Respiratory chain supercomplexes of mitochondria and bacteria
Respiratory chain supercomplexes of mitochondria and bacteria
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DOI：
10.1016/s0005-2728(02)00271-2
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发表时间：
2002-09-10
影响因子：
4.3
通讯作者：
Schägger, H
中科院分区：
文献类型：
--
作者：
Schägger, H
呼吸链复合体是存在于细菌和线粒体膜中的较大结构和功能单位的片段，呼吸链超复合体或“呼吸体”。线粒体和细菌的超复合体含有复合体III、IV和复合体I，但酿酒酵母除外，它不含复合体I。这些超复合体通常对超声波稳定，但对除洋地黄素以外的大多数洗涤剂敏感。在S.ecrevisiae，一项试验。或将络合物III和IV连接在一起的成分是心磷脂。在脱氮副球藻中，络合物I本身对洗涤剂相当敏感，因此到目前为止还不能以洗涤剂溶解的形式获得。然而，它可以被分离出来，作为超复合体的一部分。在人类线粒体中也发现了通过与络合物III结合来稳定络合物I的作用。在超络合物中，组织的进一步功能作用是通过减少底物的扩散距离来催化增强，或者根据有机体的不同，引导底物的苯醌和细胞色素c。这使得氧化还原反应对底物的中点电位的依赖性较小，并允许电子在底物还原程度较低的情况下流动。ATP合酶的二聚体状态似乎是线粒体所特有的。单体三磷酸腺苷合成酶仅在伍迪醋杆菌、脱氮假单胞菌和菠菜叶绿体中发现。(C)2002 Elsevier Science B.V.保留所有权利。
Respiratory chain complexes are fragments of larger structural and functional units, the respiratory chain supercomplexes or "respirasomes", which exist in bacterial and mitochondrial membranes. Supercomplexes of mitochondria and bacteria contain complexes III, IV, and complex I, with the notable exception of Saccharomyces cerevisiae, which does not possess complex I. These supercomplexes often are stable to sonication but sensitive to most detergents except digitonin. In S. ecrevisiae, a trial. or component linking complexes III and IV together is cardiolipin. In Paracoccus denitrificans, complex I itself is rather detergent-sensitive and thus could not be obtained in detergent-solubilized form so far. However, it can be isolated as part of a supercomplex. Stabilization of complex I by binding to complex III was also found in human mitochondria. Further functional roles of the organization in a supercomplex are catalytic enhancement by reducing diffusion distances of substrates or, depending on the organism, channelling of the substrates quinone and cytochrome c. This makes redox reactions less dependent of midpoint potentials of substrates, and permits electron flow at low degree of substrate reduction. A dimeric state of ATP synthase seems to be specific for mitochondria. Exclusively, monomeric ATP synthase was found in Acetobacterium woodii, in P denitrificans, and in spinach chloroplasts. (C) 2002 Elsevier Science B.V. All rights reserved.