[COX1_RHOSH] 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. This cytochrome c oxidase shows proton pump activity across the membrane in addition to the electron transfer. [COX2_RHOSH] 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).
Micromolar concentrations of the bile salt deoxycholate are shown to rescue the activity of an inactive mutant, E101A, in the K proton pathway of Rhodobacter sphaeroides cytochrome c oxidase. A crystal structure of the wild-type enzyme reveals, as predicted, deoxycholate bound with its carboxyl group at the entrance of the K path. Since cholate is a known potent inhibitor of bovine oxidase and is seen in a similar position in the bovine structure, the crystallographically defined, conserved steroid binding site could reveal a regulatory site for steroids or structurally related molecules that act on the essential K proton path.
A conserved steroid binding site in cytochrome C oxidase.,Qin L, Mills DA, Buhrow L, Hiser C, Ferguson-Miller S Biochemistry. 2008 Sep 23;47(38):9931-3. Epub 2008 Aug 30. PMID:18759498
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
↑ Qin L, Mills DA, Buhrow L, Hiser C, Ferguson-Miller S. A conserved steroid binding site in cytochrome C oxidase. Biochemistry. 2008 Sep 23;47(38):9931-3. Epub 2008 Aug 30. PMID:18759498 doi:10.1021/bi8013483