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Ian Cumpstey - One of the best experts on this subject based on the ideXlab platform.
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β-Mannosidase and β-hexosaminidase inhibitors: synthesis of 1,2-bis-epi-valienamine and 1-epi-2-acetamido-2-deoxy-valienamine from d-mannose
2009Co-Authors: Clinton Ramstadius, Henrik Stalbrand, Omid Hekmat, Lars Eriksson, Ian CumpsteyAbstract:A partially protected C-5=C-5a unsaturated carbasugar with alpha-lyxo configuration is synthesised in five steps and 26% overall yield from a known mannose-derived hemiacetal, using ring-closing metathesis as a key step. This carbasugar is converted into valienamine derivatives with beta-lyxo (i.e., corresponding to beta-manno at C-1-C-4), alpha-lyxo (i.e., corresponding to alpha-manno at C-1-C-4) and beta-2-acetamido-2-deoxy-xylo (i.e., corresponding to beta-GlcNAc at C-1-C-4) configurations. This is the first report of the synthesis of the beta-lyxo compound, 1,2-bis-epi-valienamine, which was found to inhibit Cellulomonas fimi Beta-Mannosidase (CfMan2A) with K-i 140 mu M. We report the crystal structures of three protected C-5=C-5a unsaturated carbasugars with lyxo configuration. (C) 2009 Elsevier Ltd. All rights reserved
Henrik Stalbrand - One of the best experts on this subject based on the ideXlab platform.
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β-Mannosidase and β-hexosaminidase inhibitors: synthesis of 1,2-bis-epi-valienamine and 1-epi-2-acetamido-2-deoxy-valienamine from d-mannose
2009Co-Authors: Clinton Ramstadius, Henrik Stalbrand, Omid Hekmat, Lars Eriksson, Ian CumpsteyAbstract:A partially protected C-5=C-5a unsaturated carbasugar with alpha-lyxo configuration is synthesised in five steps and 26% overall yield from a known mannose-derived hemiacetal, using ring-closing metathesis as a key step. This carbasugar is converted into valienamine derivatives with beta-lyxo (i.e., corresponding to beta-manno at C-1-C-4), alpha-lyxo (i.e., corresponding to alpha-manno at C-1-C-4) and beta-2-acetamido-2-deoxy-xylo (i.e., corresponding to beta-GlcNAc at C-1-C-4) configurations. This is the first report of the synthesis of the beta-lyxo compound, 1,2-bis-epi-valienamine, which was found to inhibit Cellulomonas fimi Beta-Mannosidase (CfMan2A) with K-i 140 mu M. We report the crystal structures of three protected C-5=C-5a unsaturated carbasugars with lyxo configuration. (C) 2009 Elsevier Ltd. All rights reserved
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cloning and characterisation of aspergillus niger genes encoding an alpha galactosidase and a beta mannosidase involved in galactomannan degradation
2001Co-Authors: Pia Ademark, Henrik Stalbrand, Per Hägglund, R P De Vries, Jaap VisseAbstract:Alpha-galactosidase (EC 3.2.1.22) and Beta-Mannosidase (EC 3.2.1.25) participate in the hydrolysis of complex plant saccharides such as galacto(gluco)mannans. Here we report on the cloning and characterization of genes encoding an alpha-galactosidase (AglC) and a Beta-Mannosidase (MndA) from Aspergillus niger. The aglC and mndA genes code for 747 and 931 amino acids, respectively, including the eukaryotic signal sequences. The predicted isoelectric points of AglC and MndA are 4.56 and 5.17, and the calculated molecular masses are 79.674 and 102.335 kDa, respectively. Both AglC and MndA contain several putative N-glycosylation sites. AglC was assigned to family 36 of the glycosyl hydrolases and MndA was assigned to family 2. The expression patterns of aglC and mndA and two other genes encoding A. niger alpha-galactosidases (aglA and aglB) during cultivation on galactomannan were studied by Northern analysis. A comparison of gene expression on monosaccharides in the A. niger wild-type and a CreA mutant strain showed that the carbon catabolite repressor protein CreA has a strong influence on aglA, but not on aglB, aglC or mndA. AglC and MndA were purified from constructed overexpression strains of A. niger, and the combined action of these enzymes degraded a galactomanno-oligosaccharide into galactose and mannose. The possible roles of AglC and MndA in galactomannan hydrolysis is discussed.
