UDP-α-D-4-ketoxylose | 25747-29-9

• 分子结构分类: 有机化合物 - 核苷、核苷酸和类似物 - 嘧啶核苷酸
• 英文名称: UDP-α-D-4-ketoxylose
• 英文别名: UX4O；UDP-β-L-threo-pentopyranosyl-4''-ulose；UDP-4-keto-pentose；UDP-L-Ara4O；[(2R,3R,4R)-3,4-dihydroxy-5-oxooxan-2-yl] [[(2R,3S,4R,5R)-5-(2,4-dioxopyrimidin-1-yl)-3,4-dihydroxyoxolan-2-yl]methoxy-hydroxyphosphoryl] hydrogen phosphate
• CAS: 25747-29-9
• 化学式: C₁₄H₂₀N₂O₁₆P₂
• 分子量: 534.264
• InChiKey: URJZIQLTPCJVMW-QNSCKLTRSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  -6.1
• 重原子数：
  34
• 可旋转键数：
  8
• 环数：
  3.0
• sp3杂化的碳原子比例：
  0.64
• 拓扑面积：
  268
• 氢给体数：
  7
• 氢受体数：
  16

反应信息

• 作为反应物：
  描述：

  UDP-α-D-4-ketoxylose 在 Ralstonia solanacearum strain GMI₁₀₀₀ UDP-4-keto-pentose/UDP-xylose synthase; molecular mass determined by size-exclusion chromatography SDS-PAGE: 41kDa 、 还原型辅酶Ⅰ 作用下， 反应 0.33h， 生成 [5-(2,4-二氧代嘧啶-1-基)-3,4-二羟基四氢呋喃-2-基]甲基[羟基-(3,4,5-三羟基四氢吡喃-2-基)氧基磷酰]磷酸氢酯
  参考文献：
  名称：

  Identification of a Bifunctional UDP-4-keto-pentose/UDP-xylose Synthase in the Plant Pathogenic Bacterium Ralstonia solanacearum Strain GMI1000, a Distinct Member of the 4,6-Dehydratase and Decarboxylase Family

  摘要：

  The UDP-sugar interconverting enzymes involved in UDPGlcA metabolism are well described in eukaryotes but less is known in prokaryotes. Here we identify and characterize a gene (RsU4kpxs) from Ralstonia solanacearum str. GMI1000, which encodes a dual function enzyme not previously described. One activity is to decarboxylate UDP-glucuronic acid to UDP-beta-L-threo-pentopyranosyl-4 ''-ulose in the presence of NAD(+). The second activity converts UDP-beta-L-threo-pentopyranosyl-4 ''-ulose and NADH to UDP-xylose and NAD(+), albeit at a lower rate. Our data also suggest that following decarboxylation, there is stereospecific protonation at the C5 pro-R position. The identification of the R. solanacearum enzyme enables us to propose that the ancestral enzyme of UDP-xylose synthase and UDP-apiose/UDP-xylose synthase was diverged to two distinct enzymatic activities in early bacteria. This separation gave rise to the current UDP-xylose synthase in animal, fungus, and plant as well as to the plant Uaxs and bacterial ArnA and U4kpxs homologs.

  DOI：

  10.1074/jbc.m109.066803
• 作为产物：
  描述：

  6-[[[5-(2,4-二氧代嘧啶-1-基)-3,4-二羟基四氢呋喃-2-基]甲氧基-羟基磷酰]氧基-羟基磷酰]氧基-3,4,5-三羟基四氢吡喃-2-羧酸 在 Ralstonia solanacearum strain GMI₁₀₀₀ UDP-4-keto-pentose/UDP-xylose synthase; molecular mass determined by size-exclusion chromatography SDS-PAGE: 41kDa 、 nicotinamide adenine dinucleotide 作用下， 反应 0.33h， 生成 UDP-α-D-4-ketoxylose
  参考文献：
  名称：

  Identification of a Bifunctional UDP-4-keto-pentose/UDP-xylose Synthase in the Plant Pathogenic Bacterium Ralstonia solanacearum Strain GMI1000, a Distinct Member of the 4,6-Dehydratase and Decarboxylase Family

