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1.
We investigated the acceptor substrate specificities of marine bacterial α-(2→3)-sialyltransferase cloned from Photobacterium sp. JT-ISH-224 and α-(2→6)-sialyltransferase cloned from Photobacterium damselae JT0160 using several saccharides as acceptor substrates. After purifying the enzymatic reaction products, we confirmed their structure by NMR spectroscopy. The α-(2→3)-sialyltransferase transferred N-acetylneuraminic acid (Neu5Ac) from cytidine 5′-monophospho-N-acetylneuraminic acid (CMP-Neu5Ac) to the β-anomeric hydroxyl groups of mannose (Man) and α-Manp-(1→6)-Manp, and α-(2→6)-sialyltransferase transferred N-acetylneuraminic acid to the 6-OH groups of the non-reducing end galactose residues in β-Galp-(1→3)-GlcpNAc and β-Galp-(1→6)-GlcpNAc. 相似文献
2.
Dietlind Adlercreutz Bent O. Petersen Norman J. Dovichi 《Carbohydrate research》2010,345(10):1384-1388
Gb3 and iGb3 are physiologically important trihexosylceramides with a terminal α-d-Galp-(1→4)-β-d-Galp- and α-d-Galp-(1→3)-β-d-Galp sequence, respectively. In particular iGb3 is attracting considerable attention as it is believed to serve as a ligand for natural killer T cells. Whether or not iGb3 is present in humans and which enzyme might be responsible for its synthesis is at present a matter of lively debate. In the current investigation we evaluated human blood group B galactosyltransferase (GTB) for its ability to catalyze the formation of iGb3 from lactosylceramide and UDP-Galp. GTB is a retaining glycosyltransferase that in vivo catalyzes the transfer of galactose from UDP-Galp donors to OH-3 of Galp on the H-antigen (α-l-Fucp-(1→2)-β-d-Galp) acceptor forming the blood group B antigen. GTB tolerates modifications in donor and acceptor substrates and its ability to accept lactosides as acceptors makes it a possible candidate for iGb3 production in humans. For comparison iGb3 and Gb3 were also synthesized from the same acceptor using an α-(1→3)- and α-(1→4)-specific galactosyltransferase, respectively. All the enzymes tested catalyzed the desired reactions. Product characterization by NMR analysis clearly differentiated between the α-Galp-(1→3)-Galp and α-Galp-(1→4)-Galp product, with the GTB product being identical to that of the α-(1→3)-GalT-catalyzed reaction. The rate of transfer by GTB however was very low, only 0.001% of the rate obtained with a good substrate, H antigen disaccharide (octyl α-l-Fucp-(1→2)-β-d-Galp). This is too low to account for the possible formation of the iGb3 structure in humans in vivo. 相似文献
3.
Lin Yang 《Carbohydrate research》2010,345(12):1713-14526
The repeating GalpNAc-α-(1→4)-GalpNAc unit is part of a series of essential structures that can be found in many important biomolecules such as the glycoproteins and the O-antigenic polysaccharides of clinically important bacterial strains. In this paper, we describe an exclusive α-selective glycosylation reaction, using a 4,6-di-O-tert-butyldimethylsilyl-N-acetyloxazolidinone-protected thioglycoside as the glycosyl donor, under pre-activation conditions, with only half amount of the promoter, providing the product GalpNAc-α-(1→4)-GalpNAc in high isolated yield. This reaction can be also applied to increasing the length of the repeating structure, which is of significant use in further synthesis of branched or linear oligosaccharides. 相似文献
4.
Synthesis of trisaccharides containing internal galactofuranose O-linked in Trypanosoma cruzi mucins
Verónica M. Mendoza 《Carbohydrate research》2010,345(3):385-2848
The trisaccharides β-d-Galf-(1→2)-β-d-Galf-(1→4)-d-GlcNAc (5) and β-d-Galp-(1→2)-β-d-Galf-(1→4)-d-GlcNAc (6) constitute novel structures isolated as alditols when released by reductive β-elimination from mucins of Trypanosoma cruzi (Tulahuen strain). Trisaccharides 5 and 6 were synthesized employing the aldonolactone approach. Thus, a convenient d-galactono-1,4-lactone derivative was used for the introduction of the internal galactofuranose and the trichloroacetimidate method was employed for glycosylation reactions. Due to the lack of anchimeric assistance on O-2 of the galactofuranosyl precursor, glycosylation studies were performed under different conditions. The nature of the solvent strongly determined the stereochemical course of the glycosylation reactions when the galactofuranosyl donor was substituted either by 2-O-Galp or 2-O-Galf. 相似文献
5.
