用35 GHz 2H ENDOR光谱测定甲抑制的桑氧化酶的结构
Muralidharan Shanmugam1, Bo Zhang, Rebecca L McNaughton
1Chemistry Department, Northwestern University, Evanston, Illinois 60208-3113, USA.
Journal of the American Chemical Society
|September 24, 2010
概括
丁氧化酶 (I) 甲抑制涉及一个Mo(V) 活性位点. 新的ENDOR光谱揭示了四个环 adduct,排除了直接的Mo-C键,并澄清了酶结构.
科学领域:
- 生物化学 生物化学
- 酶学 是一种酶学.
- 频谱学是一种光谱学.
背景情况:
- 几十年来,氧化酶 (I) 的甲抑制的氧化状态 (Mo(V)) 是研究的主题.
- 以前的研究表明,在I的活性位点中,基于超细合的基础上,有直接的碳 (Mo-C) 键.
- 这一假设被相关的化氧降解酶酶的晶体结构间接支持.
研究的目的:
- 为了明确确定甲抑制的丁氧化酶 (I) 的活性位结构.
- 为了解决围绕在酶活性部位中提出的Mo-C键的含糊性.
- 为了阐明酸氧化酶中甲抑制的机制.
主要方法:
- 使用质子 ((1) H) 和 ((2) H) 同位素的电子核双共振 (ENDOR) 谱学.
- 在H(2) O/D(2) O缓冲溶液中进行的实验.
- 密度函数理论 (DFT) 计算以支持光谱发现.
主要成果:
- ENDOR光谱明确地揭示了活性位带的四个成员环结构.
- 该结构涉及甲添加物 (CH(2) O) 通过硫 (S) 和氧 (O) 链接与Mo(V) 结合.
- 对于被抑制的酶来说,直接的Mo-C键被明确排除了.
结论:
- 甲抑制的丁氧化酶 (I) 的活性位点具有循环的Mo(V) -CH(2) O附加物,而不是直接的Mo-C键.
- 观察到的大型 (13) C 超精密合是通过跨环状超精密相互作用来解释的.
- 这项研究提供了对甲对丁氧化酶抑制的最终结构理解.
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