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Kazuyuki Sugahara - One of the best experts on this subject based on the ideXlab platform.
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structural determination of five novel Tetrasaccharides containing 3 o sulfated d glucuronic acid and two rare oligosaccharides containing a β d glucose branch isolated from squid cartilage chondroitin sulfate e
Biochemistry, 2004Co-Authors: Akiko Kinoshitatoyoda, Shuhei Yamada, Stuart M Haslam, Kayhooi Khoo, Makiko Sugiura, Howard R Morris, A Dell, Kazuyuki SugaharaAbstract:Oversulfated chondroitin sulfate E (CS-E) derived from squid cartilage exhibits intriguing biological activities, which appear to reflect the biological activities of mammalian CS chains containing the so-called E disaccharide unit [GlcAβ1-3GalNAc(4,6-O-disulfate)]. Previously, we isolated novel tetra- and hexasaccharides containing a rare GlcA(3-O-sulfate) at the nonreducing end after digestion of squid cartilage CS-E with testicular hyaluronidase. In this study, squid cartilage CS-E was extensively digested with chondroitinase AC-II, which yielded five highly sulfated novel Tetrasaccharides and two odd-numbered oligosaccharides (tri- and pentasaccharides) containing d-Glc. Their structures were determined by fast atom bombardment mass spectrometry and 1H NMR spectroscopy. The results revealed an internal GlcA(3-O-sulfate) residue for all the novel tetrasaccharide sequences, which rendered the oligosaccharides resistant to the enzyme. The results suggest that GlcA(3-O-sulfate) units are not clustered but...
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novel Tetrasaccharides isolated from squid cartilage chondroitin sulfate e contain unusual sulfated disaccharide units glca 3 o sulfate beta1 3galnac 6 o sulfate or glca 3 o sulfate beta1 3galnac
Journal of Biological Chemistry, 1997Co-Authors: Akiko Kinoshita, Shuhei Yamada, Stuart M Haslam, Howard R Morris, A Dell, Kazuyuki SugaharaAbstract:Abstract We previously isolated novel Tetrasaccharides containing 3-O-sulfated glucuronic acid from king crab cartilage chondroitin sulfate K and demonstrated that the disaccharide units containing 3-O-sulfated glucuronic acid were decomposed by chondroitinase ABC digestion (Sugahara, K., Tanaka, Y., Yamada, S., Seno, N., Kitagawa, H., Haslam, S. M., Morris, H. R., and Dell, A. (1996) J. Biol. Chem. 271, 26745–26754). The findings indicated the necessity to re-evaluate the disaccharide compositions of chondroitin sulfate preparations purified from other biological sources and analyzed using the above enzyme. In this study, to evaluate squid cartilage chondroitin sulfate E a series of even-numbered oligosaccharides were isolated after exhaustive digestion with sheep testicular hyaluronidase and subsequent fractionation by gel chromatography. The tetrasaccharide fraction was subfractionated by high performance liquid chromatography on an amine-bound silica column. Systematic structural analysis of five major fractions, h,l, m, n, and q, by fast atom bombardment mass spectrometry, enzymatic digestions in conjunction with capillary electrophoresis, and 500-MHz 1H NMR spectroscopy revealed one disulfated, three trisulfated, and one tetrasulfated tetrasaccharide structure: fraction h, GlcAβ1–3GalNAc(4S)β1–4GlcAβ1–3GalNAc(4S); fractionl, GlcA(3S)β1–3GalNAc(6S)β1–4GlcAβ1–3GalNAc(4S); fractionm, GlcA(3S)β1–3GalNAc(4S)β1–4GlcAβ1–3GalNAc(4S); fractionn, GlcAβ1–3GalNAc(4S,6S)β1–4GlcAβ1–3GalNAc(4S); and fraction q, GlcA(3S)β1–3GalNAc(4S,6S)β1–4GlcAβ1–3GalNAc(4S), where 3S, 4S, and 6S represent 3-O-, 4-O- and 6-O-sulfate, respectively. The structures found in fractions h and m as well as the unsaturated counterpart of that found in fraction n have been reported, whereas those in fractions l and q are novel in that they contained unusual disulfated and trisulfated disaccharide units where GlcA(3S) is directly linked to GalNAc(6S) and GalNAc(4S,6S), respectively. These novel tetrasaccharide sequences are distinct from those found in other chondroitin sulfate isoforms and may play key roles in the biological functions and activities of chondroitin sulfate E not only from squid cartilage but also from mammalian cells and tissues.