Lucimara M.C. Cordeiro 《Phytochemistry》2010,71(10):1162-1167
A structural study of the carbohydrates from Coccomyxa mucigena, the symbiotic algal partner of the lichenized fungus Peltigera aphthosa, was carried out. It produced an O-methylated mannogalactan, with a (1 → 6)-linked β-galactopyranose main-chain partially substituted at O-3 by β-Galp, 3-OMe-α-Manp or α-Manp units. There were no similarities with polysaccharides previously found in the lichen thallus of P. aphthosa. Moreover, the influence of lichenization in polysaccharide production by symbiotic microalgae and the nature of the photobiont in carbohydrate production in lichen symbiosis are also discussed. 相似文献
6.
Shearzyme (GH10 endo-1,4-β-d-xylanase) and two different α-l-arabinofuranosidases (AXH-m and AXH-d3) were used stepwise to manufacture arabinoxylo-oligosaccharides (AXOS) with α-l-Araf (1→2)-monosubstituted β-d-Xylp residues or α-l-Araf (1→2)- and (1→3) doubly substituted β-d-Xylp residues from wheat arabinoxylan (AX) in a rather straightforward way. Four major AXOS (d-I, d-II, m-I and m-II) were formed in two separate hydrolyses. The AXOS were purified and the structures were confirmed using TLC, HPAEC-PAD, MALDI-TOF-MS and 1D and 2D NMR spectroscopy. The samples were identified as d-I: α-l-Araf-(1→2)-[α-l-Araf-(1→3)]-β-d-Xylp-(1→4)-β-d-Xylp-(1→4)-d-Xylp, d-II: α-l-Araf-(1→2)-[α-l-Araf-(1→3)]-β-d-Xylp-(1→4)-d-Xylp, m-I: α-l-Araf-(1→2)-β-d-Xylp-(1→4)-β-d-Xylp-(1→4)-d-Xylp and m-II: α-l-Araf-(1→2)-β-d-Xylp-(1→4)-d-Xylp. To our knowledge, this is the first report on structural 1H and 13C NMR analysis of xylobiose-derived AXOS d-II and m-II. The latter compound has not been reported previously. The doubly substituted AXOS were produced for the first time in good yields, as d-I and d-II corresponded to 11.8 and 5.6 wt% of AX, respectively. Singly α-l-Araf (1→2)-substituted AXOS could also be prepared in similar yields by treating the doubly substituted AXOS further with AXH-d3. 相似文献
7.
Mariola Pa?ciak Patricia Sanchez-Carballo Anna Duda-Madej Andrzej Gamian 《Carbohydrate research》2010,345(10):1497-1503
Arthrobacter is a genus of Gram-positive bacteria widely distributed in soil. The ability to catabolize a variety of xenobiotics has shown their potential as a detoxifying agent. Recently, Arthrobacter has been also recognized as an opportunistic pathogen. Glycolipids from A. scleromae, a clinical isolate, and A. globiformis, from soil, were isolated by chloroform-methanol extraction and subsequently purified using column chromatography and high-performance liquid chromatography. Structural studies were carried out utilizing specific chemical degradation, matrix-assisted laser-desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry (MALDI FT ICR-MS), and 1D and 2D nuclear magnetic resonance (NMR) spectroscopy. The major glycolipids in A. scleromae and A. globiformis were found to be a diglycosylglycerol with the structure α-Manp-(1→3)-α-Manp-(1→3)-Gro (Man A-Man B-Gro; G1), and a monoglycosylglycerol with the structure β-Galp-(1→3)-Gro (G2). Glycolipids were acylated at positions 1 of Gro and 6 of Man B in the case of G1 and at positions 1 and 2 of Gro in the case of G2. The distribution of the fatty acids was different in both species. A. scleromae glycolipids contained heptadecanoic acid while in the A. globiformis glycolipids mainly pentadecanoic acid could be detected. The substitution by hexadecanoic acid was proportionally similar in both species. The taxonomical value of major glycolipids from Arthrobacter is also presented. 相似文献
8.
