Absolute configuration of the hydroxyfarnesylethyl group of haem A, determined by X-ray structural analysis of bovine heart cytochrome c oxidase using methods applicable at 2.8 Å resolution

Abstract

The absolute configuration of haem A, the prosthetic group of cytochrome c oxidase, was determined to be S by analysis of the bond angles surrounding the chiral centre of haem A after refinement with X-PLOR starting from respective initial structures with R and S configurations under absolute configuration constraints at 1.8 Å resolution. The same result was obtained by refinement at 1.8 Å resolution without the absolute configuration constraints. Both of these methods were applicable down to a resolution of about 2.8 Å. The constrained refinement converges more quickly than the unconstrained refinement. © 2005 International Union of Crystallography - all rights reserved.