- Nanohybrids composed of quantum dots and cytochrome P450 as photocatalysts
-
(Chemical Equation Presented) Synthesis with light: CdS quantum dots (QDs) generate superoxide and hydroxyl radicals upon UV irradiation in aqueous solution. The radicals are used for activating P450BSβ enzymes attached at the QD surface, effecting the catalytic transformation of myristic acid into α- and β-hydroxymyristic acid (see picture, R = (CH 2)10CH3).
- Ipe, Binil Itty,Niemeyer, Christof M.
-
-
Read Online
- Structure of the unusual Sinorhizobium fredii HH103 lipopolysaccharide and its role in symbiosis
-
Rhizobia are soil bacteria that form important symbiotic associations with legumes, and rhizobial surface polysaccharides, such as K-antigen polysaccharide (KPS) and lipopolysaccharide (LPS), might be important for symbiosis. Previously, we obtained a mutant of Sinorhizobium fredii HH103, rkpA, that does not produce KPS, a homopolysaccharide of a pseudaminic acid derivative, but whose LPS electrophoretic profile was indistinguishable from that of the WT strain. We also previously demonstrated that the HH103 rkpLMNOPQ operon is responsible for 5-acetamido-3,5,7,9-tetradeoxy-7-(3-hydroxybutyramido)-L-glyc-ero-L-manno-nonulosonic acid [Pse5NAc7(3OHBu)] production and is involved in HH103 KPS and LPS biosynthesis and that an HH103 rkpM mutant cannot produce KPS and displays an altered LPS structure. Here, we analyzed the LPS structure of HH103 rkpA, focusing on the carbohydrate portion, and found that it contains a highly heterogeneous lipid A and a peculiar core oligosaccharide composed of an unusually high number of hexuronic acids containing b-configured Pse5NAc7(3OHBu). This pseudaminic acid derivative, in its a-configuration, was the only structural component of the S. fredii HH103 KPS and, to the best of our knowledge, has never been reported from any other rhizobial LPS. We also show that Pse5NAc7(3OHBu) is the complete or partial epitope for a mAb, NB6-228.22, that can recognize the HH103 LPS, but not those of most of the S. fredii strains tested here. We also show that the LPS from HH103 rkpM is identical to that of HH103 rkpA but devoid of any Pse5NAc7(3OHBu) residues. Notably, this rkpM mutant was severely impaired in symbiosis with its host, Macroptilium atropurpureum.
- Di Lorenzo, Flaviana,Speciale, Immacolata,Silipo, Alba,Alías-Villegas, Cynthia,Acosta-Jurado, Sebastián,Rodríguez-Carvajal, Miguel-ángel,Dardanelli, Marta S.,Palmigiano, Angelo,Garozzo, Domenico,Ruiz-Sainz, José-Enrique,Molinaro, Antonio,Vinardell, José-María
-
p. 10969 - 10987
(2021/01/07)
-
- α-Oxidative decarboxylation of fatty acids catalysed by cytochrome P450 peroxygenases yielding shorter-alkyl-chain fatty acids
-
Cytochrome P450 peroxygenases belonging to the CYP152 family catalyse the oxidation of fatty acids using H2O2. CYP152N1 isolated from Exiguobacterium sp. AT1b exclusively catalyses the α-selective hydroxylation of myristic acid at physiological H2O2 concentration. However, a series of shorter-alkyl-chain fatty acids such as tridecanoic acid were produced from myristic acid by increasing the concentration of H2O2 (1-10 mM). The yield of tridecanoic acid from myristic acid reached 17%. An 18O-labeled oxidant study suggested that CYP152N1 catalysed the overoxidation of α-hydroxymyristic acid to form α-ketomyristic acid, which in turn was spontaneously decomposed by H2O2 to yield tridecanoic acid. Crystal structure analysis of CYP152N1 revealed its high similarity to other CYP152 family enzymes, such as CYP152A1 and CYP152B1. MD simulations of α-hydroxymyristic acid accommodated in CYP152N1 proposed a possible pre-oxidation conformation of α-hydroxymyristic acid for the decarboxylation reaction.