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Assessment of glycosaminoglycan-protein linkage Tetrasaccharides as acceptors for GalNAc- and GlcNAc-transferases from mouse mastocytoma.
Glycoconjugate journal, 1997Co-Authors: Kerstin Lidholt, Tomoya Ogawa, Maria Fjelstad, Ulf Lindahl, Fumitaka Goto, Hiroshi Kitagawa, Kazuyuki SugaharaAbstract:Two glycosaminoglycan-protein linkage tetrasaccharide-serine compounds, GlcAβ1-3Galβ1-3Galβ1-4Xylβ1-O-Ser and GlcAβ1-3Gal(4-O-sulfate)β1-3Galβ1-4Xylβ1-O-Ser, were tested as hexosamine acceptors, using UDP-[3H]GlcNAc and UDP-[3H]GalNAc as sugar donors, and solubilized mouse mastocytoma microsomes as enzyme source. The nonsulfated Ser-tetrasaccharide was found to function as an acceptor for a GalNAc residue, whereas the Ser-tetrasaccharide containing a sulfated galactose unit was inactive. Characterization of the radio-labelled product by digestion with α-N-acetylgalactosaminidase and β-N-acetylhexosaminidase revealed that the [3H]GalNAc unit was α-linked, as in the product previously synthesized using serum enzymes, and not β-linked as found in the chondroitin sulfate polymer. Heparan sulfate/heparin biosynthesis could not be primed by either of the two linkage Ser-Tetrasaccharides, since no transfer of [3H]GlcNAc from UDP-[3H]GlcNAc could be detected. By contrast, transfer of a [3H]GlcNAc unit to a [GlcAβ1-4GlcNAcα1-4]2-GlcAβ1-4-aMan hexasaccharide acceptor used to assay the GlcNAc transferase involved in chain elongation, was readily detected. These results are in agreement with the recent proposal that two different N-acetylglucosaminyl transferases catalyse the biosynthesis of heparan sulfate. Although the mastocytoma system contains both the heparan sulfate/heparin and chondroitin sulfate biosynthetic enzymes the Ser-Tetrasaccharides do not seem to fulfil the requirements to serve as acceptors for the first HexNAc transfer reactions involved in the formation of these polysaccharides.
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preparation of a series of sulfated Tetrasaccharides from shark cartilage chondroitin sulfate d using testicular hyaluronidase and structure determination by 500 mhz1h nmr spectroscopy
Glycoconjugate Journal, 1996Co-Authors: Kazuyuki Sugahara, Yukako Tanaka, Shuhei YamadaAbstract:Six tetrasaccharide fractions were isolated from shark cartilage chondroitin sulfate D by gel filtration chromatography followed by HPLC on an amine-bound silica column after exhaustive digestion with testicular hyaluronidase. Their structures were determined unambiguously by one- and two-dimensional 500 MHz1H NMR spectroscopy in conjunction with HPLC analysis of chondroitinase AC-II digests of the Tetrasaccharides. One fraction was found to contain two tetrasaccharide components. All the seven Tetrasaccharides shared the common core structure GlcAβ1-3GalNAcβ1-4GlcAβ1-3GalNAc with various sulfation profiles. Four were disulfated comprising of two monosulfated disaccharide units GlcAβ1-3GalNAc(4-sulfate) and/or GlcAβ1-3GalNAc(6-sulfate), whereas the other three were hitherto unreported trisulfated Tetrasaccharides containing a disulfated disaccharide unit GlcA(2-sulfate)β1-3GalNAc(6-sulfate) and a monosulfated disaccharide unit GlcAβ1-3GalNAc(4-or 6-sulfate). These sulfated Tetrasaccharides were demonstrated to serve as appropriate acceptor substrates for serum α-N-acetylgalactosaminyltransferase, indicating their usefulness as authentic oligosaccharide substrates or probes for the glycobiology of sulfated glycosaminoglycans.
