- Synthesis aided structural determination of amyloid-β(1-15) glycopeptides, new biomarkers for Alzheimer's disease
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Unique tyrosine glycosylated amyloid-β(1-15) glycopeptides were synthesized with well-defined stereochemistry at the glycosidic linkages. Aided by these glycopeptides and tandem mass spectrometry analysis, the naturally existing amyloid-β glycopeptides, isolated from Alzheimer's disease patients, were determined to contain an α-linked N-acetyl galactosamine at the modified tyrosine 10 residue. Glycosylation can significantly impact the properties of amyloid-β as the glycopeptide has much lower affinity for Cu+ ions.
- Wang, Peng,Nilsson, Jonas,Brinkmalm, Gunnar,Larson, G?ran,Huang, Xuefei
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- In vitro synthesis of mucin-type O-glycans using saccharide primers comprising GalNAc-Ser and GalNAc-Thr residues
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Mucin-type O-glycosylation of serine or threonine residue in proteins is known to be one of the major post-translational modifications. In this study, two novel alkyl glycosides, Nα-lauryl-O-(2-acetamido-2-deoxy-α-D-galactopyranosyl)-L-serineamide (GalNAc-Ser-C12) and Nα-lauryl-O-(2-acetamido-2-deoxy-α-D-galactopyranosyl)-L-threonineamide (GalNAc-Thr-C12) were synthesized as saccharide primers to prime mucin-type O-glycan biosynthesis in cells. Upon incubating human gastric cancer MKN45 cells with the saccharide primers, 22 glycosylated products were obtained, and their structures were analyzed using liquid chromatography-mass spectrometry and enzyme digestion. The amounts of glycosylated products were dependent on the amino acid residues in the saccharide primers. For example, in vitro synthesis of T antigen (Galβ1-3GalNAc), fucosyl-T (Fucα1-2Galβ1-3GalNAc), and sialyl-T (NeuAcα2-3Galβ1-3GalNAc) preferred a serine residue, whereas sialyl-Tn (NeuAcα2-6GalNAc) preferred a threonine residue. Furthermore, the glycosylated products derived from GalNAc-Ser/Thr-C12 and Gal-GalNAc-Ser/Thr-C12 using cell-free synthesis showed the same amino acid selectivity as those in the cell experiments. These results indicate that glycosyltransferases involved in the biosynthesis of mucin-type O-glycans distinguish amino acid residues conjugated to GalNAc. The saccharide primers developed in this study might be useful for comparing mucin-type oligosaccharides in cells and constructing oligosaccharide libraries to study cell function.
- Sakura, Ryuma,Nagai, Kaori,Yagi, Yuka,Takahashi, Yoshihisa,Ide, Yoshimi,Yagi, Yuki,Yamamoto, Daiki,Mizuno, Mamoru,Sato, Toshinori
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- Enhanced Binding and Reduced Immunogenicity of Glycoconjugates Prepared via Solid-State Photoactivation of Aliphatic Diazirine Carbohydrates
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Biological conjugation is an important tool employed for many basic research and clinical applications. While useful, common methods of biological conjugation suffer from a variety of limitations, such as (a) requiring the presence of specific surface-exposed residues, such as lysines or cysteines, (b) reducing protein activity, and/or (c) reducing protein stability and solubility. Use of photoreactive moieties including diazirines, azides, and benzophenones provide an alternative, mild approach to conjugation. Upon irradiation with UV and visible light, these functionalities generate highly reactive carbenes, nitrenes, and radical intermediates. Many of these will couple to proteins in a non-amino-acid-specific manner. The main hurdle for photoactivated biological conjugation is very low yield. In this study, we developed a solid-state method to increase conjugation efficiency of diazirine-containing carbohydrates to proteins. Using this methodology, we produced multivalent carbohydrate-protein conjugates with unaltered protein charge and secondary structure. Compared to carbohydrate conjugates prepared with amide linkages to lysine residues using standard NHS conjugation, the photoreactive prepared conjugates displayed up to 100-fold improved binding to lectins and diminished immunogenicity in mice. These results indicate that photoreactive bioconjugation could be especially useful for in vivo applications, such as lectin targeting, where high binding affinity and low immunogenicity are desired.
- Congdon, Molly D.,Gildersleeve, Jeffrey C.
