Conformational selectivity in cytochrome P450 redox partner interactions
Conformational selectivity in cytochrome P450 redox partner interactions
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DOI：
10.1073/pnas.1606474113
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发表时间：
2016-08-02
影响因子：
11.1
通讯作者：
Poulos, Thomas L.
中科院分区：
文献类型：
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作者：
Hollingsworth, Scott A.;Batabyal, Dipanwita;Poulos, Thomas L.
细胞色素 P450 的血红素铁必须被还原以结合并激活分子氧以进行底物氧化。还原当量源自氧化还原伙伴，这需要形成蛋白质-蛋白质复合物。越来越多的讨论的主题是氧化还原伙伴结合在促进活性所需的 P450 的显着结构变化方面所发挥的作用（如果有的话）。现在许多 P450 已被证明可以经历大的打开和关闭运动。多项结构和光谱研究表明，经过充分研究的 P450cam 在其氧化还原伙伴 Putidaredoxin (Pdx) 结合时采用开放构象，而最近的 NMR 研究表明这种观点是不正确的。鉴于这种差异与 P450 化学的相关性，确定 Pdx 是否倾向于 P450cam 的开放形式或封闭形式非常重要。在这里，我们使用了计算和实验等温滴定量热法研究，明确表明 Pdx 有利于与 P450cam 的开放形式结合。分子动力学轨迹的分析还提供了对可能与催化相关的中间构象状态的见解。
The heme iron of cytochromes P450 must be reduced to bind and activate molecular oxygen for substrate oxidation. Reducing equivalents are derived from a redox partner, which requires the formation of a protein-protein complex. A subject of increasing discussion is the role that redox partner binding plays, if any, in favoring significant structural changes in the P450s that are required for activity. Many P450s now have been shown to experience large open and closed motions. Several structural and spectral studies indicate that the well-studied P450cam adopts the open conformation when its redox partner, putidaredoxin (Pdx), binds, whereas recent NMR studies indicate that this view is incorrect. Given the relevance of this discrepancy to P450 chemistry, it is important to determine whether Pdx favors the open or closed form of P450cam. Here, we have used both computational and experimental isothermal titration calorimetry studies that unequivocally show Pdx favors binding to the open form of P450cam. Analyses of molecular-dynamic trajectories also provide insights into intermediate conformational states that could be relevant to catalysis.