Abstract Here, we studied the interaction of Cys-substituted (G56C) cytochrome c labeled with sulfocyanin-3 fluorescent dye (fCyt) with artificial and natural lipid membranes by using fluorescence correlation spectroscopy (FCS). Compared to mitochondria, mitoplasts were shown to have more fCyt binding sites with a lower affinity for this protein. The fCyt affinity for cardiolipin-containing liposomes depended on the content of cardiolipin in liposomes and decreased upon raising the ionic strength of the solution. A high value of the constant of the fCyt binding with mitochondria could be explained by the presence of specific binding sites for this protein on the mitochondrial outer membrane surface. This explanation is confirmed by observation of more efficient displacement of fluorescent cytochrome c by the unlabeled mutant variant K8T than by the WT protein, whereas in mitoplasts and liposomes the WT protein displaced fCyt more efficiently than K8T.

中文翻译：

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荧光相关光谱法研究荧光细胞色素 C 与脂质体、线粒体和线粒体的相互作用

摘要 在这里，我们使用荧光相关光谱 (FCS) 研究了用 sulfocyanin-3 荧光染料 (fCyt) 标记的 Cys 取代 (G56C) 细胞色素 c 与人工和天然脂质膜的相互作用。与线粒体相比，线粒体具有更多的 fCyt 结合位点，但对这种蛋白质的亲和力较低。fCyt 对含心磷脂脂质体的亲和力取决于脂质体中心磷脂的含量，并随着溶液离子强度的提高而降低。fCyt 与线粒体结合的常数的高值可以解释为在线粒体外膜表面存在该蛋白质的特异性结合位点。