6nkn
From Proteopedia
Time-resolved SFX structure of the PR intermediate of cytochrome c oxidase at room temperature
Structural highlights
FunctionCOX1_BOVIN Cytochrome c oxidase is the component of the respiratory chain that catalyzes the reduction of oxygen to water. Subunits 1-3 form the functional core of the enzyme complex. CO I is the catalytic subunit of the enzyme. Electrons originating in cytochrome c are transferred via the copper A center of subunit 2 and heme A of subunit 1 to the bimetallic center formed by heme A3 and copper B. Publication Abstract from PubMedCytochrome c oxidase (CcO) reduces dioxygen to water and harnesses the chemical energy to drive proton translocation across the inner mitochondrial membrane by an unresolved mechanism. By using time-resolved serial femtosecond crystallography, we identified a key oxygen intermediate of bovine CcO. It is assigned to the PR-intermediate, which is characterized by specific redox states of the metal centers and a distinct protein conformation. The heme a 3 iron atom is in a ferryl (Fe(4+) = O(2-)) configuration, and heme a and CuB are oxidized while CuA is reduced. A Helix-X segment is poised in an open conformational state; the heme a farnesyl sidechain is H-bonded to S382, and loop-I-II adopts a distinct structure. These data offer insights into the mechanism by which the oxygen chemistry is coupled to unidirectional proton translocation. Snapshot of an oxygen intermediate in the catalytic reaction of cytochrome c oxidase.,Ishigami I, Lewis-Ballester A, Echelmeier A, Brehm G, Zatsepin NA, Grant TD, Coe JD, Lisova S, Nelson G, Zhang S, Dobson ZF, Boutet S, Sierra RG, Batyuk A, Fromme P, Fromme R, Spence JCH, Ros A, Yeh SR, Rousseau DL Proc Natl Acad Sci U S A. 2019 Feb 26;116(9):3572-3577. doi:, 10.1073/pnas.1814526116. Epub 2019 Feb 11. PMID:30808749[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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