiroshi,Igarashi, Yasuhiro,Ihara, Fumio,Nihira, Takuya
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p. 459 - 463
(2014/07/08)
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- Structures and solution conformational dynamics of stylissamides G and H from the Bahamian Sponge Stylissa caribica
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Two new peptides, stylissamides G and H, were isolated from extracts of a sample of Stylissa caribica collected in deep waters of the Caribbean Sea. A single sample of S. caribica among a collection of 10 samples that were examined by LC-MS appeared to be a different chemotype from the others in that it lacked the familiar pyrrole-2-aminoimidazole alkaloids, stevensine and oroidin, and contained peptides of the stylissamide class. The structures of the title compounds were solved by integrated analysis of the MS and NMR spectra and chemical degradation. The solution conformation of stylissamide G was briefly examined by electronic circular dichroism and temperature-dependent 1H NMR chemical shifts of amide NH signals, which supported a conformationally rigid macrocycle.
- Wang, Xiao,Morinaka, Brandon I.,Molinski, Tadeusz F.
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supporting information
p. 625 - 630
(2014/04/17)
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