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p. 133 - 142
(2021/01/09)
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- Stereoselective Synthesis of 1,1′-Disaccharides by Organoboron Catalysis
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The highly stereoselective synthesis of 1,1′-disaccharides was achieved by using 1,2-dihydroxyglycosyl acceptors and glycosyl donors in the presence of a tricyclic borinic acid catalyst. In this reaction, the complexation of the diols and the catalyst is
- Izumi, Sanae,Kobayashi, Yusuke,Takemoto, Yoshiji
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p. 14054 - 14059
(2020/06/10)
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- Synthesis of trisaccharide repeating unit of fucosylated chondroitin sulfate
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We described the chemical synthesis of a sulfated trisaccharide repeating unit of fucosylated chondroitin sulfate (FCS), which has significant anticoagulant activity. Well-functionalized monosaccharides were readily prepared, and highly efficient glycosyl
- He, Haiqing,Chen, Dong,Li, Xiaomei,Li, Chengji,Zhao, Jin-Hua,Qin, Hong-Bo
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supporting information
p. 2877 - 2882
(2019/03/21)
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- Synthesis method and application of sialylated TF antigen and its fluorination derivatives
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The invention discloses a synthesis method and an application of a sialylated TF antigen and its fluorination derivatives. The method includes the following steps: (1) chemically synthesizing fluorogalactose and fluorogalactosamine analogues; (2) chemically synthesizing a fluorinated TF antigen; and (3) synthesizing the sialylated TF antigen and its fluorination derivatives through an enzyme technology. The flexibility of a chemical synthesis technology is combined with the high regioselectivity and the high efficiency of the enzyme synthesis technology, so the enzymatic synthesis of the fluorosialylated TF antigen is achieved for the first time, and the disadvantages of many synthesis steps, poor stereoselectivity, low yield and use of a heavy metal salt in existing chemical synthesis ofthe fluorosialylated TF antigen are overcome. A fluorotumor-associated carbohydrate antigen has a higher stability than natural carbohydrate antigen, so the sialylated TF antigen and its fluorinationderivatives have a broad application prospect in the development of novel antitumor vaccines.
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Paragraph 0054; 0069; 0071-0073
(2018/07/07)
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- A stereoselective and flexible synthesis to access both enantiomers of N-acetylgalactosamine and peracetylated N-acetylidosamine
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Synthetic approaches towards N-acetylgalactosamine (GalNAc) have been attracting considerable interest since this compound is known for its pivotal role in cell-cell interaction and receptor induced cell signaling. Herein, we present a synthetic route in which two of the four stereogenic centers present in the target compound are derived from enantiopure tartaric acid being selectively converted to epoxy alcohols. The key step is the Pd-catalyzed, stereo- and regioselective epoxide opening and subsequent nucleophilic substitution of an azide functionality. This approach enables the synthesis of the naturally D- and unnaturally L-configured GalNAc, as well as both enantiomers of the largely unknown N-acetylidosamine (IdoNAc).
- Riedl, Bettina,Schmid, Walther
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supporting information
p. 856 - 860
(2018/04/30)
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- Tn antigen and synthesis process thereof
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The invention provides a synthesis process of a Tn antigen and relates to the field of biological medicine. The synthesis process includes the steps that firstly, a donor and a receptor are subjected to a glycosylation reaction under the catalytic action of trimethylsilyl trifluoromethanesulfonate to generate glucoside, the first location of the donor is replaced and protected by phenyl trifluoroacetyl imidogen, the second location is replaced and protected by an azide group, the sixth location is replaced and protected by p-nitrobenzoyl, and the receptor is 1-benzyl-2-fluorene acyl-serine/threonine; then, all groups of the glucoside are converted, and the Tn antigen is generated. The synthesis process is simple in process, complete alpha selection can be achieved, and the yield of the Tn antigen is raised. The invention further provides the Tn antigen, and the Tn antigen is high in purity and can be used for preparing a cancer vaccine.