The structure of the O-antigen polysaccharides (PS) from the enteroaggregative Escherichia coli strain 94/D4 and the international type strain E. coli O82 have been determined. Component analysis and 1H, 13C, and 31P NMR spectroscopy experiments were employed to elucidate the structure. Inter-residue correlations were determined by 1H, 13C-heteronuclear multiple-bond correlation, and 1H, 1H-NOESY experiments. d-GroA as a substituent is linked via its O-2 in a phosphodiester-linkage to O-6 of the α-d-Glcp residue. The PS is composed of tetrasaccharide repeating units with the following structure:→4)-α-d-Glcp6-(P-2-d-GroA)-(1→4)-β-d-Galp-(1→4)-β-d-Glcp-(1→3)-β-d-GlcpNAc-(1→Cross-peaks of low intensity from an α-d-Glcp residue were present in the NMR spectra and spectral analysis indicates that they originate from the terminal residue of the polysaccharide. Consequently, the biological repeating unit has a 3-substituted N-acetyl-d-glucosamine residue at its reducing end. Enzyme immunoassay using specific anti-E. coli O82 rabbit sera showed identical reactivity to the LPS of the two strains, in agreement with the structural analysis of their O-antigen polysaccharides. 相似文献
9.
Acceptor products of alternansucrase with gentiobiose. Production of novel oligosaccharides for food and feed and elimination of bitterness 总被引:1,自引:0,他引:1
Gregory L. Côté 《Carbohydrate research》2009,344(2):187-10906
In the presence of suitable acceptor molecules, dextransucrase makes a homologous series of oligosaccharides in which the isomers differ by a single glucosyl unit, whereas alternansucrase synthesizes one trisaccharide, two tetrasaccharides, etc. Previously, we showed that alternansucrase only forms certain isomers of DP > 4 from maltose in measurable amounts, and that these oligosaccharides belong to the oligoalternan series rather than the oligodextran series. We now demonstrate that the acceptor products from gentiobiose, also formed in good yields (nearly 90% in unoptimized reactions), follow a pattern similar to those formed from maltose. The initial product is a single trisaccharide, α-d-Glcp-(1→6)-β-d-Glcp-(1→6)-d-Glc. Two tetrasaccharides were formed in approximately equal quantities: α-d-Glcp-(1→3)-α-d-Glcp-(1→6)-β-d-Glcp-(1→6)-d-Glc and α-d-Glcp-(1→6)-α-d-Glcp-(1→6)-β-d-Glcp-(1→6)-d-Glc. Just one pentasaccharide was isolated from the reaction mixture, α-d-Glcp-(1→6)-α-d-Glcp-(1→3)-α-d-Glcp-(1→6)-β-d-Glcp-(1→6)-d-Glc. Our hypothesis that the enzyme is incapable of forming two consecutive α-(1→3) linkages, and does not form products with more than two consecutive α-(1→6) linkages, apparently applies to other acceptors as well as to maltose. The glucosylation of gentiobiose reduces or eliminates its bitter taste. 相似文献
10.
The O-antigenic polysaccharide of Salmonella Mara O:39 (formerly Q) was investigated by sugar and methylation analyses, absolute configuration assignment, mass spectrometry and NMR spectroscopy. The experiments revealed an O-polysaccharide chain composed of the following linear tetrasaccharide repeating units with the structure:→2)-α-l-Quip3NAc-(1→3)-α-d-Manp-(1→3)-α-l-Fucp-(1→3)-α-d-GalpNAc-(1→where α-l-Quip3NAc is the residue of 3-acetamido-3,6-dideoxy-α-l-glucopyranose. This repeating unit is the first published structure of the O-polysaccharide from 27 serotypes of Salmonella bacteria belonging to serogroup O:39 in the Kauffmann-White classification system. 相似文献
11.
