Subunit f of the yeast mitochondrial ATP synthase: topological and functional studies.
Modified versions of subunit f were produced by mutagenesis of the ATP17 gene of Saccharomyces cerevisiae. A version of subunit f devoid of the last 28 amino acid residues including the unique transmembranous domain complemented the oxidative phosphorylation of the null mutant. However, a two-fold decrease in the specific ATP synthase activity was measured and attributed to a decrease in the stability of the mutant ATP synthase complex as shown by the low oligomycin-sensitive ATPase activity at alkaline pH. The modification or not by nonpermeant maleimide reagents of cysteine residues introduced at the N and C termini of subunit f indicated a Nin-Cout orientation. From the C terminus of subunit f it was possible to cross-link subunit 4 (also called subunit b), which is another component of the F0 sector and which also displays a short hydrophilic segment exposed to the intermembrane space.
Roudeau
S
S
Institut de Biochimie et Génétique Cellulaires du CNRS, Université Victor Séalen, Bordeaux, France.
Spannagel
C
C
Vaillier
J
J
Arselin
G
G
Graves
P V
PV
Velours
J
J
D003001:Cloning, Molecular; D018388:Codon, Terminator; D003432:Cross-Linking Reagents; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D007425:Intracellular Membranes / Q000201:enzymology; D007700:Kinetics; D046911:Macromolecular Substances; D008928:Mitochondria / Q000201:enzymology*; D008970:Molecular Weight; D016297:Mutagenesis, Site-Directed; D009840:Oligomycins / Q000494:pharmacology; D006180:Proton-Translocating ATPases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology*
D018388:Codon, Terminator; D003432:Cross-Linking Reagents; D046911:Macromolecular Substances; D009840:Oligomycins; D011994:Recombinant Proteins; D006180:Proton-Translocating ATPases