DOCKING AND ELECTRON-TRANSFER BETWEEN CYTOCHROME C(2) AND THE PHOTOSYNTHETIC REACTION-CENTER
DOCKING AND ELECTRON-TRANSFER BETWEEN CYTOCHROME C(2) AND THE PHOTOSYNTHETIC REACTION-CENTER
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DOI：
10.1016/0301-0104(95)00099-a
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发表时间：
1995-08-15
期刊：
影响因子：
2.3
通讯作者：
ONUCHIC, JN
中科院分区：
文献类型：
--
作者：
AQUINO, AJA;BEROZA, P;ONUCHIC, JN
利用Beratan和Onuchic的电子传递途径模型研究了细胞色素c（2）（cytc（2））与光合反应中心（RC）之间的电子传递。为了研究这种电子转移反应的蛋白质结构依赖性，我们将电子供体和受体之间的电子耦合衰减分为三个部分：（i）从细胞色素血红素到细胞色素表面的耦合，（ii）从RC表面到细菌叶绿素二聚体的耦合，以及（iii）从细胞色素表面到反应中心表面的耦合。计算表面氨基酸和氧化还原中心之间的耦合允许简单估计蛋白质间的电子耦合，并且对于给定的对接结构，提供了用于评估该结构的功能标准。Rps中最强的血红素到特殊电子对的电子传递途径。viridis（具有固定的血红素特殊对结构的RC）包括细胞色素和RC（当每个被视为单独的蛋白质时）上的表面残基，尽管它没有调用RC的最强耦合的表面原子。研究对接方向对Rb中电子转移的影响。sphaeroides，其中的细胞色素是不绑定到RC，我们产生的氧化还原位点和溶剂暴露的原子在每个蛋白质之间的电子耦合的表面耦合图。将这些图谱与两个对接的cytc（2）/RC结构计算的单个途径进行比较，一个基于静电互补，另一个基于最大化电子耦合。这两个对接结构的供体和受体之间的电子耦合是非常相似的，这表明有效的电子转移可以从非常不同的对接方向的细胞色素。讨论了影响分子间电子转移的其它因素。
Electron transfer between the proteins cytochrome c(2) (cytc(2)) and the photosynthetic reaction center (RC) was studied using the pathways model of Beratan and Onuchic. To investigate the protein structure dependence of this electron transfer reaction, we separated the electronic coupling decay between electron donor and acceptor into three parts: (i) the coupling from the cytochrome heme to the surface of the cytochrome, (ii) the coupling from the RC surface to the bacteriochlorophyll dimer, and (iii) the coupling from the surface of the cytochrome to the surface of the reaction center. Calculating the coupling between the surface amino acids and the redox center allows the simple estimate of inter-protein electronic coupling, and, for a given docked structure, provides a functional criterion for evaluating that structure. The strongest heme to special pair electron transfer pathway in Rps. viridis (an RC with fixed heme-special pair structure) included surface residues on the cytochrome and RC (when each was treated as a separate protein), although it did not invoke the most strongly coupled surface atoms of the RC. To examine the effect of docking orientation on electron transfer in Rb. sphaeroides, in which the cytochrome is not bound to the RC, we generated surface coupling maps of the electronic coupling between the redox sites and solvent exposed atoms in each protein. These maps were compared to individual pathways calculated for two docked cytc(2)/RC structures, one based on electrostatic complementarity, the other based on maximizing electronic coupling. The electronic coupling between donor and acceptor for these two docked structures was remarkably similar, suggesting that efficient electron transfer can be obtained from very different docked orientations of the cytochrome. Other factors influencing intermolecular electron transfer are discussed.