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Structural Analysis of Unsaturated Hexasaccharides Isolated from Shark Cartilage Chondroitin Sulfate D that are Substrates for the Exolytic Action of Chondroitin ABC Lyase
European Journal of Biochemistry, 1996Co-Authors: Kazuyuki Sugahara, Satomi Nadanaka, Kyoko Takeda, Takeshi KojimaAbstract:The enzymatic action of highly purified chondroitin ABC lyase from Proteus vulgaris is dependent on the size of the substrate, and the enzyme does not cleave Tetrasaccharides, irrespective of their sulfation profiles [Sugahara, K., Shigeno, K., Masuda, M., Fujii, N., Kurosaka, A. & Takeda, K. (1994) Carbohydr: Res. 255, 145–163]. To characterize the enzyme action in more detail, we isolated nine sulfated hexasaccharides from commercial shark cartilage chondroitin sulfate D, after partial digestion with highly purified chondroitin ABC lyase, by means of gel chromatography and HPLC on an amine-bound silica column. Structural analysis by 500-MHz 1H-NMR spectroscopy, and enzymatic digestion in conjunction with HPLC, demonstrated that these hexasaccharides, with the common core saccharide structure ?4HexA(α1-3)-GalNAc(βl-4)GlcA(β1-3)GalNAc(β1-4)GlcA(β1-3)GalNAc (where ?4HexA and GlcA represent 4-deoxy-α-l-threa-hex-4-enepyranosyluronic acid and glucuronic acid, respectively) bear three or four sulfate groups in different combinations. In the hexasaccharides, the D disaccharide unit GlcA2-SO3−(β1-3)GalNAc6SO3−, which is characteristic of chondroitin sulfate D, was arranged on the reducing side of the A disaccharide unit GlcA(βl-3)GalNAc4SO3−, and thus formed an A-D tetrasaccharide sequence GIcA(β1-3)GalNAc4SO3−(β1-4)GlcA2SO–(β1-3)GalNAc6SO3−. Analysis of the degradation products of these hexasaccharides with highly purified chondroitin ABC lyase indicated that the enzyme preferentially acted on the unsaturated hexasaccharides in an exolytic fashion and removed an unsaturated disaccharide unit from the non-reducing termini, irrespective of the sulfation profiles of the hexasaccharides.
Anup Kumar Misra - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of the tetrasaccharide repeating unit of the O-antigen of the Escherichia coli O69 strain and its conformational analysis
RSC Adv., 2014Co-Authors: Manas Jana, Rajiv K. Kar, Anirban Bhunia, Anup Kumar MisraAbstract:A straightforward synthesis of the tetrasaccharide repeating unit of the O-antigen of the Escherichia coli O69 strain as its 2-aminoethyl glycoside has been accomplished by carrying out two iterative glycosylations in one pot. The stereochemical outcome of the glycosylations was very good. The conformational analysis of the synthesized tetrasaccharide was carried out using NOE based two-dimensional ROESY spectroscopy in conjugation with all atom explicit molecular dynamics simulation studies. The solvent-perturbation induced conformations of the tetrasaccharide 1 were found quite stable in solution.
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expedient synthesis of two structurally close Tetrasaccharides corresponding to the o antigens of escherichia coli o127 and salmonella enterica o13
Tetrahedron-asymmetry, 2012Co-Authors: Abhishek Santra, Tamashree Ghosh, Anup Kumar MisraAbstract:Abstract Two structurally close Tetrasaccharides corresponding to the O-antigens of Escherichia coli O127 and Salmonella enterica O13 have been synthesized using a ‘unichemo’ approach and minimum number of reaction steps. The yields of all glycosylation steps were excellent with a high stereochemical outcome. A common synthetic strategy has been adopted for the simultaneous synthesis of two Tetrasaccharides.
