“…Our results imply that the search for protein structures involved in this activity should focus on COI and COIl, and that the more than ten years of speculation about a role of COUI in proton pumping (Casey et al, 1980;Prochaska et al, 1981;Wikstrom and Casey, 1985;Capitanio et al, 1990;Prochaska and Wilson, 1990; for reviews, see Azzi et al, 1984;Brunori et al, 1987;Prochaska and Fink, 1987;Chan and Li, 1990) should come to an end. COIII has a distinct role in the assembly of the functional oxidase (for other assembly factors needed at earlier stages of oxidase biosynthesis, see Nobrega et al, 1990;Tzagoloff et al, 1990;Steinrucke et al, 1991).…”