Max Planck Institute of Molecular Plant Physiology, Energy Metabolism Research Group, Am Mühlenberg 1, D-14476, Potsdam, Germany.
J Biol Chem. 2011 Dec 16;286(50):43045-53. doi: 10.1074/jbc.M111.252544. Epub 2011 Oct 18.
Respiratory supercomplexes are large protein structures formed by various enzyme complexes of the mitochondrial electron transport chain. Using native gel electrophoresis and activity staining, differential regulation of complex activity within the supercomplexes was investigated. During prolonged hypoxia, complex I activity within supercomplexes diminished, whereas the activity of the individual complex I-monomer increased. Concomitantly, an increased activity was observed during hypoxia for complex IV in the smaller supercomplexes that do not contain complex I. These changes in complex activity within supercomplexes reverted again during recovery from the hypoxic treatment. Acidification of the mitochondrial matrix induced similar changes in complex activity within the supercomplexes. It is suggested that the increased activity of the small supercomplex III(2)+IV can be explained by the dissociation of complex I from the large supercomplexes. This is discussed to be part of a mechanism regulating the involvement of the alternative NADH dehydrogenases, known to be activated by low pH, and complex I, which is inhibited by low pH. It is concluded that the activity of complexes within supercomplexes can be regulated depending on the oxygen status and the pH of the mitochondrial matrix.
呼吸超级复合物是由线粒体电子传递链的各种酶复合物组成的大型蛋白质结构。使用天然凝胶电泳和活性染色，研究了超级复合物中复合物活性的差异调节。在长时间的缺氧期间，超级复合物内的复合物 I 活性降低，而单体复合物 I 的活性增加。同时，在不包含复合物 I 的较小超级复合物中，复合物 IV 的活性在缺氧期间增加。超级复合物内复合物活性的这些变化在从缺氧处理中恢复时再次逆转。线粒体基质的酸化诱导超级复合物内复合物活性的类似变化。有人认为，小超级复合物 III(2)+IV 的活性增加可以通过复合物 I 从大型超级复合物中解离来解释。这被认为是调节已知被低 pH 激活的替代 NADH 脱氢酶以及被低 pH 抑制的复合物 I 参与的机制的一部分。结论是，超级复合物内复合物的活性可以根据氧状态和线粒体基质的 pH 进行调节。
