D-tagaturonate

• 分子结构分类: 有机化合物 - 有机酸及其衍生物 - 羟基酸及其衍生物
• 英文名称: D-tagaturonate
• 英文别名: (2S,3R,4S)-2,3,4,6-tetrahydroxy-5-oxohexanoate
• 化学式: C6H9O7-
• 分子量: 193.13
• InChiKey: IZSRJDGCGRAUAR-WDCZJNDASA-M

计算性质

• 辛醇/水分配系数(LogP)：
  -2.3
• 重原子数：
  13
• 可旋转键数：
  4
• 环数：
  0.0
• sp3杂化的碳原子比例：
  0.67
• 拓扑面积：
  138
• 氢给体数：
  4
• 氢受体数：
  7

反应信息

• 作为反应物：
  描述：

  D-tagaturonate 生成 keto-D-fructuronate
  参考文献：
  名称：

  Tagaturonate-fructuronate epimerase UxaE, a novel enzyme in the hexuronate catabolic network inThermotoga maritima

  摘要：

  SummaryThermotoga maritima is a marine hyperthermophilic microorganism that degrades a wide range of simple and complex carbohydrates including pectin and produces fermentative hydrogen at high yield. Galacturonate and glucuronate, two abundant hexuronic acids in pectin and xylan, respectively, are catabolized via committed metabolic pathways to supply carbon and energy for a variety of microorganisms. By a combination of bioinformatics and experimental techniques we identified a novel enzyme family (named UxaE) catalysing a previously unknown reaction in the hexuronic acid catabolic pathway, epimerization of tagaturonate to fructuronate. The enzymatic activity of the purified recombinant tagaturonate epimerase from T. maritima was directly confirmed and kinetically characterized. Its function was also confirmed by genetic complementation of the growth of the Escherichia coli uxaB knockout mutant strain on galacturonate. An inferred novel galacturonate to mannonate catabolic pathway in T. maritima was reconstituted in vitro using a mixture of recombinant purified enzymes UxaE, UxaC and UxuB. Members of the newly identified UxaE family were identified in ∼ 50 phylogenetically diverse heterotrophic bacteria from aquatic and soil environments. The genomic context of respective genes and reconstruction of associated pathways suggest that UxaE enzymatic and biological function remains conserved in all of these species.

  DOI：

  10.1111/j.1462-2920.2012.02856.x
• 作为产物：
  描述：

  5-dehydro-L-gluconate 生成 D-tagaturonate
  参考文献：
  名称：

  滨海嗜热菌中的新型肌醇分解代谢途径。

  摘要：

  肌醇（MI）是各种代谢物的关键糖醇成分，例如动植物细胞中富含的磷脂酰肌醇基磷脂。MI降解的七步途径先前已在包括枯草芽孢杆菌在内的各种土壤细菌中表征。通过生物信息学和实验技术的结合，我们在海洋嗜热菌Maritomata maritima中鉴定了MI分解代谢途径的新变体。通过使用纯化的重组蛋白进行体外生化分析，我们鉴定了TM0412-TM0416染色体基因簇中编码的四种肌醇分解代谢酶。海藻弧菌中的新型分解代谢途径以使用肌醇脱氢酶IolG的常规途径开始，随后发生了三个新的反应。第一个2-酮-肌醇中间体被另一个以前未知的NAD依赖性脱氢酶TM0412（命名为IolM）氧化，该反应的一个尚未鉴定的产物进一步被TM0413（IolN）水解形成5-酮-1 -葡萄糖酸盐。第四步骤涉及通过TM0416（Iol10）将5-酮-1-葡萄糖酸酯差向异构化为d-塔格龙酸酯。maritima不能作为单一碳源在肌醇上生

  DOI：

  10.1111/1462-2920.12096

文献信息

• Construction of hybrid plasmids containing the Escherichia coli uxaB gene: analysis of its regulation and direction of transcription
  作者：C Blanco、M Mata-Gilsinger、P Ritzenthaler

  DOI：10.1128/jb.153.2.747-755.1983

  日期：1983.2

  The uxaB gene of Escherichia coli, encoding for altronate oxidoreductase involved in the hexuronate degradative pathway, was isolated on a ColE1-uxaB hybrid plasmid from the Clarke and Carbon bank. The restriction map of this plasmid was established. The uxaB gene was mapped on a 1.5-megadalton HindIII-KpnI DNA fragment. Use of an in vitro gene fusion between uxaB and lacZ genes led to the determination that uxaB is transcribed from the KpnI towards the HindIII restriction sites. Gene amplification in cells containing various uxaB hybrid plasmids allowed us to show a gradation in the level of repression of exu operator sites by the exuR regulatory gene product.

