Ukolova I V
Сибирский институт физиологии и биохимии растений Сибирского отделения Российской академии наук, Иркутск, Россия.
Vavilovskii Zhurnal Genet Selektsii. 2021 Nov;25(7):778-786. doi: 10.18699/VJ21.089.
The oxidative phosphorylation (OXPHOS) system of mitochondria supports all the vitally important energy-consuming processes in eukaryotic cells, providing them with energy in the form of ATP. OXPHOS enzymes (complexes I-V) are located in the inner mitochondrial membrane, mainly in the cristae subcompartment. At present, there is a large body of data evidencing that the respiratory complexes I, III2 and IV under in vivo conditions can physically interact with each other in diverse stoichiometry, thereby forming supercomplexes. Despite active accumulation of knowledge about the structure of the main supercomplexes of the OXPHOS system, its physical and functional organization in vivo remains unclear. Contemporary models of the OXPHOS system's organization in the inner membrane of mitochondria are contradictory and presume the existence of either highly organized respiratory strings, or, by contrast, a set of randomly dispersed respiratory supercomplexes and complexes. Furthermore, it is assumed that ATP-synthase (complex V) does not form associations with respiratory enzymes and operates autonomously. Our latest data obtained on mitochondria of etiolated shoots of pea evidence the possibility of physical association between the respiratory supercomplexes and dimeric ATP-synthase. These data have allowed us to reconsider the contemporary concept of the phosphorylation system organization and propose a new subcompartmented oxphosomic model. According to this model, a substantial number of the OXPHOS complexes form oxphosomes, which in a def inite stoichiometry include complexes I-V and are located predominantly in the cristae subcompartment of mitochondria in the form of highly organized strings or patches. These suprastructures represent "mini-factories" for ATP production. It is assumed that such an organization (1) contributes to increasing the eff iciency of the OXPHOS system operation, (2) involves new levels of activity regulation, and (3) may determine the inner membrane morphology to some extent. The review discusses the proposed model in detail. For a better understanding of the matter, the history of development of concepts concerning the OXPHOS organization with the emphasis on recent contemporary models is brief ly considered. The principal experimental data accumulated over the past 40 years, which conf irm the validity of the oxphosomic hypothesis, are also provided.
线粒体的氧化磷酸化（OXPHOS）系统支持真核细胞中所有至关重要的能量消耗过程，以ATP的形式为细胞提供能量。OXPHOS酶（复合体I-V）位于线粒体内膜，主要存在于嵴亚区室中。目前，大量数据表明，在体内条件下，呼吸复合体I、III2和IV能够以不同的化学计量比相互物理作用，从而形成超复合体。尽管关于OXPHOS系统主要超复合体结构的知识在不断积累，但其在体内的物理和功能组织仍不清楚。当代关于线粒体内膜中OXPHOS系统组织的模型相互矛盾，要么假定存在高度组织化的呼吸链，要么相反，认为存在一组随机分散的呼吸超复合体和复合体。此外，人们认为ATP合酶（复合体V）不与呼吸酶形成关联，而是自主运作。我们最近在豌豆黄化苗线粒体上获得的数据证明了呼吸超复合体与二聚体ATP合酶之间存在物理关联的可能性。这些数据使我们能够重新审视当代关于磷酸化系统组织的概念，并提出一种新的亚区室化氧化磷酸化体模型。根据该模型，大量的OXPHOS复合体形成氧化磷酸化体，这些氧化磷酸化体以确定的化学计量比包含复合体I-V，并且主要以高度组织化的链或斑块的形式位于线粒体的嵴亚区室中。这些超结构代表了ATP产生的“微型工厂”。据推测，这样的组织（1）有助于提高OXPHOS系统的运行效率，（2）涉及新的活性调节水平，（3）可能在一定程度上决定内膜形态。本文详细讨论了所提出的模型。为了更好地理解这一问题，简要回顾了关于OXPHOS组织概念的发展历程，重点是当代最新模型。还提供了过去40年积累的主要实验数据，这些数据证实了氧化磷酸化体假说的有效性。
