THE CU-A SITE OF CYTOCHROME-C-OXIDASE

The recent exciting developments concerning the structure and function of the Cu-A site in cytochrome c oxidase (COX) and nitrous oxide redu ctase are reviewed. The XRD structures of a mitochondrial and a bacter ial COX have been reported in 1995, In COX, the Cu-A centre is located in subunit II and is involved in electron transfer from a cytochrome c donor to the oxygen binding centre of the protein. The structural st udies on the enzyme have revealed the coordination geometries of the m any metal centres of COX, including the Cu-A site. A combination of sp ectroscopic and mutagenesis studies on the Cu-A centre led to the corr ect prediction of the structure of this unique copper centre. The cons truction of a Cu-A site in type 1 blue copper proteins is briefly disc ussed.