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Paragraph 0078; 0080; 0096; 0098; 0109; 0111
(2017/05/25)
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- Synthesis of di- and tri-saccharide fragments of Salmonella typhi Vi capsular polysaccharide and their zwitterionic analogues
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Zwitterionic polysaccharides (ZPS) behave like traditional T cell-dependent antigens, suggesting the design of new classes of vaccines alternative to currently used glycoconjugates and based on the artificial introduction of a zwitterionic charge motif onto the carbohydrate structure of pathogen antigens. Here we report the new synthesis and antigenic evaluation of di-/tri-saccharide fragments of Salmonella typhi Vi polysaccharide, as well as of their corresponding zwitterionic analogues. Our strategy is based on versatile intermediates enabling chain elongation either by iterative single monomer attachment or by faster and more flexible approach using disaccharide donors. The effect of structural modifications of the synthetic compounds on antigenic properties was evaluated by competitive ELISA. All the oligosaccharides were recognized by specific anti-Vi polyclonal antibodies in a concentration-dependent manner, and the introduction of a zwitterionic motif into the synthetic molecules did not prevent the binding.
- Fusari, Matteo,Fallarini, Silvia,Lombardi, Grazia,Lay, Luigi
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supporting information
p. 7439 - 7447
(2015/11/27)
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- Synthesis of the tumor associative α-aminooxy disaccharide of the TF antigen and its conjugation to a polysaccharide immune stimulant
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The α-aminooxy derivative of the Thomsen-Friedenriech tumor associated carbohydrate antigen has been synthesized in 11 steps utilizing a d-GalN3 acceptor carrying a pre-installed α-N- hydroxysuccinimidyl moiety. The natural α linkage was prepar
- Bourgault, Jean Paul,Trabbic, Kevin R.,Shi, Mengchao,Andreana, Peter R.
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p. 1699 - 1702
(2014/03/21)
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- Synthesis of peptides and glycopeptides with polyproline II helical topology as potential antifreeze molecules
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A library of peptides and glycopeptides containing (4R)-hydroxy-l-proline (Hyp) residues were designed with a view to providing stable polyproline II (PPII) helical molecules with antifreeze activity. A library of dodecapeptides containing contiguous Hyp
- Corcilius, Leo,Santhakumar, Gajan,Stone, Robin S.,Capicciotti, Chantelle J.,Joseph, Soumya,Matthews, Jacqueline M.,Ben, Robert N.,Payne, Richard J.
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supporting information
p. 3569 - 3581
(2013/07/05)
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- A traceless staudinger reagent to deliver diazirines
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A triarylphosphine reagent that reacts with organic azides to install amide-linked diazirines is reported. This traceless Staudinger reagent reacts with complex organic azides to yield amide-linked diazirines, thus expanding the scope of the utility of bo
- Ahad, Ali M.,Jensen, Stephanie M.,Jewett, John C.
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supporting information
p. 5060 - 5063
(2013/10/22)
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- Fluorescence-activated cell sorting and directed evolution of α-N-acetylgalactosaminidases using a quenched activity-based probe (qABP)
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An α-N-acetylgalactosamine-containing quenched activity-based probe (qABP) was designed and successfully synthesized, and it was subsequently used in directed enzyme evolution experiments aided by fluorescence-activated cell sorting (FACS) for the discove
- Kalidasan, Kamaladasan,Su, Ying,Wu, Xiaoyuan,Yao, Shao Q.,Uttamchandani, Mahesh
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supporting information
p. 7237 - 7239
(2013/08/23)
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- Synthesis of MUC1 Neoglycopeptides using efficient microwave-enhanced chaotrope-assisted click chemistry
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The first synthesis of click neoglycopeptide analogues of the biologically relevant MUC1 sequence is reported. In the process, microwave-enhanced chaotrope-assisted click reaction conditions that may be used on a routine basis for the synthesis of click p
- Lee, Dong Jun,Harris, Paul W. R.,Brimble, Margaret A.
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experimental part
p. 1621 - 1626
(2011/04/22)
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- Synthesis of an isotopically-labelled antarctic fish antifreeze glycoprotein probe
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Antifreeze glycoproteins (AFGPs) are glycosylated polypeptides produced by Antarctic and Arctic fishes, which allow them to survive in seawater at sub-zero temperatures. An investigation into the postulated enteric uptake of AFGP synthesized in the exocrine pancreas of Antarctic fishes required a custom-prepared AFGP probe that incorporated seven isotopically-labelled Ala residues for detection by mass spectrometry. The AFGPs are composed of a repetitive three amino acid unit (Ala-Ala-Thr), in which the threonine residue is glycosylated with the disaccharide β-d-Gal-(1→3) α-d-GalNAc. The synthesis of isotopically-labelled AFGP8 (1), as well as the optimized synthesis of the protected glycosylated amino acid building block 2, is reported.