  大肠杆菌uxaB基因编码的altronate氧化还原酶参与了六糖酸降解途径，该基因从Clarke和Carbon库的ColE1-uxaB杂交质粒中分离出来。建立了该质粒的限制图谱。uxaB基因位于1.5兆碱基对的HindIII-KpnI DNA片段上。uxaB与lacZ基因的体外基因融合实验表明，uxaB从KpnI向HindIII限制位点转录。在含有不同uxaB杂交质粒的细胞中进行基因扩增，我们可以展示exuR调节基因产物对exu操作员位点的抑制水平的渐进变化。
• The yjjN of E. coli codes for an l-galactonate dehydrogenase and can be used for quantification of l-galactonate and l-gulonate
  作者：Joosu Kuivanen、Peter Richard

  DOI：10.1007/s12010-014-0969-0

  日期：2014.8

  Escherichia coli is able to utilize l-galactonate as a sole carbon source. A metabolic pathway for l-galactonate catabolism is described in E. coli, and it is known to be interconnected with d-galacturonate metabolism. The corresponding gene encoding the first enzyme in the l-galactonate pathway, l-galactonate-5-dehydrogenase, was suggested to be yjjN. However, l-galactonate dehydrogenase activity was never demonstrated with the yjjN gene product. Here, we show that YjjN is indeed an l-galactonate dehydrogenase having activity also for l-gulonate. The K m and k cat for l-galactonate were 19.5 ± 0.6 mM and 0.51 ± 0.03 s−1, respectively. In addition, YjjN was applied for a quantitative detection of the both of these substances in a coupled assay. The detection limits for l-galactonate and l-gulonate were 1.65 and 10 μM, respectively.

  大肠杆菌能够利用l-半乳糖酸作为唯一的碳源。大肠杆菌中l-半乳糖酸分解代谢的代谢途径已经得到描述，并且已知它与d-半乳糖酸代谢相互关联。l-半乳糖酸途径中第一酶的相应编码基因l-半乳糖酸-5-脱氢酶被认为是yjjN。然而，从未证实过yjjN基因产物具有l-半乳糖酸脱氢酶活性。在这里，我们证明YjjN确实是一种l-半乳糖酸脱氢酶，对l-古洛糖酸也具有活性。l-半乳糖酸的K m和k cat分别为19.5 ± 0.6 mM和0.51 ± 0.03 s−1。此外，YjjN还用于定量检测耦合分析中的这两种物质。l-半乳糖酸和l-古洛糖酸的检测限分别为1.65和10 μM。
• <scp>l</scp>-Galactose Metabolism in <i>Bacteroides vulgatus</i> from the Human Gut Microbiota
  作者：Merlin Eric Hobbs、Howard J. Williams、Brandan Hillerich、Steven C. Almo、Frank M. Raushel

  DOI：10.1021/bi500656m

  日期：2014.7.22

  A previously unknown metabolic pathway for the utilization of L-galactose was discovered in a prevalent gut bacterium, Bacteroides vulgatus. The new pathway consists of three previously uncharacterized enzymes that were found to be responsible for the conversion of L-galactose to D-tagaturonate. Bvu0219 (L-galactose dehydrogenase) was determined to oxidize L-galactose to L-galactono-1,5-lactone with k(cat) and k(cat)/K-m values of 21 s(-1) and 2.0 x 10(5) M-1 s(-1), respectively. The kinetic product of Bvu0219 is rapidly converted nonenzymatically to the thermodynamically more stable L-galactono-1,4-lactone. Bvu0220 (L-galactono-1,S-lactonase) hydrolyzes both the kinetic and thermodynamic products of Bvu0219 to L-galactonate. However, L-galactono-1,5-lactone is estimated to be hydrolyzed 300-fold faster than its thermodynamically more stable counterpart, L-galactono-1,4-lactone. In the final step of this pathway, Bvu0222 (L-galactonate dehydrogenase) oxidizes L-galactonate to D-tagaturonate with k(cat) and k(cat) /K-m values of 0.6 s(-1) and 1.7 x 10(4) M-1 s(-1), respectively. In the reverse direction, D-tagaturonate is reduced to L-galactonate with values of k(cat) and k(cat)/K-m of 90 s(-1) and 1.6 X 10(5) M-1 s(-1), respectively. D-Tagaturonate is subsequently converted to D-glyceraldehyde and pyruvate through enzymes encoded within the degradation pathway for D-glucuronate and D-galacturonate.
• KILGORE W.W.; STARR M.P., J Biol Chem, 1959, 0021-9258, 2227-35
  作者：KILGORE W.W.、STARR M.P.

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