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3DTU: Catalytic Core Subunits (I and II) of Cytochrome C Oxidase From Rhodobacter Sphaeroides Complexed With Deoxycholic Acid
Biochemistry (2008) 47 p.9931-9933
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.
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