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Synthesis of the Tetrasaccharide Motif and Its Structural Analog Corresponding to the Lipopolysaccharide of Escherichia coli O75
2012Co-Authors: Abhijit Sau, Anup Kumar MisraAbstract:BackgroundExtraintestinal pathogenic E. coli are mostly responsible for a diverse spectrum of invasive human and animal infections leading to the urinary tract infections. Bacterial lipopolysaccharides are responsible for their pathogenicity and their interactions with host immune responses. In spite of several breakthroughs in the development of therapeutics to combat urinary tract infections and related diseases, the emergence of multidrug-resistant bacterial strains is a serious concern. Lipopolysaccharides are attractive targets for the development of long-term therapeutic agents to eradicate the infections. Since the natural sources cannot provide the required amount of oligosaccharides, development of chemical synthetic strategies for their synthesis is relevant to gain access to a reservoir of oligosaccharides and their close analogs. MethodologyTwo tetrasaccharide derivatives were synthesized from a single disaccharide intermediate. β-d-mannoside moiety was prepared from β-d-glucoside moiety following oxidation–reduction methodology. A [2+2] stereoselective block glycosylation strategy has been adopted for the preparation of tetrasaccharide derivative. α-d-Glucosamine moiety was prepared from α-d-mannosidic moiety following triflate formation at C-2 and SN2 substitution. A one-pot iterative glycosylation exploiting the orthogonal property of thioglycoside was carried out during the synthesis of tetrasaccharide analog. ResultsSynthesis of the tetrasaccharide motif (1) and its structural analog (2) corresponding to the lipopolysaccharide of Escherichia coli O75 was successfully achieved in excellent yield. Most of the reactions are clean and high yielding. Both compounds 1 and 2 were synthesized as their 4-methoxyphenyl glycoside, which can act as a temporary anomeric protecting group for further use of these Tetrasaccharides in the preparation of glycoconjugates.
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Convergent synthesis of the tetrasaccharide repeating unit corresponding to the O-antigen of the verotoxin-producing Escherichia coli O176
Glycoconjugate Journal, 2011Co-Authors: Goutam Guchhait, Anup Kumar MisraAbstract:A convergent synthesis of the tetrasaccharide repeating unit of the O -antigen of the verotoxin producing E. coli O176 has been achieved in excellent yield adopting a [2 + 2] block glycosylation strategy. The β-D-mannosidic moiety of the tetrasaccharide was prepared from β-D-glucoside and α-D-galactosamine moiety was derived from D-galactal. The tetrasaccharide was synthesized as its 2-trimethylsilylethyl glycoside in excellent yield. All intermediate steps are high yielding. Figure A convergent synthetic strategy of the tetrasaccharide repeating unit corresponding to the O -antigen of verotoxin-producing Escherichia coli has been successfully developed using stereoselective [2 + 2] block glycosylation technique.
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Convergent synthesis of the tetrasaccharide repeating unit corresponding to the O-antigen of the verotoxin-producing Escherichia coli O176
Glycoconjugate Journal, 2011Co-Authors: Goutam Guchhait, Anup Kumar MisraAbstract:A convergent synthesis of the tetrasaccharide repeating unit of the O -antigen of the verotoxin producing E. coli O176 has been achieved in excellent yield adopting a [2 + 2] block glycosylation strategy. The β-D-mannosidic moiety of the tetrasaccharide was prepared from β-D-glucoside and α-D-galactosamine moiety was derived from D-galactal. The tetrasaccharide was synthesized as its 2-trimethylsilylethyl glycoside in excellent yield. All intermediate steps are high yielding. Figure A convergent synthetic strategy of the tetrasaccharide repeating unit corresponding to the O -antigen of verotoxin-producing Escherichia coli has been successfully developed using stereoselective [2 + 2] block glycosylation technique.
Shuhei Yamada - One of the best experts on this subject based on the ideXlab platform.
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structural determination of five novel Tetrasaccharides containing 3 o sulfated d glucuronic acid and two rare oligosaccharides containing a β d glucose branch isolated from squid cartilage chondroitin sulfate e
Biochemistry, 2004Co-Authors: Akiko Kinoshitatoyoda, Shuhei Yamada, Stuart M Haslam, Kayhooi Khoo, Makiko Sugiura, Howard R Morris, A Dell, Kazuyuki SugaharaAbstract:Oversulfated chondroitin sulfate E (CS-E) derived from squid cartilage exhibits intriguing biological activities, which appear to reflect the biological activities of mammalian CS chains containing the so-called E disaccharide unit [GlcAβ1-3GalNAc(4,6-O-disulfate)]. Previously, we isolated novel tetra- and hexasaccharides containing a rare GlcA(3-O-sulfate) at the nonreducing end after digestion of squid cartilage CS-E with testicular hyaluronidase. In this study, squid cartilage CS-E was extensively digested with chondroitinase AC-II, which yielded five highly sulfated novel Tetrasaccharides and two odd-numbered oligosaccharides (tri- and pentasaccharides) containing d-Glc. Their structures were determined by fast atom bombardment mass spectrometry and 1H NMR spectroscopy. The results revealed an internal GlcA(3-O-sulfate) residue for all the novel tetrasaccharide sequences, which rendered the oligosaccharides resistant to the enzyme. The results suggest that GlcA(3-O-sulfate) units are not clustered but...