The glucansucrase known as alternansucrase [EC 2.4.1.140] can transfer glucosyl units from sucrose to raffinose to give good yields of oligosaccharides, which may serve as prebiotics. The main products were the tetrasaccharides α-d-Glcp-(1→3)-α-d-Galp-(1→6)-α-d-Glcp-(1↔2)-β-d-Fruf and α-d-Glcp-(1→4)-α-d-Galp-(1→6)-α-d-Glcp-(1↔2)-β-d-Fruf in ratios ranging from 4:1 to 9:1, along with lesser amounts of α-d-Glcp-(1→6)-α-d-Galp-(1→6)-α-d-Glcp-(1↔2)-β-d-Fruf. Ten unusual pentasaccharide structures were isolated. Three of these arose from glucosylation of the major tetrasaccharide product, two each from the minor tetrasaccharides, and three were the result of glucosylations of the fructose acceptor product leucrose or isomaltulose. The major pentasaccharide product arose from glucosylation of the major tetrasaccharide at position 4 of the fructofuranosyl unit, to give a subunit structure analogous to that of maltulose. A number of hexasaccharides and higher oligosaccharides were also produced. Unlike alternansucrase, dextransucrase [EC 2.4.1.5] gave only a single tetrasaccharide product in low yield, and no significant amounts of higher oligosaccharides. The tetrasaccharide structure from dextransucrase was found to be α-d-Glcp-(1→4)-α-d-Galp-(1→6)-α-d-Glcp-(1↔2)-β-d-Fruf, which is at odds with the previously published structure. 相似文献
12.
Junyi YinHuixia Lin Jing LiYuanxing Wang Steve W. Cui Shaoping Nie Mingyong Xie 《Carbohydrate polymers》2012,87(4):2416-2424
In this paper, polysaccharides were extracted from the seeds of Plantago asiatica L. with hot water and separated into three fractions PLP-1 (18.9%), PLP-2 (52.6%) and PLP-3 (28.5%) by Sephacryl™ S-400 HR column chomatography. The main fraction PLP-2's structure was elucidated using oxalic acid hydrolysis, partial acid hydrolysis, methylation, GC, GC-MS, 1D and 2D NMR. PLP-2 was composed of Rha, Ara, Xyl, Man, Glc and Gal, in a molar ratio of 0.05:1.00:1.90:0.05:0.06:0.10. Its uronic acid was GlcA. PLP-2 was highly branched heteroxylan which consisted of a β-1,4-linked Xylp backbone with side chains attached to O-2 or O-3. The side chains consisted of β-T-linked Xylp, α-T-linked Araf, α-T-linked GlcAp, β-Xylp-(1 → 3)-α-Araf and α-Araf-(1 → 3)-β-Xylp, etc. Based on these results, the structure of PLP-2 was proposed. 相似文献
13.
A water-soluble polysaccharide DNP-W2 composed of glucose, mannose, and galactose in the molar ratio of 6.1:2.9:2.0 had been isolated from the stems of Dendrobium nobile. Its molecular weight was 1.8 × 104 Da determined by HPGPC. Structural features of DNP-W2 were investigated by a combination of chemical and instrumental analysis, including FTIR, GC, GC-MS, periodate oxidation-Smith degradation, methylation analysis, partial acid hydrolysis, and NMR spectroscopy. The results showed that DNP-W2 is a 2-O-acetylgalactomannoglucan and has a backbone consisting of (1→4)-linked β-d-Glcp, (1→6)-linked β-d-Glcp, and (1→4)-linked β-d-Manp, with branches at O-6 of (1→4)-linked β-d-Glcp and β-d-Manp. The branches are composed of α-d-Galp. The acetyl groups are substituted at O-2 of (1→4)-linked Manp. Preliminary tests in vitro reveals that DNP-W2 can stimulate ConA- and LPS-induced T and B lymphocyte proliferation. 相似文献
14.
