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协调化学控制协酶B12 合成由人类腺三酸盐:Cob(I) 胺腺转移酶
Harsha Gouda1, Zhu Li1, Markus Ruetz1
1Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States.
Inorganic chemistry
|August 1, 2023
概括
这项研究揭示了MMAB酶如何使用紧张的四坐标cob(II) 胺结构来促进维生素B12的化学反应. 这种独特的几何结构对于减少辅因子至关重要,影响MMAB患者的疾病机制.
科学领域:
- 生物化学 生物化学
- 生物有机化学 生物有机化学
- 酶学 是一种酶学.
背景情况:
- 科巴胺 (维生素B12) 依赖的酶利用氧化还原连接的协调化学.
- 辅助因子的活性是由氧化状态和协调几何学控制的.
- 酶结合的可巴胺从六坐标变为四坐标 (4-c) 经历几何变化,因为从3+减少到1+.
研究的目的:
- 在人类腺三酸盐中强制执行不利的4-c cob 的热力学后果:cob 的alamin adenosyltransferase (MMAB).
- 为了确定MMAB活性部位内的4-c cob (II) 胺的降解潜力.
- 阐明上腺素作为电子捐赠者的作用,并了解MMAB变体中的致病机制.
主要方法:
- 实验确定4-c cob (II) 胺的降解潜力.
- 对MMAB结合的科巴胺进行光谱分析.
- 生物化学测试来评估从上腺素的电子转移.
主要成果:
- 在MMAB中,4-cc cob(II) 胺的降解潜力被确定为-325 ± 9 mV.
- 这一值比五坐标 (5-c) 水中结合的物种要积极得多 (180 mV).
- 与MMAB结合的cob (II) 胺的氧化还原潜力与上腺素作为电子供体兼容.
- 通过MMAB变体稳定5-c cob ((II) 胺会损害通过上腺素减少.
结论:
- 通过强制执行拉伸的4-c cob (II) 合金几何,MMAB获得了热力学优势.
- 确定的氧化还原潜能促进了必要的降解到超核友的胺中间体.
- 在MMAB变体中由于改变了科巴拉几何学的电子转移受到损害,这解释了疾病的发病原因.
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