- Onoda, Hiroki,Shoji, Osami,Suzuki, Kazuto,Sugimoto, Hiroshi,Shiro, Yoshitsugu,Watanabe, Yoshihito
-
p. 434 - 442
(2018/02/07)
-
- Photobiocatalytic decarboxylation for olefin synthesis
-
Here, we describe the combination of OleTJE with a light-driven in situ H2O2-generation system for the selective and quantitative conversion of fatty acids into terminal alkenes. The photobiocatalytic system shows clear advantages regarding enzyme activity and yield, resulting in a simple and efficient system for fatty acid decarboxylation.
- Zachos, Ioannis,Ga?meyer, Sarah Katharina,Bauer, Daniel,Sieber, Volker,Hollmann, Frank,Kourist, Robert
-
supporting information
p. 1918 - 1921
(2015/02/05)
-
- In situ formation of H2O2 for P450 peroxygenases
-
An in situ H2O2 generation approach to promote P450 peroxygenases catalysis was developed through the use of the nicotinamide cofactor analogue 1-benzyl-1,4-dihydronicotinamide (BNAH) and flavin mononucleotide (FMN). Final productivity could be enhanced due to higher enzyme stability at low H2O2 concentrations. The H2O2 generation represented the rate-limiting step, however it could be easily controlled by varying both FMN and BNAH concentrations. Further characterization can result in an optimized ratio of FMN/BNAH/O2/biocatalyst enabling high reaction rates while minimizing H2O2-related inactivation of the enzyme.
- Paul, Caroline E.,Churakova, Ekaterina,Maurits, Elmer,Girhard, Marco,Urlacher, Vlada B.,Hollmann, Frank
-
p. 5692 - 5696
(2015/01/09)
-
- Identification of four new agr quorum sensing-interfering cyclodepsipeptides from a marine Photobacterium
-
During our search for new natural products from the marine environment, we discovered a wide range of cyclic peptides from a marine Photobacterium, closely related to P. halotolerans. The chemical fingerprint of the bacterium showed primarily non-ribosomal peptide synthetase (NRPS)-like compounds, including the known pyrrothine antibiotic holomycin and a wide range of peptides, from diketopiperazines to cyclodepsipeptides of 500-900 Da. Purification of components from the pellet fraction led to the isolation and structure elucidation of four new cyclodepsipeptides, ngercheumicin F, G, H, and I. The ngercheumicins interfered with expression of virulence genes known to be controlled by the agr quorum sensing system of Staphylococcus aureus, although to a lesser extent than the previously described solonamides from the same strain of Photobacterium.
- Kjaerulff, Louise,Nielsen, Anita,Mansson, Maria,Gram, Lone,Larsen, Thomas O.,Ingmer, Hanne,Gotfredsen, Charlotte H.
-
p. 5051 - 5062
(2014/02/14)
-
- Crystal structure of H2O2-dependent cytochrome P450SPαwith its bound fatty acid substrate: Insight into the regioselective hydroxylation of fatty acids at the α position
-
Cytochrome P450SPα (CYP152B1) isolated from Sphingomonas paucimobilis is the first P450 to be classified as a 2O 2-dependent P450. P450SPα hydroxylates fatty acids with high α-regioselectivity. Herein we report the crystal structure of P450SPαwith palmitic acid as a substrate at a resolution of 1.65 A. The structure revealed that the Cα of the bound palmitic acid in one of the alternative conformations is 4.5 A from the heme iron. This conformation explains the highly selective α-hydroxylation of fatty acid observed in P450SPα. Mutations at the active site and the F-G loop of P450SPα did not impair its regioselectivity. The crystal structures of mutants (L78F and F288G) revealed that the location of the bound palmitic acid was essentially the same as that in the WT, although amino acids at the active site were replaced with the corresponding amino acids of cytochrome P450BSβ (CYP152A1), which shows β-regioselectivity. This implies that the high regioselectivity of P450SPα is caused by the orientation of the hydrophobic channel, which is more perpendicular to the heme plane than that of P450 BSβ.
