THEORY OF PROTEIN/PROTEIN ASSOCIATION

蛋白质-蛋白质缔合是多种生物学中的中心事件， 生物过程包括酶催化/抑制和电子 运输 用于形成立体特异性的取向约束 复杂性严重限制了关联率。静电 相互作用能够补偿这种限制并增强 速率高达四个数量级。 通过一系列 理论和计算研究，首席研究员 最近已经表明，扩散的静电增强- 受影响的缔合速率可以通过自由能来预测。 用于形成立体特异性络合物的“过渡态”。 建立 这是一种真正的预测计算方法， 关联，本文提出的过渡态的结构模型 将根据实验结果进行改进和验证， 电荷突变和离子强度对几种蛋白质的影响 配合物 其中包括巴纳斯-巴斯塔综合体， 与英国医学研究理事会的Alan Fersht博士合作 将允许测试预测的突变效应。 作为 细胞色素c和细胞色素的结合与解离 c过氧化物酶将被研究，以帮助解决目前的争论， 电子转移的限速步骤和突变的影响 对血红蛋白α β二聚体组装率的影响 定量确定，以说明 杂合子红细胞中的正常和变异血红蛋白。 对 在定性层面，可以设想， 过渡状态将作为理解 单个氨基酸对蛋白质-蛋白质缔合的贡献。

Protein-protein association is a central event in a diverse range of biological processes including enzyme catalysis/inhibition and electron transport. The orientational constraints for forming a stereospecific complex severely restrict the rate of association. Electrostatic interactions are able to compensate for such restriction and enhance the rate by as much as four orders of magnitude. Through a series of theoretical and computational studies, the principal investigator recently has shown that the electrostatic enhancement of the diffusion- influenced association rate can be predicted by the free energy of a "transition state" for forming the stereospecific complex. To establish this as a truly predictive computational approach to protein-protein association, a structural model for the transition state proposed herein will be refined and validated against experimental results for the effects of charge mutations and ionic strength on several protein complexes. These include the barnaes-barstar complex, on which ongoing collaboration with Dr. Alan Fersht of the UK Medical Research Council will allow for predicted mutational effects to be tested. As applications, association and dissociation of cytochrome c and cytchrome c peroxidase will be studied to help settle the current debate about the rate-limiting step for electron transfer and the effects of mutations on the rate of hemoglobin AlphaBeta dimer assembly will be quantitatively determined to account for the relative proportions of normal and variant hemoglobins in red blood cells of heterozygotes. On a qualitative level, it is envisioned that the structural model for the transition state will serve as a guide for understanding the contributions of individual amino acids to protein-protein association.