7jro
Plant Mitochondrial complex IV from Vigna radiata
Structural highlights
FunctionA0A1S3TZB2_VIGRR Component of the cytochrome c oxidase, the last enzyme in the mitochondrial electron transport chain which drives oxidative phosphorylation. The respiratory chain contains 3 multisubunit complexes succinate dehydrogenase (complex II, CII), ubiquinol-cytochrome c oxidoreductase (cytochrome b-c1 complex, complex III, CIII) and cytochrome c oxidase (complex IV, CIV), that cooperate to transfer electrons derived from NADH and succinate to molecular oxygen, creating an electrochemical gradient over the inner membrane that drives transmembrane transport and the ATP synthase. Cytochrome c oxidase is the component of the respiratory chain that catalyzes the reduction of oxygen to water. Electrons originating from reduced cytochrome c in the intermembrane space (IMS) are transferred via the dinuclear copper A center (CU(A)) of subunit 2 and heme A of subunit 1 to the active site in subunit 1, a binuclear center (BNC) formed by heme A3 and copper B (CU(B)). The BNC reduces molecular oxygen to 2 water molecules using 4 electrons from cytochrome c in the IMS and 4 protons from the mitochondrial matrix.[RuleBase:RU000457] Publication Abstract from PubMedMitochondrial complex III (CIII(2)) and complex IV (CIV), which can associate into a higher-order supercomplex (SC III(2)+IV), play key roles in respiration. However, structures of these plant complexes remain unknown. We present atomic models of CIII(2), CIV, and SC III(2)+IV from Vigna radiata determined by single-particle cryoEM. The structures reveal plant-specific differences in the MPP domain of CIII(2) and define the subunit composition of CIV. Conformational heterogeneity analysis of CIII(2) revealed long-range, coordinated movements across the complex, as well as the motion of CIII(2)'s iron-sulfur head domain. The CIV structure suggests that, in plants, proton translocation does not occur via the H channel. The supercomplex interface differs significantly from that in yeast and bacteria in its interacting subunits, angle of approach and limited interactions in the mitochondrial matrix. These structures challenge long-standing assumptions about the plant complexes and generate new mechanistic hypotheses. Atomic structures of respiratory complex III(2), complex IV, and supercomplex III(2)-IV from vascular plants.,Maldonado M, Guo F, Letts JA Elife. 2021 Jan 19;10:e62047. doi: 10.7554/eLife.62047. PMID:33463523[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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