不同类型的协同作用对1型铜活性位点的超交换通路的贡献
Ryan G Hadt1, Serge I Gorelsky, Edward I Solomon
1Department of Chemistry, Stanford University , Stanford, California 94305, United States.
Journal of the American Chemical Society
|October 14, 2014
概括
电子转移蛋白中铜-硫键的共价性激活了有效电子转移的途径. 不同的铜位点类型选择性地使用这些通路,优化酸盐减少酶和多铜氧化酶中的酶功能.
科学领域:
- 生物化学 生物化学
- 生物有机化学 生物有机化学
- 酶催化酶的催化作用
背景情况:
- 1型 (T1) 铜位点对于酸盐减少酶 (NiRs) 和多铜氧化酶 (MCOs) 等酶的电子转移 (ET) 是至关重要的.
- 这些T1位点通过囊胺-胺 (Cys-His) 桥梁连接到催化中心,提供两个潜在的ET通道 (P1和P2).
研究的目的:
- 研究T1铜位点的电子结构如何影响分子内电子转移.
- 阐明T1铜-硫键共价性在激活ET通路中的作用.
- 了解酶特异性环境如何调节这些ET通路以实现高效的催化.
主要方法:
- 电子合和超交换机制的计算分析.
- 对T1铜位结构及其对应的ET路径在NiR和MCO中的比较.
主要成果:
- T1铜硫键的高共价性通过Cys-His桥激活了通过Cys-His桥的孔超交换.
- 这种共价活性电子合 (HDA) 通过P1 (蛋白质骨干) 和P2 (H键) 途径促进长距离ET.
- 在NiR中,蓝色 (π型) T1站点主要使用P1,而绿色 (σ型) T1站点使用更有效的P2路径.
- 在MCO中,周围的蛋白质环境改变了Cys-His通路的形状,有利于蓝色π位的HDA和高效的催化.
结论:
- 金属结合体键的异构共价性决定了首选的ET路径和电子合强度.
- 蛋白质环境动态调整这些通路,使得选择性激活超级交换以实现最佳的酶功能.
- Cys-His桥是ET的多功能调解器,可以通过电子合的调制来适应不同的催化需求.
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