- A unified strategy for the synthesis of mucin cores 1-4 saccharides and the assembled multivalent glycopeptides
-
By displaying different O-glycans in a multivalent mode, mucin and mucin-like glycoproteins are involved in a plethora of protein binding events. The understanding of the roles of the glycans and the identification of potential glycan binding proteins are major challenges. To enable future binding studies of mucin glycan and glycopeptide probes, a method that gives flexible and efficient access to all common mucin core-glycosylated amino acids was developed. Based on a convergent synthesis strategy starting from a shared early stage intermediate by differentiation in the glycoside acceptor reactivity, a common disaccharide building block allows for the creation of extended glycosylated amino acids carrying the mucin type-2 cores 1-4 saccharides. Formation of a phenyl-sulfenyl-N-Troc (Troc=trichloroethoxycarbonyl) byproduct during N-iodosuccinimide-promoted thioglycoside couplings was further characterized and a new methodology for the removal of the Troc group is described. The obtained glycosylated 9-fluorenylmethoxycarbonyl (Fmoc)-protected amino acid building blocks are incorporated into peptides for multivalent glycan display. One for all! In a convergent approach starting from a shared early-stage intermediate by differentiation in the glycoside acceptor reactivity, a common disaccharide building block allows for the creation of extended glycosylated amino acids carrying the mucin type-2 cores 1-4 saccharides (see scheme). The amino acids are incorporated into peptides for multivalent glycan display. Ac=acetyl, Troc=trichloroethoxycarbonyl, TBS=tert-butyl dimethylsilyl
- Pett, Christian,Schorlemer, Manuel,Westerlind, Ulrika
-
-
Read Online
- Synthesis and protein binding studies of a peptide fragment of clathrin assembly protein AP180 bearing an O-linked β-N-acetylglucosaminyl-6- phosphate modification
-
A novel post-translational modification of threonine, β-N- acetylglucosaminyl-phosphate, was recently discovered on assembly protein AP180, a protein which plays a crucial role in clathrin coated vesicle formation in synaptic vesicle endocytosis (SVE). Herein, we report studies aimed at probing the effect of this modification on binding to proteins in rat brain lysate using pull down experiments with peptide fragments of AP180. The Royal Society of Chemistry 2012.
- Graham, Mark E.,Stone, Robin S.,Robinson, Phillip J.,Payne, Richard J.
-
-
Read Online
- Simplified beta-glycosylation of peptides
-
A simple and effective activating system for S-phenyl thioglycosides, namely N-iodosuccinimide and catalytic copper(I) triflate, promotes beta-O-glycosylation at the serine and threonine hydroxyls of “mono-,” di-, and tripeptides. The same activator combination promotes carboxamide beta-N-glycosylation of asparagine-containing mono-, di, and tri-peptides, as well as a nucleoside carboxamide and a sulfonamide. An important feature of the copper(I) triflate method is that undesired amide O-glycosylation is largely circumvented. For both sets of biologically important acceptor sites (HO– and –CONH2), a beta-GlcNAc-equivalent donor is demonstrated to provide the linkages efficiently. Streamlined deprotection sequences have been developed based on global hydrogenolysis that lead smoothly to the parent glycopeptides. The core glycopeptide region for biological protein N-glycosylation, represented by N4-(β-N-acetyl-D-2-glucosaminyl)-Asp-Gly-Thr-OH, has been prepared in solution, purified, and characterized as the fully deprotected (mono)glycosylated tripeptide.
- Zhang, Yonglian,Knapp, Spencer
-
p. 2891 - 2903
(2018/05/08)
-
- Synthesis of LewisX-O-Core-1 threonine: A building block for O-linked LewisX glycopeptides
-
LewisX (LeX) is a branched trisaccharide Galβ1→4(Fucα1→3)GlcNAc that is expressed on many cell surface glycoproteins and plays critical roles in innate and adaptive immune responses. However, efficient synthesis of glycopeptides bearing LeX remains a major limitation for structure-function studies of the LeX determinant. Here we report a total synthesis of a LeX pentasaccharide 1 using a regioselective 1-benzenesulfinyl piperidine/triflic anhydride promoted [3 + 2] glycosylation. The presence of an Fmoc-threonine amino acid facilitates incorporation of the pentasaccharide in solid phase peptide synthesis, providing a route to diverse O-linked LeX glycopeptides. The described approach is broadly applicable to the synthesis of a variety of complex glycopeptides containing O-linked LeX or sialyl LewisX (sLeX).
- Sardar, Mohammed Y.R.,Krishnamurthy, Venkata R.,Park, Simon,Mandhapati, Appi Reddy,Wever, Walter J.,Park, Dayoung,Cummings, Richard D.,Chaikof, Elliot L.
-
-
- A 3,4-trans-fused cyclic protecting group facilitates α-selective catalytic synthesis of 2-deoxyglycosides
-
A practical approach has been developed to convert glucals and rhamnals into disaccharides or glycoconjugates with high α-selectivity and yields (77-97 %) using a trans-fused cyclic 3,4-O-disiloxane protecting group and TsOH·H2O (1 mol %) as a catalyst. Control of the anomeric selectivity arises from conformational locking of the intermediate oxacarbenium cation. Glucals outperform rhamnals because the C6 side-chain conformation augments the selectivity.
