与FeMo辅助因子结合的连接物:CO结合和活性化酶的结构
Thomas Spatzal1, Kathryn A Perez2, Oliver Einsle3
1Howard Hughes Medical Institute and Division of Chemistry and Chemical Engineering, MailCode 114-96, California Institute of Technology, Pasadena, CA 91125, USA. spatzal@caltech.edu dcrees@caltech.edu.
概括
一氧化碳 (CO) 通过与铁-联合因子 (FeMo联合因子) 结合,可逆地抑制基酶. 这项结构研究揭示了CO结合导致了显著的可逆的辅因子重组,揭示了反应性铁物种.
科学领域:
- 生物化学 生物化学
- 结构生物学 结构生物学
- 酶的机制 酶的机制
背景情况:
- 酶酶复合物催化了关键的气转化为氨的过程.
- 了解基质和抑制剂与酶活性部位结合的精确机制仍然是一个重大挑战.
研究的目的:
- 阐明一氧化碳 (CO) 抑制在酶铁 (MoFe) 蛋白中的结合方式和结构后果.
主要方法:
- 使用X射线晶体学来确定CO抑制和活性化酶MoFe蛋白的高分辨率结构.
- 对FeMo辅助因子结构的分析,以确定抑制剂结合部位和辅助因子重排.
主要成果:
- 在1.50安格斯特罗姆分辨率的晶体结构中,发现一氧化碳 (CO) 在FeMo辅因子中桥接Fe2和Fe6,取代了一颗硫原子 (S2B).
- 这种结合诱导了微2几何,并暴露了反应性铁物种.
- 酶活性恢复了,S2B原子在重新激活的酶的1.43安格斯特罗姆分辨率结构中重新出现,证明了可逆的CO抑制.
结论:
- 一氧化碳 (CO) 抑制基酶涉及到FeMo辅因子的实质性和可逆性结构重组.
- 硫的位移和对反应性铁物种的暴露为酶的催化循环和潜在的活性状态提供了新的见解.
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