The GxxxG motif of the transmembrane domain of subunit e is involved in the dimerization/oligomerization of the yeast ATP synthase complex in the mitochondrial membrane.
A conserved putative dimerization GxxxG motif located in the unique membrane-spanning segment of the ATP synthase subunit e was altered in yeast both by insertion of an alanine residue and by replacement of glycine by leucine residues. These alterations led to the loss of subunit g and the loss of dimeric and oligomeric forms of the yeast ATP synthase. Furthermore, as in null mutants devoid of either subunit e or subunit g, mitochondria displayed anomalous morphologies with onion-like structures. By taking advantage of the presence of the endogenous cysteine 28 residue in the wild-type subunit e, disulfide bond formation between subunits e in intact mitochondria was found to increase the stability of an oligomeric structure of the ATP synthase in digitonin extracts. The data show the involvement of the dimerization motif of subunit e in the formation of supramolecular structures of mitochondrial ATP synthases and are in favour of the existence in the inner mitochondrial membrane of associations of ATP synthases whose masses are higher than those of ATP synthase dimers.
Arselin
Geneviève
G
Institut de Biochimie et Génétique Cellulaires du CNRS, Université Victor Segalen, Bordeaux, France.
Giraud
Marie-France
MF
Dautant
Alain
A
Vaillier
Jacques
J
Brèthes
Daniel
D
Coulary-Salin
Bénédicte
B
Schaeffer
Jacques
J
Velours
Jean
J
D000595:Amino Acid Sequence; D001665:Binding Sites; D017124:Conserved Sequence; D019281:Dimerization; D007425:Intracellular Membranes / Q000201:enzymology / Q000648:ultrastructure; D007700:Kinetics; D046911:Macromolecular Substances; D008928:Mitochondria / Q000201:enzymology* / Q000648:ultrastructure; D025261:Mitochondrial Proton-Translocating ATPases / Q000737:chemistry* / Q000378:metabolism* / Q000648:ultrastructure; D008969:Molecular Sequence Data; D021122:Protein Subunits; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D046911:Macromolecular Substances; D021122:Protein Subunits; D025261:Mitochondrial Proton-Translocating ATPases