trans-3-chloroacrylate | 237747-38-5

• 分子结构分类: 有机化合物 - 有机酸及其衍生物 - 羧酸及其衍生物
• 英文名称: trans-3-chloroacrylate
• 英文别名: 3-Chloroacrylate；(E)-3-chloroprop-2-enoate
• CAS: 237747-38-5
• 化学式: C₃H₂ClO₂
• 分子量: 105.501
• InChiKey: MHMUCYJKZUZMNJ-OWOJBTEDSA-M

计算性质

• 辛醇/水分配系数(LogP)：
  1.3
• 重原子数：
  6
• 可旋转键数：
  0
• 环数：
  0.0
• sp3杂化的碳原子比例：
  0.0
• 拓扑面积：
  40.1
• 氢给体数：
  0
• 氢受体数：
  2

反应信息

• 作为反应物：
  描述：

  trans-3-chloroacrylate 在 cis-3-chloroacrylic acid dehalogenase homologue from Mycobacterium smegmatis strain MC₂ 155 作用下， 生成 malonate semialdehyde
  参考文献：
  名称：

  Characterization of a Newly Identified Mycobacterial Tautomerase with Promiscuous Dehalogenase and Hydratase Activities Reveals a Functional Link to a Recently Diverged cis-3-Chloroacrylic Acid Dehalogenase

  摘要：

  The enzyme cis-3-chloroacrylic acid dehalogenase (cis-CaaD) is found in a bacterial pathway that degrades a synthetic nematocide, cis-1,3-dichloropropene, introduced in the 20th century. The previously determined crystal structure of cis-CaaD and its promiscuous phenylpyruvate tautomerase (PPT) activity link this dehalogenase to the tautomerase superfamily, a group of homologous proteins that are characterized by a catalytic amino-terminal proline and a beta-alpha-beta structural fold. The low-level PPT activity of cis-CaaD, which may be a vestige of the function of its progenitor, prompted us to search the databases for a homologue of cis-CaaD that was annotated as a putative tautomerase and test both its PPT and cis-CaaD activity. We identified a mycobacterial cis-CaaD homologue (designated MsCCH2) that shares key sequence and active site features with cis-CaaD. Kinetic and H-1 NMR spectroscopic studies show that MsCCH2 functions as an efficient PPT and exhibits low-level promiscuous dehalogenase activity, processing both cis- and trans-3-chloroacrylic acid. To further probe the active site of MsCCH2, the enzyme was incubated with 2-oxo-3-pentynoate (2-OP). At pH 8.5, MsCCH2 is inactivated by 2-OP due to the covalent modification of Pro-1, suggesting that Pro-1 functions as a nucleophile at pH 8.5 and attacks 2-OP in a Michael-type reaction. At pH 6.5, however, MsCCH2 exhibits hydratase activity and converts 2-013 to acetopyruvate, which implies that Pro-1 is cationic at pH 6.5 and not functioning as a nucleophile. At pH 7.5, the hydratase and inactivation reactions occur simultaneously. From these results, it can be inferred that Pro-1 of MsCCH2 has a pK(a) value that lies in between that of a typical tautomerase (pK(a) of Pro-I similar to 6) and that of cis-CaaD (pK(a) of Pro-I similar to 9). The shared activities and structural features, coupled with the intermediate pK(a) of Pro-1, suggest that MsCCH2 could be characteristic of an evolutionary intermediate along the past route for the divergence of cis-CaaD from an unknown superfamily tautomerase. This makes MsCCH2 an ideal candidate for laboratory evolution of its promiscuous dehalogenase activity, which could identify additional features necessary for a fully active cis-CaaD. Such results will provide insight into pathways that could lead to the rapid divergent evolution of an efficient cis-CaaD enzyme.

  DOI：

  10.1021/bi200071k