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novel Tetrasaccharides isolated from squid cartilage chondroitin sulfate e contain unusual sulfated disaccharide units glca 3 o sulfate beta1 3galnac 6 o sulfate or glca 3 o sulfate beta1 3galnac
Journal of Biological Chemistry, 1997Co-Authors: Akiko Kinoshita, Shuhei Yamada, Stuart M Haslam, Howard R Morris, A Dell, Kazuyuki SugaharaAbstract:Abstract We previously isolated novel Tetrasaccharides containing 3-O-sulfated glucuronic acid from king crab cartilage chondroitin sulfate K and demonstrated that the disaccharide units containing 3-O-sulfated glucuronic acid were decomposed by chondroitinase ABC digestion (Sugahara, K., Tanaka, Y., Yamada, S., Seno, N., Kitagawa, H., Haslam, S. M., Morris, H. R., and Dell, A. (1996) J. Biol. Chem. 271, 26745–26754). The findings indicated the necessity to re-evaluate the disaccharide compositions of chondroitin sulfate preparations purified from other biological sources and analyzed using the above enzyme. In this study, to evaluate squid cartilage chondroitin sulfate E a series of even-numbered oligosaccharides were isolated after exhaustive digestion with sheep testicular hyaluronidase and subsequent fractionation by gel chromatography. The tetrasaccharide fraction was subfractionated by high performance liquid chromatography on an amine-bound silica column. Systematic structural analysis of five major fractions, h,l, m, n, and q, by fast atom bombardment mass spectrometry, enzymatic digestions in conjunction with capillary electrophoresis, and 500-MHz 1H NMR spectroscopy revealed one disulfated, three trisulfated, and one tetrasulfated tetrasaccharide structure: fraction h, GlcAβ1–3GalNAc(4S)β1–4GlcAβ1–3GalNAc(4S); fractionl, GlcA(3S)β1–3GalNAc(6S)β1–4GlcAβ1–3GalNAc(4S); fractionm, GlcA(3S)β1–3GalNAc(4S)β1–4GlcAβ1–3GalNAc(4S); fractionn, GlcAβ1–3GalNAc(4S,6S)β1–4GlcAβ1–3GalNAc(4S); and fraction q, GlcA(3S)β1–3GalNAc(4S,6S)β1–4GlcAβ1–3GalNAc(4S), where 3S, 4S, and 6S represent 3-O-, 4-O- and 6-O-sulfate, respectively. The structures found in fractions h and m as well as the unsaturated counterpart of that found in fraction n have been reported, whereas those in fractions l and q are novel in that they contained unusual disulfated and trisulfated disaccharide units where GlcA(3S) is directly linked to GalNAc(6S) and GalNAc(4S,6S), respectively. These novel tetrasaccharide sequences are distinct from those found in other chondroitin sulfate isoforms and may play key roles in the biological functions and activities of chondroitin sulfate E not only from squid cartilage but also from mammalian cells and tissues.
