Dipartimento di Biochimica "G. Moruzzi," Alma Mater Studiorum, Università di Bologna, Bologna, Italy.
Antioxid Redox Signal. 2010 Apr 15;12(8):961-1008. doi: 10.1089/ars.2009.2704.
The enzymatic complexes of the mitochondrial respiratory chain have been extensively investigated in their structural and functional properties. A clear distinction is possible today between three complexes in which the difference in redox potential allows proton translocation (complexes I, III, and IV) and those having the mere function to convey electrons to the respiratory chain. We also have a clearer understanding of the structure and function of most respiratory complexes, of their biogenesis and regulation, and of their capacity to generate reactive oxygen species. Past investigations led to the conclusion that the complexes are randomly dispersed and functionally connected by diffusion of smaller redox components, coenzyme Q and cytochrome c. More-recent investigations by native gel electrophoresis and single-particle image processing showed the existence of supramolecular associations. Flux-control analysis demonstrated that complexes I and III in mammals and I, III, and IV in plants kinetically behave as single units, suggesting the existence of substrate channeling. This review discusses conditions affecting the formation of supercomplexes that, besides kinetic advantage, have a role in the stability and assembly of the individual complexes and in preventing excess oxygen radical formation. Disruption of supercomplex organization may lead to functional derangements responsible for pathologic changes.
线粒体呼吸链的酶复合物在其结构和功能特性方面已经得到了广泛的研究。今天，我们可以清楚地区分三种复合物，其中氧化还原电位的差异允许质子转移（复合物 I、III 和 IV），而那些仅仅具有将电子传递给呼吸链的功能。我们对大多数呼吸复合物的结构和功能、它们的生物发生和调节以及它们产生活性氧的能力有了更清晰的认识。过去的研究得出的结论是，复合物是通过较小的氧化还原成分（辅酶 Q 和细胞色素 c）的扩散随机分散和功能连接的。最近通过天然凝胶电泳和单颗粒图像处理的研究表明存在超分子缔合。通量控制分析表明，哺乳动物中的复合物 I 和 III 以及植物中的 I、III 和 IV 在动力学上表现为单个单元，这表明存在底物通道化。这篇综述讨论了影响超复合物形成的条件，除了动力学优势外，超复合物的形成还有助于单个复合物的稳定性和组装，并防止过多的氧自由基形成。超复合物组织的破坏可能导致负责病理变化的功能障碍。
