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Cytochrome bcc-aa3 supercomplex (respiratory supercomplex III2/IV2) from Corynebacterium glutamicum (stigmatellin and azide bound)
Structural highlights
FunctionQCRA_CORGL Iron-sulfur subunit of the cytochrome bc1 complex, an essential component of the respiratory electron transport chain required for ATP synthesis. The bc1 complex catalyzes the oxidation of menaquinol and the reduction of cytochrome c in the respiratory chain. The bc1 complex operates through a Q-cycle mechanism that couples electron transfer to generation of the proton gradient that drives ATP synthesis.[1] [2] Publication Abstract from PubMedProton-translocating respiratory complexes assemble into supercomplexes that are proposed to increase the efficiency of energy conversion and limit the production of harmful reactive oxygen species during aerobic cellular respiration. Cytochrome bc complexes and cytochrome aa(3) oxidases are major drivers of the proton motive force that fuels ATP generation via respiration, but how wasteful electron- and proton transfer is controlled to enhance safety and efficiency in the context of supercomplexes is not known. Here, we address this question with the 2.8 A resolution cryo-EM structure of the cytochrome bcc-aa(3) (III(2)-IV(2)) supercomplex from the actinobacterium Corynebacterium glutamicum. Menaquinone, substrate mimics, lycopene, an unexpected Q(c) site, dioxygen, proton transfer routes, and conformational states of key protonable residues are resolved. Our results show how safe and efficient energy conversion is achieved in a respiratory supercomplex through controlled electron and proton transfer. The structure may guide the rational design of drugs against actinobacteria that cause diphtheria and tuberculosis. Structural basis for safe and efficient energy conversion in a respiratory supercomplex.,Kao WC, Ortmann de Percin Northumberland C, Cheng TC, Ortiz J, Durand A, von Loeffelholz O, Schilling O, Biniossek ML, Klaholz BP, Hunte C Nat Commun. 2022 Jan 27;13(1):545. doi: 10.1038/s41467-022-28179-x. PMID:35087070[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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