Zanotti Franco, Raho Gabriella, Gaballo Antonio, Papa Sergio
Department of Medical Biochemistry and Biology, University of Bari, Italy.
J Bioenerg Biomembr. 2004 Oct;36(5):447-57. doi: 10.1023/B:JOBB.0000047327.68173.9b.
The inhibitor protein IF1 is a basic protein of 84 residues which inhibits the ATPase activity of the mitochondrial FoF1-ATP synthase complex without having any effect on ATP synthesis. Results of cross-linking and limited proteolysis experiments are presented showing that in the intact FoF1 complex "in situ," in the inner membrane of bovine heart mitochondria, the central segment of IF1 (residues 42-58) binds to the alpha and beta subunits of F1 in a pH dependent process, and inhibits the ATPase activity. The C-terminal region of IF1 binds, simultaneously, to the OSCP subunit of Fo in a pH-independent process. This binding keeps IF1 anchored to the complex, both under inhibitory conditions, at acidic pH, and noninhibitory conditions at alkaline pH.
抑制蛋白IF1是一种由84个氨基酸残基组成的碱性蛋白，它能抑制线粒体F₀F₁ - ATP合酶复合物的ATP酶活性，而对ATP合成没有任何影响。本文展示了交联和有限蛋白酶解实验的结果，表明在牛心线粒体内膜完整的“原位”F₁复合物中，IF1的中央片段（42 - 58位氨基酸残基）在一个pH依赖的过程中与F₁的α和β亚基结合，并抑制ATP酶活性。IF1的C末端区域同时在一个pH不依赖的过程中与F₀的OSCP亚基结合。这种结合使IF1在酸性pH的抑制条件下和碱性pH的非抑制条件下都能锚定在复合物上。
