非血红素Fe的异常催化策略 (二) /2-氧格酸盐依赖的阿斯巴提尔氧酶AspH
Anandhu Krishnan1, Sodiq O Waheed1, Ann Varghese1
1Department of Chemistry, Michigan Technological University Houghton MI 49931 USA tatyanak@mtu.edu.
AspH酶使用独特的铁结合水分子进行立体选择性C-H化,与其他2 - 氧格酸盐 (2OG) 化酶不同. 这种机制涉及原子转移和反弹步骤,为生物催化剂工程提供了洞察力.
科学领域:
- 生物化学 生物化学
- 酶学 是一种酶学.
- 有机化学 有机化学
背景情况:
- 生物催化C-H氧化对于合成有机分子和基本细胞过程至关重要.
- 非血红素Fe (II) /2-oxoglutarate (2OG) 依赖的氧化酶是这些反应中的关键酶.
- AspH酶氧化阿斯巴提尔和阿斯巴拉基尼尔残留物以立体选择的方式.
研究的目的:
- 阐明AspH酶的独特催化机制.
- 了解铁协调水分子和第二协调球 (SCS) 残留物在AspH催化中的作用.
- 调查AspH.中四基重复 (TPR) 域的立体选择性决定因素和动态.
主要方法:
- 进行X射线晶体学以确定AspH结构.
- 分子动力学 (MD) 模拟用于研究酶动力学和水分子稳定.
- 量子力学/分子力学 (QM/MM) 研究分析催化机制.
- 对基质定位和与SCS残留物非共价相互作用的分析.
主要成果:
- AspH具有与水分子的独特Fe (II) 协调,而不是典型的碳酸盐残留物.
- 在第二个协调球 (SCS) 中,铁协调水通过与Asp721的键稳定.
- 催化过程通过二氧化物激活,原子转移 (HAT) 和反弹化,反弹阶段可能限制速度.
- 立体选择性由HAT和基质定位通过SCS残留控制,可能保留配置.
- TPR 域影响基质结合,并在催化过程中表现出动态运动.
结论:
- AspH采用一种新的催化策略,使用协调的水分子进行立体选择性氧化.
- SCS残留物在稳定铁中心和指导立体控制的基板结合方面发挥着至关重要的作用.
- 了解AspH的机制可以指导酶工程用于立体选择生物催化剂和生物模拟催化剂的开发.
- 这些发现表明,2OG氧化酶超级家族内的多样性可能比以前认可的更广泛.
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