title: F0 part of the ATP synthase from Escherichia coli. Influence of subunits a, and b, on the structure of subunit c.
abstract: Four different sets of proteoliposomes were prepared from F0, subunit c, a complex of subunits a and c (ac complex) and an ac complex supplemented with subunit b. Only liposomes containing intact F0 or all subunits of F0 were active in proton translocation and F1 binding [Schneider, E. and Altendorf, K. (1985) EMBO J. 4, 515-518]. The conformation of subunit c in the different preparations was analyzed by labelling the proteoliposomes with the hydrophobic photoactivatable reagent 3-(trifluoromethyl)-3-(m-[125I]iodophenyl)diazirine ([125I]TID). Subsequent isolation and Edman degradation of this polypeptide revealed distinct radioactive labelling patterns over the entire amino acid sequence. In the F0 complex and in the ac complex subunit c retains a labelling pattern which is related to that found in TID-labelled membrane vesicles of Escherichia coli [Hoppe et al. (1984) Biochemistry 23, 5610-5616]. In the absence of subunit a, considerably more and different amino acid residues of subunit c are modified. The labelling data are discussed in relation to structural aspects of F0 and functional properties of proteoliposomes reconstituted with F0 or individual subunits.
mesh_terms: D001389:Azirines / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology*; D008081:Liposomes; D046911:Macromolecular Substances; D011485:Protein Binding; D011510:Proteolipids; D006180:Proton-Translocating ATPases / Q000378:metabolism*
chemical_list: D001389:Azirines; D008081:Liposomes; D046911:Macromolecular Substances; D011510:Proteolipids; C020485:proteoliposomes; C033174:3-(trifluoromethyl)-3-(3-iodophenyl)diazirine; D006180:Proton-Translocating ATPases