酶架构:通过基质诱导的形状变化来构建活性奥罗提丁5'-单酸脱酶
Archie C Reyes1, Tina L Amyes1, John P Richard1
1Department of Chemistry, University at Buffalo, SUNY , Buffalo, New York 14260-3000, United States.
Journal of the American Chemical Society
|October 24, 2017
概括
通过基质诱导的形状变化稳定过渡状态. 这种涉及基质碎片的酶机制可能导致酶激活.
科学领域:
- 生物化学
- 酶动力学
- 结构生物学
背景情况:
- 奥罗提丁5 extquotesingle-monophosphate脱碳酶 (OMPDC) 是胺生物合成中的一个关键酶.
- 了解酶机制,特别是过渡状态稳定,对于药物开发至关重要.
研究的目的:
- 研究OMPDC的催化机制,重点是过渡状态稳定.
- 阐明基质结合和酶形状变化的作用.
主要方法:
- 使用OMPDC及其基质5-酸盐 (FO) 的酶动力学研究.
- 动力参数 (kcat/Km) 和过渡状态稳定能量的分析.
- 研究了基质碎片 (基,基,酸盐环) 和效应剂 (酸,d-甘3-酸盐,d-红4-酸盐) 的稳定作用.
主要成果:
- OMPDC将OMP脱碳的过渡状态稳定为31kcal/mol.
- 对二 (11.8 kcal/mol),基环 (10.6 kcal/mol) 和酸环 (8.6 kcal/mol) 的具体稳定性贡献量化.
- 用酸二,d-甘3-和d-酸稳定了FO脱碳的过渡状态,分别为5.2,7.2和9.0千卡/mol.
- 基质片段的结合驱动了酶的结构变化,形成了一个子复合体.
结论:
- OMPDC利用基质诱导的形状变化进行催化,稳定过渡状态.
- 基质碎片的结合相互作用对于锁定酸环在具有催化能力的形状至关重要.
- 酶激活可能是基质诱导的形状变化的结果.
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