  摘要：

  The UDP-sugar interconverting enzymes involved in UDPGlcA metabolism are well described in eukaryotes but less is known in prokaryotes. Here we identify and characterize a gene (RsU4kpxs) from Ralstonia solanacearum str. GMI1000, which encodes a dual function enzyme not previously described. One activity is to decarboxylate UDP-glucuronic acid to UDP-beta-L-threo-pentopyranosyl-4 ''-ulose in the presence of NAD(+). The second activity converts UDP-beta-L-threo-pentopyranosyl-4 ''-ulose and NADH to UDP-xylose and NAD(+), albeit at a lower rate. Our data also suggest that following decarboxylation, there is stereospecific protonation at the C5 pro-R position. The identification of the R. solanacearum enzyme enables us to propose that the ancestral enzyme of UDP-xylose synthase and UDP-apiose/UDP-xylose synthase was diverged to two distinct enzymatic activities in early bacteria. This separation gave rise to the current UDP-xylose synthase in animal, fungus, and plant as well as to the plant Uaxs and bacterial ArnA and U4kpxs homologs.

  DOI：

  10.1074/jbc.m109.066803

文献信息

• Human UDP-α-<scp>d</scp>-xylose Synthase and <i>Escherichia coli</i> ArnA Conserve a Conformational Shunt That Controls Whether Xylose or 4-Keto-Xylose Is Produced
  作者：Samuel J. Polizzi、Richard M. Walsh、William B. Peeples、Jae-Min Lim、Lance Wells、Zachary A. Wood

  DOI：10.1021/bi301135b

  日期：2012.11.6

  Human UDP-alpha-D-xylose synthase (hUXS) is a member of the short-chain dehydrogenase/reductase family of nucleotide-sugar modifying enzymes. hUXS contains a bound NAD(+) cofactor that it recycles by first oxidizing UDP-alpha-D-glucuronic acid (UGA), and then reducing the UDP-alpha-D-4-keto-xylose (UX4O) to produce UDP-alpha-D-xylose (UDX). Despite the observation that purified hUXS contains a bound cofactor, it has been reported that exogenous NAD+ will stimulate enzyme activity. Here we show that a small fraction of hUXS releases the NADH and UX4O intermediates as products during turnover. The resulting apoenzyme can be rescued by exogenous NAD(+), explaining the apparent stimulatory effect of added cofactor. The slow release of NADH and UX4O as side products by hUXS is reminiscent of the Escherichia coli UGA decarboxylase (ArnA), a related enzyme that produces NADH and UX4O as products. We report that ArnA can rebind NADH and UX4O to slowly make UDX. This means that both enzymes share the same catalytic machinery, but differ in the preferred final product. We present a bifurcated rate equation that explains how the substrate is shunted to the distinct final products. Using a new crystal structure of hUXS, we identify the structural elements of the shunt and propose that the local unfolding of the active site directs reactants toward the preferred products. Finally, we present evidence that the release of NADH and UX4O involves a cooperative conformational change that is conserved in both enzymes.
• Identification of a Bifunctional UDP-4-keto-pentose/UDP-xylose Synthase in the Plant Pathogenic Bacterium Ralstonia solanacearum Strain GMI1000, a Distinct Member of the 4,6-Dehydratase and Decarboxylase Family
  作者：Xiaogang Gu、John Glushka、Yanbin Yin、Ying Xu、Timothy Denny、James Smith、Yingnan Jiang、Maor Bar-Peled

  DOI：10.1074/jbc.m109.066803

  日期：2010.3

  The UDP-sugar interconverting enzymes involved in UDPGlcA metabolism are well described in eukaryotes but less is known in prokaryotes. Here we identify and characterize a gene (RsU4kpxs) from Ralstonia solanacearum str. GMI1000, which encodes a dual function enzyme not previously described. One activity is to decarboxylate UDP-glucuronic acid to UDP-beta-L-threo-pentopyranosyl-4 ''-ulose in the presence of NAD(+). The second activity converts UDP-beta-L-threo-pentopyranosyl-4 ''-ulose and NADH to UDP-xylose and NAD(+), albeit at a lower rate. Our data also suggest that following decarboxylation, there is stereospecific protonation at the C5 pro-R position. The identification of the R. solanacearum enzyme enables us to propose that the ancestral enzyme of UDP-xylose synthase and UDP-apiose/UDP-xylose synthase was diverged to two distinct enzymatic activities in early bacteria. This separation gave rise to the current UDP-xylose synthase in animal, fungus, and plant as well as to the plant Uaxs and bacterial ArnA and U4kpxs homologs.