酶的FeMo-co活性位点的化学
1School of Chemistry, University of New South Wales, Sydney 2052, Australia.
Journal of the American Chemical Society
|August 4, 2005
概括
酶酶通过一种新的机制催化N(2) 化,其中气进入铁合因子 (FeMo-co) 的S3B位点. 这项研究详细介绍了FeMo-co中的新化学和协调原理,解释了基板化.
科学领域:
- 生物化学和生物有机化学
- 酶的机制 酶的机制
- 亚酶催化剂的催化作用
背景情况:
- 在铁-辅因子 (FeMo-co) 中化的精确化学机制仍然难以捉摸.
- 了解 (H(2)),基质和像CO这样的抑制剂的作用对于阐明催化途径至关重要.
- 在FeMo-co上原子和H(2) 的积累和协调是酶机制的基础.
研究的目的:
- 为了阐明FeMo-co活性位点内的初始 (H) 进入点和随后的协调化学.
- 描述FeMo-co领域的H和H (2) 协调的各种可能性.
- 提出H(2) 生产,运动和基质化的详细机制,包括HD反应.
主要方法:
- 在FeMo-co和相关氨基酸残留的综合化学模型上使用了经过验证的密度函数计算.
- 在FeMo-co活性部位上对H原子和H2的80多种不同的协调可能性进行了表征.
- 计算了H原子和H(2) 运动,生成,结合和解离的反应概况.
主要成果:
- 提出了一种新的H进入机制,通过一个以FeMo-co.的S3B原子终结的水链.
- 确定了前所未有的协调结构,包括八面体Fe{S}{3}{H}{2}{2}{3}{H}).
- 已确立的FeMo-co化学的一般原则:S结合的H的立体化学流动性,差异化的Fe协调部位和协调性.
结论:
- S3B被确定为主要的H入口点,并提出了一个H ((+) 穿机制.
- 这项研究为Mo的存在和FeMo-co.的末端分化提供了机制性的理由.
- 提出了一种化中间体的共识模型,与最近的实验捕获数据相一致.
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