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Structure and Mechanism of Respiratory III-IV Supercomplexes in Bioenergetic Membranes.

ABSTRACT: In the final steps of energy conservation in aerobic organisms, free energy from electron transfer through the respiratory chain is transduced into a proton electrochemical gradient across a membrane. In mitochondria and many bacteria, reduction of the dioxygen electron acceptor is catalyzed by cytochrome c oxidase (complex IV), which receives electrons from cytochrome bc₁ (complex III), via membrane-bound or water-soluble cytochrome c. These complexes function independently, but in many organisms they associate to form supercomplexes. Here, we review the structural features and the functional significance of the nonobligate III₂IV_1/2 Saccharomyces cerevisiae mitochondrial supercomplex as well as the obligate III₂IV₂ supercomplex from actinobacteria. The analysis is centered around the Q-cycle of complex III, proton uptake by CytcO, as well as mechanistic and structural solutions to the electronic link between complexes III and IV.

SUBMITTER: Brzezinski P

PROVIDER: S-EPMC8361435 | biostudies-literature | 2021 Aug

REPOSITORIES: biostudies-literature

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Structure and Mechanism of Respiratory III-IV Supercomplexes in Bioenergetic Membranes.

Brzezinski Peter P Moe Agnes A Ädelroth Pia P

Chemical reviews 20210629 15

In the final steps of energy conservation in aerobic organisms, free energy from electron transfer through the respiratory chain is transduced into a proton electrochemical gradient across a membrane. In mitochondria and many bacteria, reduction of the dioxygen electron acceptor is catalyzed by cytochrome c oxidase (complex IV), which receives electrons from cytochrome bc1 (complex III), via membrane-bound or water-soluble cytochrome c. These complexes function in ...[more]

PMID: 34184881

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