Dian Elke A, Papatheodorou Panagiotis, Emmrich Kerstin, Randel Olga, Geissler Andreas, Kölling Ralf, Rassow Joachim, Motz Christian
Institut für Physiologische Chemie, Abteilung für Zellbiochemie, Ruhr-Universität Bochum, MA 3/40, D-44780 Bochum, Germany.
J Mol Biol. 2008 Apr 11;377(5):1314-23. doi: 10.1016/j.jmb.2008.02.005. Epub 2008 Feb 12.
The gamma-subunit is required for the assembly of ATP synthases and plays a crucial role in their catalytic activity. We stepwise shortened the N-terminus and the C-terminus of the gamma-subunit in the mitochondrial ATP synthase of yeast and investigated the relevance of these segments in the assembly of the enzyme and in the growth of the cells. We found that a deletion of 9 residues at the N-terminus or 20 residues at the C-terminus still allowed efficient import of the subunit into mitochondria; however, the assembly of both monomeric and dimeric holoenzymes was partially impaired. gamma-Subunits lacking 13 N-terminal residues or 30 C-terminal residues were not assembled. Yeast strains expressing either of the truncated gamma-subunits did not grow on non-fermentable carbon sources, indicating that non-assembled parts of the ATP synthase accumulated and impaired essential mitochondrial functions.
γ亚基是ATP合酶组装所必需的，并且在其催化活性中起关键作用。我们逐步缩短了酵母线粒体ATP合酶中γ亚基的N端和C端，并研究了这些片段在酶组装和细胞生长中的相关性。我们发现，N端缺失9个残基或C端缺失20个残基仍能使该亚基高效导入线粒体；然而，单体和二聚体全酶的组装均受到部分损害。缺少13个N端残基或30个C端残基的γ亚基无法组装。表达任一截短γ亚基的酵母菌株在非发酵碳源上均无法生长，这表明ATP合酶未组装的部分积累并损害了基本的线粒体功能。