Mikael K.R. Engskog Jianjun Li Mary Deadman Elke K.H. Schweda 《Carbohydrate research》2009,344(5):632-1249
Lipopolysaccharide (LPS) of Haemophilus influenzae comprises a conserved tri-l-glycero-d-manno-heptosyl inner-core moiety (l-α-d-Hepp-(1→2)-[PEtn→6]-l-α-d-Hepp-(1→3)-[β-d-GlcIp-(1→4)]-l-α-d-Hepp-(1→5)-α-Kdop) to which addition of β-d-Glcp to O-4 of GlcI in serotype b strains is controlled by the gene lex2B. In non-typeable H. influenzae strains 1124 and 2019, however, a β-d-Galp is linked to O-4 of GlcI. In order to test the hypothesis that the lex2 locus is involved in the expression of β-d-Galp-(1→4-β-d-Glcp-(1→ from HepI, lex2B was inactivated in strains 1124 and 2019, and LPS glycoform populations from the resulting mutant strains were investigated. Detailed structural analyses using NMR techniques and electrospray-ionisation mass spectrometry (ESIMS) on O-deacylated LPS and core oligosaccharide material (OS), as well as ESIMSn on permethylated dephosphorylated OS, indicated both lex2B mutant strains to express only β-d-Glcp extensions from HepI. This provides strong evidence that Lex2B functions as a galactosyltransferase adding a β-d-Galp to O-4 of GlcI in these strains, indicating that allelic polymorphisms in the lex2B sequence direct alternative functions of the gene product. 相似文献
15.
Andrei V. Perepelov Bin Liu Sof’ya N. Senchenkova Lu Feng Alexander S. Shashkov Yuriy A. Knirel 《Carbohydrate research》2010,345(12):1808-2912
The following structure of the O-polysaccharide (O-antigen) of Salmonella enterica O13 was established by chemical analyses along with 2D 1H and 13C NMR spectroscopy:→2)-α-l-Fucp-(1→2)-β-d-Galp-(1→3)-α-d-GalpNAc-(1→3)-α-d-GlcpNAc-(1→The O-antigen of S. enterica O13 was found to be closely related to that of Escherichia coli O127, which differs only in the presence of a GalNAc residue in place of the GlcNAc residue and O-acetylation. The location of the O-acetyl groups in the E. coli O127 polysaccharide was determined. The structures of the O-polysaccharides studied are in agreement with the DNA sequence of the O-antigen gene clusters of S. enterica O13 and E. coli O127 reported earlier. 相似文献
16.
Evelina L. Zdorovenko Olga A. Valueva Vladimir V. Shubchinskiy Yuriy A. Knirel 《Carbohydrate research》2010,345(12):1812-149
The O-polysaccharide of Pragia fontium 97U116 was obtained by mild acid degradation of the lipopolysaccharide and studied by sugar analysis along with 1D and 2D 1H and 13C NMR spectroscopy. The following structure of the pentasaccharide-repeating unit was established: →2)-α-d-Galf-(1→3)-α-l-Rhap2AcI-(1→4)-α-d-GlcpNAcI-(1→2)-α-l-RhapII-(1→3)-β-d-GlcpNAcII-(1→ 相似文献
17.
β-Galf-(1→5)-β-Galf-(1→6)-α-Manp-(1→6)-α-Manp, the immunodominant epitope in the cell-wall galactomannan of Aspergillus fumigatus, was synthesized for the first time as its allyl glycoside. The key disaccharide glycosyl donor, 2,3,5,6-tetra-O-benzoyl-β-d-galactofuranosyl-(1→5)-2-O-acetyl-3,6-di-O-benzoyl-β-d-galactofuranosyl trichloroacetimidate (10), was constructed by 5-O-glycosylation of 1,2-O-isopropylidene-3,6-di-O-benzoyl-α-d-galactofuranose (4) with 2,3,5,6-tetra-O-benzoyl-β-d-galactofuranosyl trichloroacetimidate (5), followed by 1,2-O-deacetonation, acetylation, selective 1-O-deacetylation, and trichloroacetimidation. The target tetrasaccharide 16 was obtained by the condensation of allyl 2,3,4-tri-O-benzoyl-α-d-mannopyranosyl-(1→6)-2,3,4-tri-O-benzoyl-α-d-mannopyranoside (14) as glycosyl acceptor with the disaccharide glycosyl donor 10, followed by deprotection. 相似文献
18.
