Protein-Protein Orientation and Dynamics in Electron-Transfer Reactions

9222741 Kostic本研究的目的是了解静电（非共价）蛋白质/蛋白质复合物中的电子转移机制。 最佳反应速率和特异性的分子基础将与充分表征的金属蛋白细胞色素c（cyt）和质体蓝素（pc）一起研究。 基于这个实验室最近的成功，提出了一个详细的计划，结合分子生物学（突变的pc），计算化学（电子转移路径分析）和动力学（激光闪光光解）以实现以下：（1）确定cyt/pc复合物的反应性取向;（2）精确定位从血红素到Cu位点的主要转移路径;（3）研究远距离电子耦合的变化如何控制电子转移的速率;（4）确定cyt/pc复合物的结构重排速率，并建立“门控”的动力学要求;（5）探索蛋白质/蛋白质界面构象波动对电子转移的重要性。 这项研究很重要，因为金属蛋白的电子转移反应对各种生物过程至关重要。 这些反应涉及动物新陈代谢和植物光合作用。 在分子水平上更深入地理解电子转移，对于更好地理解活细胞中化学能的起源和转化是必要的。 ***

9222741 Kostic The objective of this research is to understand the mechanism of electron transfer in electrostatic (noncovalent) protein/protein complexes. The molecular basis for the optimal reaction rate and specificity will be studied with the fully-characterized metalloproteins cytochrome c (cyt) and plastocyanin (pc). Building upon this laboratory's recent successes, a detailed plan is proposed that combines molecular biology (mutation of pc), computational chemistry (analysis of electron-transfer paths), and kinetics (laser flash photolysis) in order to achieve the following: (1) determine reactive orientations of cyt/pc complexes; (2) pinpoint dominant transfer paths from the heme to the Cu site; (3) examine how variations in distant electronic couplings controls the rate of electron transfer; (4) determine the rate of structural rearrangement of cyt/pc complexes and establish kinetic requirements for "gating"; and (5) explore the importance for electron transfer of conformational fluctuations at the protein/protein interface. %%% This research is important because electron-transfer reactions of metalloproteins are essential to various biological processes. These reactions are involved in animal metabolism and plant photosynthesis. A deeper understanding of electron transfer, at the molecular level, is necessary for a better understanding of the origin and transformations of chemical energy in a living cell. ***