Clinton Ramstadius - One of the best experts on this subject based on the ideXlab platform.
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β-Mannosidase and β-hexosaminidase inhibitors: synthesis of 1,2-bis-epi-valienamine and 1-epi-2-acetamido-2-deoxy-valienamine from d-mannose
2009Co-Authors: Clinton Ramstadius, Henrik Stalbrand, Omid Hekmat, Lars Eriksson, Ian CumpsteyAbstract:A partially protected C-5=C-5a unsaturated carbasugar with alpha-lyxo configuration is synthesised in five steps and 26% overall yield from a known mannose-derived hemiacetal, using ring-closing metathesis as a key step. This carbasugar is converted into valienamine derivatives with beta-lyxo (i.e., corresponding to beta-manno at C-1-C-4), alpha-lyxo (i.e., corresponding to alpha-manno at C-1-C-4) and beta-2-acetamido-2-deoxy-xylo (i.e., corresponding to beta-GlcNAc at C-1-C-4) configurations. This is the first report of the synthesis of the beta-lyxo compound, 1,2-bis-epi-valienamine, which was found to inhibit Cellulomonas fimi Beta-Mannosidase (CfMan2A) with K-i 140 mu M. We report the crystal structures of three protected C-5=C-5a unsaturated carbasugars with lyxo configuration. (C) 2009 Elsevier Ltd. All rights reserved
Omid Hekmat - One of the best experts on this subject based on the ideXlab platform.
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β-Mannosidase and β-hexosaminidase inhibitors: synthesis of 1,2-bis-epi-valienamine and 1-epi-2-acetamido-2-deoxy-valienamine from d-mannose
2009Co-Authors: Clinton Ramstadius, Henrik Stalbrand, Omid Hekmat, Lars Eriksson, Ian CumpsteyAbstract:A partially protected C-5=C-5a unsaturated carbasugar with alpha-lyxo configuration is synthesised in five steps and 26% overall yield from a known mannose-derived hemiacetal, using ring-closing metathesis as a key step. This carbasugar is converted into valienamine derivatives with beta-lyxo (i.e., corresponding to beta-manno at C-1-C-4), alpha-lyxo (i.e., corresponding to alpha-manno at C-1-C-4) and beta-2-acetamido-2-deoxy-xylo (i.e., corresponding to beta-GlcNAc at C-1-C-4) configurations. This is the first report of the synthesis of the beta-lyxo compound, 1,2-bis-epi-valienamine, which was found to inhibit Cellulomonas fimi Beta-Mannosidase (CfMan2A) with K-i 140 mu M. We report the crystal structures of three protected C-5=C-5a unsaturated carbasugars with lyxo configuration. (C) 2009 Elsevier Ltd. All rights reserved
Lars Eriksson - One of the best experts on this subject based on the ideXlab platform.
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β-Mannosidase and β-hexosaminidase inhibitors: synthesis of 1,2-bis-epi-valienamine and 1-epi-2-acetamido-2-deoxy-valienamine from d-mannose
2009Co-Authors: Clinton Ramstadius, Henrik Stalbrand, Omid Hekmat, Lars Eriksson, Ian CumpsteyAbstract:A partially protected C-5=C-5a unsaturated carbasugar with alpha-lyxo configuration is synthesised in five steps and 26% overall yield from a known mannose-derived hemiacetal, using ring-closing metathesis as a key step. This carbasugar is converted into valienamine derivatives with beta-lyxo (i.e., corresponding to beta-manno at C-1-C-4), alpha-lyxo (i.e., corresponding to alpha-manno at C-1-C-4) and beta-2-acetamido-2-deoxy-xylo (i.e., corresponding to beta-GlcNAc at C-1-C-4) configurations. This is the first report of the synthesis of the beta-lyxo compound, 1,2-bis-epi-valienamine, which was found to inhibit Cellulomonas fimi Beta-Mannosidase (CfMan2A) with K-i 140 mu M. We report the crystal structures of three protected C-5=C-5a unsaturated carbasugars with lyxo configuration. (C) 2009 Elsevier Ltd. All rights reserved