Isolation and characterization of poly- and oligosaccharides from the red microalga Porphyridium sp.
The current study forms part of an ongoing research effort focusing on the elucidation of the chemical structure of the sulfated extracellular polysaccharide of the red microalga Porphyridium sp. (UTEX 637). We report here on the chemical structure of a fraction separated from an acidic crude extract of the polysaccharide, as investigated by methylation analysis, carboxyl reduction-methylation analysis, desulfation-methylation analysis, partial acid hydrolysis, Smith degradation, together with 1D and 2D 1H and 13C NMR spectroscopy. This fraction with a molar mass of 2.39 × 105 g mol−1 comprised d- and l-Gal, d-Glc, d-Xyl, d-GlcA, and sulfate groups in a molar ratio of 1.0:1.1:2.1:0.2:0.7. The almost linear backbone of the fraction is composed of (1→2)- or (1→4)-linked d-xylopyranosyl, (1→3)-linked l-galactopyranosyl, (1→3)-linked d-glucopyranosyl, and (1→3)-linked d-glucopyranosyluronic acid and comprises a possible acidic building unit:
[(2 or 4)-β-d-Xylp-(l→3)]m-α-d-Glcp-(1→3)-α-d-GlcpA-(1→3)-l-Galp(l→
Attached to the backbone are sulfate groups and nonreducing terminal d-xylopyranosyl and galactopyranosyl residues, which occur at the O-6 positions of Glc-derived moieties in the main chain. 相似文献19.
Andrei V. Perepelov Bin Liu Sof’ya N. Senchenkova Lu Feng Yuriy A. Knirel 《Carbohydrate research》2010,345(7):971-973
An O-polysaccharide was obtained by mild acid degradation of the lipopolysaccharide of Salmonella enterica O41, and the following structure of the O-unit was determined by chemical analyses along with 1D and 2D 1H and 13C NMR spectroscopy:→2)-β-d-Manp-(1→4)-α-d-Glcp-(1→3)-α-l-QuipNAc-(1→3)-α-d-GlcpNAc-(1→where QuiNAc stands for 2-acetamido-2,6-dideoxyglucose. The structure established is in agreement with the O-antigen gene cluster of S. enterica O41 and tentative assignment of the gene functions reported earlier. 相似文献
20.
Rodríguez-Carvajal MA Sánchez JI Campelo AB Martínez B Rodríguez A Gil-Serrano AM 《Carbohydrate research》2008,343(18):3066-3070
The strain Lactobacillus pentosus LPS26 produces a capsular polymer composed of a high- (2.0 × 106 Da) (EPS A) and a low-molecular mass (2.4 × 104 Da) (EPS B) polysaccharide when grown on semi-defined medium containing glucose as the carbon source. The structure of EPS A and its deacetylated form has been determined by monosaccharide and methylation analysis as well as by 1D/2D NMR studies (1H and 13C). We conclude that EPS A is a charged heteropolymer, with a composition of d-glucose, d-glucuronic acid and l-rhamnose in a molar ratio 1:2:2. The repeating unit is a pentasaccharide with two O-acetyl groups at O-4 of the 3-substituted α-d-glucuronic acid and at O-2 of the 3-substituted β-l-rhamnose, respectively.→4)-α-d-Glcp-(1→3)-α-d-GlcpA4Ac-(1→3)-α-l-Rhap-(1→4)-α-d-GlcpA-(1→3)-β-l-Rhap2Ac-(1→This unbranched structure is not common in EPSs produced by Lactobacilli. Moreover, the presence of acetyl groups in the structure is an unusual feature which has only been reported in L. sake 0-1 [Robijn et al. Carbohydr. Res., 1995, 276, 117-136]. 相似文献