Manchester Institute of Biotechnology and School of Chemistry, University of Manchester, UK.
FEBS J. 2019 Jun;286(11):2004-2017. doi: 10.1111/febs.14757. Epub 2019 Jan 30.
How the dynamics of proteins assist catalysis is a contemporary issue in enzymology. In particular, this holds true for membrane-bound enzymes, where multiple structural, spectroscopic and biochemical approaches are needed to build up a comprehensive picture of how dynamics influence enzyme reaction cycles. Of note are the recent studies of cytochrome P450 reductases (CPR)-P450 (CYP) endoplasmic reticulum redox chains, showing the relationship between dynamics and electron flow through flavin and haem redox centres and the impact this has on monooxygenation chemistry. These studies have led to deeper understanding of mechanisms of electron flow, including the timing and control of electron delivery to protein-bound cofactors needed to facilitate CYP-catalysed reactions. Individual and multiple component systems have been used to capture biochemical behaviour and these have led to the emergence of more integrated models of catalysis. Crucially, the effects of membrane environment and composition on reaction cycle chemistry have also been probed, including effects on coenzyme binding/release, thermodynamic control of electron transfer, conformational coupling between partner proteins and vectorial versus 'off pathway' electron flow. Here, we review these studies and discuss evidence for the emergence of dynamic structural models of electron flow along human microsomal CPR-P450 redox chains.
蛋白质动力学如何协助催化是当前酶学的一个问题。特别是对于膜结合酶，需要采用多种结构、光谱和生化方法，才能全面了解动力学如何影响酶反应循环。值得注意的是，最近对细胞色素 P450 还原酶 (CPR)-P450 (CYP) 内质网氧化还原链的研究表明，动力学与黄素和血红素氧化还原中心的电子流之间存在关系，以及这对单加氧化学的影响。这些研究加深了对电子流机制的理解，包括向蛋白结合辅因子传递电子的时间和控制，以促进 CYP 催化反应。已经使用单个和多个组件系统来捕获生化行为，这导致了更综合的催化模型的出现。至关重要的是，还研究了膜环境和组成对反应循环化学的影响，包括对辅酶结合/释放、电子转移的热力学控制、伴侣蛋白之间的构象偶联以及向量与“非路径”电子流的影响。在这里，我们回顾这些研究，并讨论沿人类微粒体 CPR-P450 氧化还原链出现动态结构电子流模型的证据。