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preparation of a series of sulfated Tetrasaccharides from shark cartilage chondroitin sulfate d using testicular hyaluronidase and structure determination by 500 mhz1h nmr spectroscopy
Glycoconjugate Journal, 1996Co-Authors: Kazuyuki Sugahara, Yukako Tanaka, Shuhei YamadaAbstract:Six tetrasaccharide fractions were isolated from shark cartilage chondroitin sulfate D by gel filtration chromatography followed by HPLC on an amine-bound silica column after exhaustive digestion with testicular hyaluronidase. Their structures were determined unambiguously by one- and two-dimensional 500 MHz1H NMR spectroscopy in conjunction with HPLC analysis of chondroitinase AC-II digests of the Tetrasaccharides. One fraction was found to contain two tetrasaccharide components. All the seven Tetrasaccharides shared the common core structure GlcAβ1-3GalNAcβ1-4GlcAβ1-3GalNAc with various sulfation profiles. Four were disulfated comprising of two monosulfated disaccharide units GlcAβ1-3GalNAc(4-sulfate) and/or GlcAβ1-3GalNAc(6-sulfate), whereas the other three were hitherto unreported trisulfated Tetrasaccharides containing a disulfated disaccharide unit GlcA(2-sulfate)β1-3GalNAc(6-sulfate) and a monosulfated disaccharide unit GlcAβ1-3GalNAc(4-or 6-sulfate). These sulfated Tetrasaccharides were demonstrated to serve as appropriate acceptor substrates for serum α-N-acetylgalactosaminyltransferase, indicating their usefulness as authentic oligosaccharide substrates or probes for the glycobiology of sulfated glycosaminoglycans.
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isolation of the porcine heparin Tetrasaccharides with glucuronate 2 o sulfate heparinase cleaves glucuronate 2 o sulfate containing disaccharides in highly sulfated blocks in heparin
Journal of Biological Chemistry, 1995Co-Authors: Shuhei Yamada, Tomoko Murakami, Hiromi Tsuda, Keiichi Yoshida, Kazuyuki SugaharaAbstract:Eleven Tetrasaccharides were isolated from the repeating disaccharide region of porcine intestinal heparin after strong digestion with Flavobacterium heparinase. Their structures were determined by composition analysis, enzymatic analysis, and 1H NMR spectroscopy. Nine of them have the common tetrasaccharide backbone, delta HexA alpha 1-4GlcN alpha 1-4IdoA alpha 1-4GlcN, where delta HexA and IdoA represent 4,5-unsaturated hexuronic acid and L-iduronic acid, respectively, and their structural variations are based upon the positions of sulfate groups. The nine compounds include one hexasulfated, three pentasulfated and five tetrasulfated compounds, and four of them have not been isolated previously as discrete structures. The other two of the 11 Tetrasaccharides have the following hitherto unreported structures with novel glucuronate 2-O-sulfate at the internal position: delta HexA(2-sulfate) alpha 1- 4GlcN(N,6-disulfate) alpha 1-4GlcA(2-sulfate) beta 1-4GlcN(N-sulfate) and delta HexA(2-sulfate) alpha 1-4GlcN(N,6-disulfate) alpha 1-4GlcA(2-sulfate) beta 1-4GlcN(N,6-disulfate). Thus, 2-O-sulfated glucuronate in the highly sulfated tetrasaccharide structures typical of heparin has been demonstrated. The former and the latter Tetrasaccharides account for 0.31 and 0.32% (w/w) of the starting heparin, respectively. Their yield, however, is an underestimation, since these tetrasaccharide structures in longer sequences will be degraded by heparinase. Although the latter tetrasaccharide described above was unexpectedly cleaved by heparinase into two disaccharide units, the former was not degraded by the enzyme most likely due to the lack of the 6-O-sulfate group on the GlcN residue at the reducing terminus. The results indicate its capability of catalyzing both anti and syn elimination, a property shared by heparitinases I and II and chondroitinase ABC. Both Tetrasaccharides were degraded into disaccharides by heparitinase II. Therefore, it is necessary to reevaluate the disaccharide composition of heparin/heparan sulfate or oligosaccharide structures, which were previously determined after heparinase or heparitinase II digestion. It is no longer possible to conclude that the 2-O-sulfated unsaturated uronic acid residues obtained from heparin/heparan sulfate by lyase digestions are always derived from iduronate 2-O-sulfate residues in the original polymer. It is quite possible that the novel glucuronate 2-O-sulfate structure in the highly sulfated region of heparin is involved in some of the biological activities of heparin.
