The Coupling of Protonation and Reduction in Proteins with Multiple Redox Centers: Theory, Computational Method, and Application to Cytochrome c3
The Coupling of Protonation and Reduction in Proteins with Multiple Redox Centers: Theory, Computational Method, and Application to Cytochrome c3
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具有多个氧化还原中心的蛋白质质子化和还原的耦合：理论、计算方法及其在细胞色素 c3 中的应用
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发表时间：
2000
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通讯作者：
G. Ullmann
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作者：
G. Ullmann
质子化和还原的耦合在许多生物电荷转移反应中是至关重要的，被称为氧化还原玻尔效应。它是由质子化和氧化还原活性基团之间的静电相互作用引起的。在这项研究中，我描述了一种方法来计算质子化和氧化的概率取决于溶液的pH值和氧化还原电位。能量计算基于线性化的泊松-玻尔兹曼方程。氧化和质子化概率的实际计算是用混合统计力学/Tanford-Roxby方法完成的。该方法适用于细胞色素c3，一种结合四个血红素的小蛋白质。已知该蛋白质用于将质子化与还原反应偶联。血红素I的丙酸盐D显示其质子化概率的最强氧化还原电位依赖性，因此最有可能是负责氧化还原玻尔效应。计算结果与实验数据吻合较好。由于许多可滴定物质之间的相互作用...
The coupling of protonation and reduction is crucial in many biological charge transfer reactions and is known as redox Bohr effect. It is caused by electrostatic interactions between protonatable and redox-active groups. In this study, I describe a method to calculate protonation and oxidation probabilities depending on the solution pH and redox potential. The energetic calculations are based on the linearized Poisson−Boltzmann equation. The actual calculation of the oxidation and protonation probabilities is done with a hybrid statistical mechanics/Tanford−Roxby approach. The method is applied to cytochrome c3, a small protein that binds four hemes. The protein is known for coupling a protonation to the reduction reactions. The propionate D of heme I shows the strongest redox potential dependence of its protonation probability and is thus most likely responsible for the redox Bohr effect. The computational results agree well with experimental data. Because of the interactions between the many titratable...