Komar-Panicucci S, Sherman F, McLendon G
Department of Chemistry, Princeton University, New Jersey 08544-1009, USA.
Biochemistry. 1996 Apr 16;35(15):4878-85. doi: 10.1021/bi952771z.
According to Marcus' theory, rates of electron transfer reactions depend parabolically on the free energy of reaction. Amino acid replacements in the electron transport protein cytochrome c produced a series of proteins which changed the free energy of reaction for cytochrome c in oxidative phosphorylation. This study shows that Marcus' theory of electron transfer can be applied to the reactions of redox-altered cytochromes c with cytochrome c1 both in vitro and in vivo. In vitro, isolation of physiologically relevant partners of cytochrome c suggests that a change in free energy of reaction of cytochrome c changes the rate of electron transfer with cytochrome bc1 complex as would be predicted by Marcus' theory of electron transfer. Furthermore, the reactivity pattern observed in vitro is paralleled in in vivo studies. In vivo the rates of growth of Saccharomyces cerevisiae, in which these alternatives have been incorporated, also are consistent with the change in free energy of the reactions of cytochrome c with cytochrome bc1 complex. This study suggests that Marcus' theory of electron transport can predict rates not only in vitro, in isolated protein-protein systems, but also in vivo, where the relative growth rates of yeast may be predicted from the in vitro results.
根据马库斯理论，电子转移反应速率与反应自由能呈抛物线关系。电子传递蛋白细胞色素c中的氨基酸替换产生了一系列蛋白质，这些蛋白质改变了氧化磷酸化过程中细胞色素c的反应自由能。本研究表明，马库斯电子转移理论可应用于氧化还原改变的细胞色素c与细胞色素c1在体外和体内的反应。在体外，分离细胞色素c的生理相关伴侣表明，细胞色素c反应自由能的变化会改变与细胞色素bc1复合物的电子转移速率，正如马库斯电子转移理论所预测的那样。此外，体外观察到的反应模式在体内研究中也有体现。在体内，含有这些替代物的酿酒酵母的生长速率也与细胞色素c与细胞色素bc1复合物反应的自由能变化一致。本研究表明，马库斯电子传递理论不仅可以预测体外分离的蛋白质-蛋白质系统中的反应速率，还可以预测体内酵母相对生长速率，其可根据体外结果进行预测。
