6pw0
Cytochrome C oxidase delta 6 mutantCytochrome C oxidase delta 6 mutant
Structural highlights
Function[Q3J5G0_RHOS4] Subunits I and II form the functional core of the enzyme complex. Electrons originating in cytochrome c are transferred via heme a and Cu(A) to the binuclear center formed by heme a3 and Cu(B).[RuleBase:RU004024] Publication Abstract from PubMedData from earlier studies showed that minor structural changes at the surface of cytochrome c oxidase, near one of the proton-input pathways (the D pathway), result in dramatically decreased activity and a lower proton-pumping stoichiometry. To further investigate how changes around the D pathway orifice influence functionality of the enzyme, here we modified the nearby C-terminal loop of subunit I of the Rhodobacter sphaeroides cytochrome c oxidase. Removal of 16 residues form this flexible surface loop resulted in a decrease in the proton-pumping stoichiometry to <50% of that of the wild-type enzyme. Replacement of the protonatable residue Glu552, part of the same loop, by an Ala, resulted in a similar decrease in the proton-pumping stoichiometry without loss of the O2-reduction activity or changes in the proton-uptake kinetics. The data show that minor structural changes at the orifice of the D pathway, at a distance of ~40A from the proton gate of cytochrome c oxidase, may alter the proton-pumping stoichiometry of the enzyme. Structural changes at the surface of cytochrome c oxidase alter the proton-pumping stoichiometry.,Berg J, Liu J, Svahn E, Ferguson-Miller S, Brzezinski P Biochim Biophys Acta Bioenerg. 2019 Nov 13:148116. doi:, 10.1016/j.bbabio.2019.148116. PMID:31733183[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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