- Balmond, Edward I.,Benito-Alifonso, David,Coe, Diane M.,Alder, Roger W.,McGarrigle, Eoghan M.,Galan, M. Carmen
-
p. 8190 - 8194
(2014/08/18)
-
- Design and synthesis of a novel ganglioside ligand for influenza a viruses
-
A novel ganglioside bearing Neuα2-3Gal and Neuα2-6Gal structures as distal sequences was designed as a ligand for influenza A viruses. The efficient synthesis of the designed ganglioside was accomplished by employing the cassette coupling approach as a ke
- Nohara, Tomohiro,Imamura, Akihiro,Yamaguchi, Maho,Hidari, Kazuya I.P.J.,Suzuki, Takashi,Komori, Tatsuya,Ando, Hiromune,Ishida, Hideharu,Kiso, Makoto
-
p. 9590 - 9620
(2012/11/07)
-
- Protecting group-free glycoligation by the desulfurative rearrangement of allylic disulfides as a means of assembly of oligosaccharide mimetics
-
2-(2-Pyridyldithio-3-butenyl) glycosides react with carbohydrate-based thiols in a two-step process involving sulfenyl transfer followed by desulfurative 2,3-allylic rearrangement, promoted by either triphenylphosphine or silver nitrate, to give novel saccharide mimetics. In an alternative embodiment of the same chemistry anomeric thiols are coupled with carbohydrates derivatized in the form of 2-(2-pyridyldithio-3-butenyl) ethers. This new method of glycoligation does not require protection of hydroxyl groups and is compatible with the presence of acetamides, azides, trichloroethoxycarbamates, and thioglycosides. Variations on the general theme enable the preparation of mimetics of reducing and nonreducing oligosaccharides as well as of nonglycosidically linked systems.
- Subramanian, Venkataraman,Moume-Pymbock, Myriame,Hu, Tianshun,Crich, David
-
p. 3691 - 3709
(2011/06/25)
-
- Chemoselective deprotection of acid labile primary hydroxyl protecting groups under CBr4-photoirradiation conditions
-
The CBr4-photoirradiation in methanol generates a controlled source of HBr, which can chemoselectively deprotect commonly used hydroxyl-protecting groups in saccharides and nucleosides, such as tert-butyldimethylsilyl, isopropylidene, benzylidene and triphenyl ethers in the presence of other acid-labile functional groups. Graphical Abstract.
- Chen, Ming-Yi,Patkar, Laxmikant N.,Lu, Kuo-Cheng,Lee, Adam Shih-Yuan,Lin, Chun-Cheng
-
p. 11465 - 11475
(2007/10/03)
-
- CBr4-photoirradiation protocol for chemoselective deprotection of acid labile primary hydroxyl protecting groups
-
CBr4-photoirradiation protocol was found to be a mild, highly efficient and selective method for deprotection of isopropylidene, benzylidene, triphenylmethyl and tert-butyldimethylsilyl protecting groups on sugar molecules. The conditions of this reaction can also be used to cleave peptides off from acid-labile resin linkers in solid-phase peptide synthesis.
- Chen, Ming-Yi,Patkar, Laxmikant N.,Jan, Mi-Dan,Lee, Adam Shih-Yuan,Lin, Chun-Cheng
-
p. 635 - 639
(2007/10/03)
-
- Simplifying oligosaccharide synthesis: Efficient synthesis of lactosamine and siaylated lactosamine oligosaccharide donors
-
A practical sequence is described for converting D-glucosamine into peracetylated Gal(β-1,4)-GlcNTroc(β1-S)Ph and Neu5Ac(α-2,3)Gal(β-1,4)GlcNTroc(β1-S)Ph building blocks using a synthetic strategy based on chemoenzymatic oligosaccharide synthesis. The known trichloroethoxycarbonyl, N-Troc, protecting group was selected as a suitable protecting group for both enzymatic and chemical reaction conditions. These oligosaccharide building blocks proved effective donors for the β-selective glycosylation of the unreactive OH-3 of a polymeric PEG-bound acceptor and for the axial OH-2 of a mannose acceptor in good yields. The resulting complex oligosaccharides are useful for vaccine and pharmaceutical applications.
- Yan, Fengyang,Mehta, Seema,Eichler, Eva,Wakarchuk, Warren W.,Gilbert, Michel,Schur, Melissa J.,Whitfield, Dennis M.
-
p. 2426 - 2431
(2007/10/03)
-
- Lipid A and related compounds. XXXII. Synthesis of biologically active N-acylated L-homoserine-containing D-glucosamine-4-phosphate derivatives structurally related to lipid A
-
New N-acylated L-homoserine-containing non-phosphorylated and phosphorylated D-glucosamine derivatives were synthesized as mimicks of lipid A disaccharide. Some of the synthesized compounds exhibited mitogenic activity and nitric oxide (NO) productivity.
- Miyajima, Keisuke,Achiwa, Kazuo
-
p. 312 - 320
(2007/10/03)
-