- Fujishiro, Takashi,Shoji, Osami,Nagano, Shingo,Sugimoto, Hiroshi,Shiro, Yoshitsugu,Watanabe, Yoshihito
-
experimental part
p. 29941 - 29950
(2012/04/10)
-
- Amino acid derivatives and their use as phospholipase A2 inhibitor
-
PCT No. PCT/JP95/00068 Sec. 371 Date Nov. 12, 1996 Sec. 102(e) Date Nov. 12, 1996 PCT Filed Jan. 23, 1995 PCT Pub. No. WO95/19959 PCT Pub. Date Jul. 27, 1995The present invention relates to a novel fatty acid derivative of the following formula: wherein R
- -
-
-
- Syntheses and biological evaluation of novel pseudomycin side-chain analogues. Part 2
-
A series of aliphatic side-chain analogues of pseudomycin was synthesized and evaluated during the course of our side-chain SAR effort. We found that several of the pseudomycin side-chain analogues (e.g., 10) exhibited good in vitro activity against all t
- Chen, Shu-Hui,Sun, Xicheng,Boyer, Robert,Paschal, Jonathan,Zeckner, Doug,Current, William,Zweifel, Mark,Rodriguez, Michael
-
p. 2107 - 2110
(2007/10/03)
-
- Towards the Chemoenzymatic Synthesis of Lipid A
-
New procedures have been developed for the synthesis of the two important components of lipid A; one is the lipase-catalyzed resolution of 3-hydroxytetradecanoic acid in tetrahydrofuran using vinyl acetate and the other is the synthesis of the disaccharide moiety using glycosylphosphite as the glycosylating reagent.
- Sugai, Takeshi,Ritzen, Helena,Wong, Chi-Huey
-
p. 1051 - 1058
(2007/10/02)
-
- Isolation and Structural Elucidation of Syringostatins, Phytotoxins Produced by Pseudomonas syringae pv.syringae Lilac Isolate
-
A bacterial strain of Pseudomonas syringae pv. syringae isolated from lilac was found to produce a homologous mixture of phytotoxins different from syringomycin and syringotoxin.The toxins were termed syringostatins and the structures of the main components, syringostatins A and B, were determined by 2D-NMR spectroscopy and mass spectrometry.Minor component structures were elucidated from mass/mass spectra.
- Fukuchi, Naoyuki,Isogai, Akira,Nakayama, Jiro,Takayama, Seiji,Yamashita, Shuichi,et al.
-
p. 875 - 880
(2007/10/02)
-
- New potential immunoenhancing compounds. Synthesis and pharmacological evaluation of new long-chain 2-amido-2-deoxy-D-glucose derivatives
-
A series of long-chain fatty acids and the corresponding 2-hydroxy, 2-oxo, 3-hydroxy acid glucosamides were evaluated as immunomodulating compounds. In a preliminary screening, 2-[(2-ethoxycarbonyloxy)tetradecanoyl-amino]-2-deoxy-D-glucose (2b) and 2-(3-hydroxydodecanoyl-amino)-2-deoxy-D-glucose (5a) resulted to be the most effective in enhancing the glucosamine activity. The findings of in vitro-ex vivo tests (unidirectional mixed lymphocyte culture reaction and primary antibody production) and in vivo tests (delayed type hypersensitivity, protection against bacterial or fungal infection and against Sarcoma 180 or Lewis lung carcinoma transplants) were very encouraging and allowed to assume for the two substances a protective activity, presumably through the ability of activating phagocytic and NK cells.
- Valcavi,Albertoni,Brandt,Corsi,Farina,Foresta,Pascucci,Ramacci
-
p. 1190 - 1195
(2007/10/02)
-
- TOWARDS CHIRAL REFORMATSKY REAGENTS
-
Chiral β-hydroxyacids are obtained via the Reformatsky reaction of lactic acid derivatives with carbonyl compounds in 11-100percent optical purities.
- Basavaiah, D.,Bharathi, T. K.
-
p. 2035 - 2040
(2007/10/02)
-