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structural studies on the bacterial lyase resistant Tetrasaccharides derived from the antithrombin iii binding site of porcine intestinal heparin
Journal of Biological Chemistry, 1993Co-Authors: Shuhei Yamada, Kazuyuki Sugahara, Keiichi Yoshida, Kayhooi Khoo, Makiko Sugiura, Howard R Morris, A DellAbstract:Abstract Three discrete tetrasaccharide structures which are resistant to Flavobacterium heparinase and heparitinases I and II were isolated from porcine intestinal heparin after exhaustive digestion with a mixture of all the above enzymes, and the tri-, tetra-, and penta-sulfated structures were determined by negative ion mode fast atom bombardment mass spectrometry and 500-MHz 1H NMR analysis as delta 4,5GlcA beta 1-4GlcNAc (6-sulfate)alpha 1-4GlcA beta 1-4GlcN(N,3-disulfate), delta 4,5 GlcA beta 1-4GlcNAc(6-sulfate)alpha 1-4GlcA beta 1-4GlcN (N,3,6-trisulfate), and delta 4,5GlcA beta 1-4GlcN (N,6-disulfate)alpha 1-4GlcA beta 1-4GlcN(N,3,6-trisulfate). The three components share the 3-O-sulfated reducing GlcN and the 6-O-sulfated internal GlcN, indicating that they are structural variants derived from the nonreducing portion of the minimal pentasaccharide sequence required for binding to antithrombin III. Isolation of the pentasulfated component has never been reported. Their unexpected resistance to heparitinases I and II indicates that 3-O-sulfation of the reducing GlcN contributes to the resistant nature of these Tetrasaccharides to the enzymes. The present study demonstrates that the nonreducing trisaccharide portion of the structural variants of the antithrombin III-binding pentasaccharide sequence can be isolated in Tetrasaccharides resistant to heparinase/heparitinases I and II, while the rest of the repeating region is degraded into disaccharide units. The lyase treatment is applicable to evaluation of heparin/heparan sulfate preparations in terms of the presence or absence of the specific structure containing the 3-O-sulfated GlcN representing biosynthetic precursors, intermediates or final products of the binding site.
Richard R. Schmidt - One of the best experts on this subject based on the ideXlab platform.
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complex structures of antennary human milk oligosaccharides synthesis of a branched octasaccharide
European Journal of Organic Chemistry, 2001Co-Authors: Petra Knuhr, Matthias Grathwohl, Julio C Castropalomino, Richard R. SchmidtAbstract:We have developed a highly convergent synthetic route for the synthesis of the branched structure of human milk octasaccharide β-D-galactopyranosyl-(13)-2-acetamido-2-de oxy-β-D-glucopyranosyl-(13)-β-D-galactopyranosyl)-(14)-2-acetamido-2-deoxy-β-D-glucopyranosyl-(16)-[β-D-galactopyranosyl-(13)-2-acetamido-2-deoxy-β-D-glucopyranosyl-(13)]-β-D-galactopyranosyl-(14)-α,β-Dglucopyranose (1). In the retrosynthetic analysis, target structure 1 was disconnected into building blocks 2−6. Starting from only four known building blocks − 4, 7, 8, and 12 − the required three disaccharide units were obtained, resulting after further protecting group manipulation and glycoside bond formation in the desired Tetrasaccharides 13 and 16. Cleavage of the TBDMS group of 13 afforded tetrasaccharide 14, which was transformed into isolactosamine-β-(13)-lactosamine trichloroacetimidate 15. Removal of the 4b,6b-O-benzylidene group of tetrasaccharide 16 gave the lacto-N-tetraose acceptor 17, to afford the protected octasaccharide 18 on glycosylation with donor 15. Complete deprotection of the octasaccharide by way of 19 afforded target human milk oligosaccharide 1 in a short and efficient route.
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Complex Structures of Antennary Human Milk Oligosaccharides − Synthesis of a Branched Octasaccharide
European Journal of Organic Chemistry, 2001Co-Authors: Petra Knuhr, Julio C. Castro-palomino, Matthias Grathwohl, Richard R. SchmidtAbstract:We have developed a highly convergent synthetic route for the synthesis of the branched structure of human milk octasaccharide β-D-galactopyranosyl-(13)-2-acetamido-2-de oxy-β-D-glucopyranosyl-(13)-β-D-galactopyranosyl)-(14)-2-acetamido-2-deoxy-β-D-glucopyranosyl-(16)-[β-D-galactopyranosyl-(13)-2-acetamido-2-deoxy-β-D-glucopyranosyl-(13)]-β-D-galactopyranosyl-(14)-α,β-Dglucopyranose (1). In the retrosynthetic analysis, target structure 1 was disconnected into building blocks 2−6. Starting from only four known building blocks − 4, 7, 8, and 12 − the required three disaccharide units were obtained, resulting after further protecting group manipulation and glycoside bond formation in the desired Tetrasaccharides 13 and 16. Cleavage of the TBDMS group of 13 afforded tetrasaccharide 14, which was transformed into isolactosamine-β-(13)-lactosamine trichloroacetimidate 15. Removal of the 4b,6b-O-benzylidene group of tetrasaccharide 16 gave the lacto-N-tetraose acceptor 17, to afford the protected octasaccharide 18 on glycosylation with donor 15. Complete deprotection of the octasaccharide by way of 19 afforded target human milk oligosaccharide 1 in a short and efficient route.
