Localization of lipid binding domain(s) on subunit II of beef heart cytochrome c oxidase.

Photoactivatable arylazido phospholipids (Bisson, R., and Montecucco, C. (1981) Biochem. J. 193, 757-763) have been used to study the arrangement in the membrane of beef heart cytochrome c oxidase subunit II. Fragmentation of the photocross-linked polypeptide showed that sequence 20-98, which contains two long stretches of uncharged amino acid residues (Steffens, G. J., and Buse, G. (1979) Hoppe-Seyler's Z. Physiol. Chem. 360, 613-619), is in contact with lipids. Edman degradation of the labeled peptide indicated that His 26, Thr 27 and Met 29 are involved in the interaction with the polar head region of the bilayer. These data have been used to propose a scheme for the folding of subunit II in the mitochondrial membrane.