- Wojnar, Joanna M.,Evans, Clive W.,Devries, Arthur L.,Brimble, Margaret A.
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experimental part
p. 723 - 731
(2012/07/14)
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- A straightforward α-selective aromatic glycosylation and its application for stereospecific synthesis of 4-methylumbelliferyl α-T-antigen
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A practical and efficient α-selective aromatic glycosylation with simple per-O-acetyl glycopyranosyl trichloroacetimidates is reported. The method is particularly effective for L-fucosyl and 2-azido-2-deoxy-d-galatosaminyl imidates, with which exclusive α-selectivity was achieved. The synthetic utility of this method was demonstrated in the stereoselective synthesis of 4-methylumbelliferyl α-T-antigen.
- Chang, Shih-Sheng,Lin, Chun-Cheng,Li, Yaw-Kuen,Mong, Kwok-Kong Tony
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scheme or table
p. 432 - 438
(2009/05/27)
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- Immunological response from an entirely carbohydrate antigen: Design of synthetic vaccines based on Tn-PS A1 conjugates
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(Figure Presented) An entirely carbohydrate-based immunogen consisting of a zwitterionic polysaccharide (ZPS) PS A1 and the well-known tumor antigen Tn has been designed, synthesized, and studied for immunological effects. The PS A1 motif was included to act as an MHCII elicitor for a T-cell-dependent immune response with increased immunogenicity against tumor-associated carbohydrate antigens, providing an alternative to carrier proteins. Through the use of C57BL/6 mice, it has been shown that chemical modification of PS A1 does not alter the recognition sequence responsible for an MHCII-mediated, T-cell-dependent immune response. The Tn-PS A1 conjugate construct confers specificity toward the Tn antigen alone, and specific carbohydrate immunoglobulins, namely, IgG3, are generated from intraperitoneal immunizations with or without adjuvant. The properties of the vaccine candidate are attributed to a site-specific linking strategy that incurs significant incorporation of Tn antigen.
- De Silva, Ravindra A.,Wang, Qianli,Chidley, Tristan,Appulage, Dananjaya K.,Andreana, Peter R.
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supporting information; experimental part
p. 9622 - 9623
(2011/03/20)
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- Cowpea mosaic virus capsid: A promising carrier for the development of carbohydrate based antitumor vaccines
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Immunotherapy targeting tumor cell surface carbohydrates is a promising approach for cancer treatment. However, the low immunogenecity of carbohydrates presents a formidable challenge. We describe here the enhancement of carbohydrate immunogenicity by an ordered display on the surface of the cowpea mosaic virus (CPMV) capsid. The Tn glycan, which is overexpressed on numerous cancer cell surfaces, was selected as the model antigen for our study. Previously it has been shown that it is difficult to induce a strong T cell-dependent immune response against the monomeric form of Tn presented in several ways on differeent carriers. In this study, we first synthesized Tn antigens derivatized with either a maleimide or a bromoacetamide moiety that was conjugated selectively to a cysteine mutant of CPMV. The glycoconjugate was then injected into mice and pre- and post-immune antibody levels in the mice sera were measured by enzyme-linked immunosorbant assays. High total antibody titers and, more importantly, high IgG titers specific for Tn were obtained in the post-immune day 35 serum, suggesting the induction of T cell-dependent antibody isotype switching by the glycoconjugate. The antibodies generated were able to recognize Tn antigens presented in their native conformations on the surfaces of both MCF-7 breast cancer cells and the multidrug resistant breast cancer cell line NCI-ADR RES. These results suggest that the CPMV capsid can greatly enhance the immunogenicity of weak antigens such as Tn and this can provide a promising tool for the development of carbohydrate based anti-cancer vaccines.