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structural motifs of the dimeric lewis glycolipids as determined by nmr spectroscopy and molecular dynamics simulations
Chemistry: A European Journal, 1996Co-Authors: Armin Geyer, Gerd Hummel, Thomas Eisele, Stefan Reinhardt, Richard R. SchmidtAbstract:Several monomeric and dimeric Lewis glycolipids have been investigated by NMR spectroscopy, and structural aspects were modelled by computer. From the pseudo-C2-symmetric tetrasaccharide unit that forms the recognition domain of the Lewis Y and Lewis b antigens, a totally C2-symmetric tetrasaccharide was designed that contains the structural element common to all Lewis antigens. Finally, a model for the presentation of dimeric Lewis antigens at membrane surfaces was derived. The overall shapes of the dimeric Lewis oligosaccharides are defined by the connectivity of the sugar residues within rigid tri- and tetrasaccharide building blocks.
Goutam Guchhait - One of the best experts on this subject based on the ideXlab platform.
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Convergent synthesis of the tetrasaccharide repeating unit corresponding to the O-antigen of the verotoxin-producing Escherichia coli O176
Glycoconjugate Journal, 2011Co-Authors: Goutam Guchhait, Anup Kumar MisraAbstract:A convergent synthesis of the tetrasaccharide repeating unit of the O -antigen of the verotoxin producing E. coli O176 has been achieved in excellent yield adopting a [2 + 2] block glycosylation strategy. The β-D-mannosidic moiety of the tetrasaccharide was prepared from β-D-glucoside and α-D-galactosamine moiety was derived from D-galactal. The tetrasaccharide was synthesized as its 2-trimethylsilylethyl glycoside in excellent yield. All intermediate steps are high yielding. Figure A convergent synthetic strategy of the tetrasaccharide repeating unit corresponding to the O -antigen of verotoxin-producing Escherichia coli has been successfully developed using stereoselective [2 + 2] block glycosylation technique.
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Convergent synthesis of the tetrasaccharide repeating unit corresponding to the O-antigen of the verotoxin-producing Escherichia coli O176
Glycoconjugate Journal, 2011Co-Authors: Goutam Guchhait, Anup Kumar MisraAbstract:A convergent synthesis of the tetrasaccharide repeating unit of the O -antigen of the verotoxin producing E. coli O176 has been achieved in excellent yield adopting a [2 + 2] block glycosylation strategy. The β-D-mannosidic moiety of the tetrasaccharide was prepared from β-D-glucoside and α-D-galactosamine moiety was derived from D-galactal. The tetrasaccharide was synthesized as its 2-trimethylsilylethyl glycoside in excellent yield. All intermediate steps are high yielding. Figure A convergent synthetic strategy of the tetrasaccharide repeating unit corresponding to the O -antigen of verotoxin-producing Escherichia coli has been successfully developed using stereoselective [2 + 2] block glycosylation technique.
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Convergent synthesis of the tetrasaccharide repeating unit corresponding to the O-antigen of the verotoxin-producing Escherichia coli O176.
Glycoconjugate Journal, 2011Co-Authors: Goutam Guchhait, Anup Kumar MisraAbstract:A convergent synthesis of the tetrasaccharide repeating unit of the O-antigen of the verotoxin producing E. coli O176 has been achieved in excellent yield adopting a [2 + 2] block glycosylation strategy. The β-D-mannosidic moiety of the tetrasaccharide was prepared from β-D-glucoside and α-D-galactosamine moiety was derived from D-galactal. The tetrasaccharide was synthesized as its 2-trimethylsilylethyl glycoside in excellent yield. All intermediate steps are high yielding.