- Miermont, Adeline,Barnhill, Hannah,Strable, Erica,Lu, Xiaowei,Wall, Katherine A.,Wang, Qian,Finn,Huang, Xuefei
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supporting information; experimental part
p. 4939 - 4947
(2009/04/21)
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- An efficient and improved procedure for preparation of triflyl azide and application in catalytic diazotransfer reaction
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An efficient and improved procedure for preparation of triflyl azide and application in catalytic diazotransfer reaction are described. The amount of highly toxic reagents NaN3 and Tf2O, is significantly reduced comparing with the pr
- Yan, Ri-Bai,Yang, Fan,Wu, Yanfen,Zhang, Li-He,Ye, Xin-Shan
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p. 8993 - 8995
(2007/10/03)
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- Iodine promoted glycosylation with glycosyl iodides: α-glycoside synthesis
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Glycosidation of fully acetylated glucopyranosyl iodide with methanol under the influence of iodine gave α-glucoside selectively. Use of less reactive acceptors led to the formation of α/β-mixtures. Glycosylations with fully benzoylated glucosyl iodide yielded β-glucosides only. In contrast, iodine-promoted glycosylation of serine and threonine with 2-azido-2-deoxy-glycosyl iodides, easily obtained in three steps, proceeded smoothly, resulting in only α-linked products in high yield in most cases. Copyright Taylor & Francis, Inc.
- Van Well, Renate M.,Kartha, K. P. Ravindranathan,Field, Robert A.
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p. 463 - 474
(2007/10/03)
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- Site-specific incorporation of the mucin-type N-acetylgalactosamine- α-O-threonine into protein in Escherichia coli
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Glycosylation is a prevalent posttranslational process capable of augmenting and modulating protein function. Efficient synthesis of high-purity, homogeneous glycoproteins is essential for the study of unique protein glycoforms and for the manufacture of therapeutically relevant forms. A promising new strategy for controlled in vivo synthesis of glycoproteins was recently established using suppressor tRNA technology. Using an evolved tRNA aminoacyl synthetase-tRNA pair from Methanococcus jannaschii, the glycosyl amino acid, N-acetylglucosamine-β-O-serine (GlcNAc-β-Ser), was site-specifically introduced into proteins cotranslationally in Escherichia coli. Herein, we report the evolution of a new tRNA aminoacyl synthetase-tRNA pair that has expanded the repertoire of glycoproteins that can be expressed in E. coli to contain the other major O-linked glycan, N-acetylgalactosamine-α-O-threonine (GalNAc-a-Thr). Copyright
- Xu, Ran,Hanson, Sarah R.,Zhang, Zhiwen,Yang, Yu-Ying,Schultz, Peter G.,Wong, Chi-Huey
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p. 15654 - 15655
(2007/10/03)
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- Chemoenzymatic synthesis of PSGL-1 glycopeptides: Sulfation on tyrosine affects glycosyltransferase-catalyzed synthesis of the O-glycan
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PSGL-1 is the primary glycoprotein ligand for P-selectin during the inflammatory response. Interestingly, the N-terminal sequence, containing both a site of tyrosine sulfation and an O-glycan, has been shown to bind to P-selectin with an affinity similar to full-length PSGL-1. To further characterize this system, the synthesis of glycopeptides from PSGL-1 was undertaken. The synthesis involved both solution- and solid-phase synthesis, as well as enzymatic transformations. During the synthesis, notable reactivity differences of the glycosyltransferases toward sulfated and unsulfated versions of the same glycopeptides were observed. (C) 2000 Elsevier Science Ltd.
- Koeller, Kathryn M.,Smith, Mark E. B.,Wong, Chi-Huey
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p. 1017 - 1025
(2007/10/03)
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- Metal catalyzed diazo transfer for the synthesis of azides from amines
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An improved method for the synthesis of azides is described. Diazo transfer from triflyl azide occurs effectively with Cu++, Ni++, or Zn++ as a catalyst. The process is amenable to scaleup, can be carried out using commerc
- Alper, Phil B.,Hung, Shang-Cheng,Wong, Chi-Huey
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p. 6029 - 6032
(2007/10/03)
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- Convenient Synthesis of 2-Azido-2-deoxy-aldoses by Diazo Transfer
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Diazo transfer from trifluoromethanesulfonyl azide (TfN3) to 2-amino-2-deoxy-glycoses constitutes a high-yielding, simple procedure for the preparation of partially protected or unprotected 2-azido-2-deoxy-aldoses.Thus, the D-allosamine derivative 2 gave
- Vasella, Andrea,Witzig, Christian,Chiara, Jose-Luis,Martin-Lomas, Manuel
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p. 2073 - 2077
(2007/10/02)
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