The modification of the conserved GXXXG motif of the membrane-spanning segment of subunit g destabilizes the supramolecular species of yeast ATP synthase.

TitleThe modification of the conserved GXXXG motif of the membrane-spanning segment of subunit g destabilizes the supramolecular species of yeast ATP synthase.
Publication TypeJournal Article
Year of Publication2005
AuthorsBustos, DM, Velours, J
JournalJ Biol Chem
Volume280
Issue32
Pagination29004-10
Date Published2005 Aug 12
ISSN0021-9258
KeywordsAdenosine Triphosphate, Amino Acid Motifs, Amino Acid Sequence, Blotting, Western, Cell Membrane, Conserved Sequence, Cross-Linking Reagents, Cysteine, Digitonin, Dimerization, Disulfides, Microscopy, Electron, Transmission, Mitochondria, Mitochondrial Proton-Translocating ATPases, Models, Molecular, Molecular Sequence Data, Mutagenesis, Site-Directed, Oxygen, Phenotype, Protein Binding, Protein Conformation, Protein Structure, Tertiary, Proton-Translocating ATPases, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Sequence Homology, Amino Acid
Abstract

The supernumerary subunit g is found in all mitochondrial ATP synthases. Most of the conserved amino acid residues are present in the membrane C-terminal part of the protein that contains a dimerization motif GXXXG. In yeast, alteration of this motif leads to the loss of subunit g and of supramolecular structures of the ATP synthase with concomitant appearance of anomalous mitochondrial morphologies. Disulfide bond formation involving an engineered cysteine in position 109 of subunit g and the endogenous cysteine 28 of subunit e promoted g + g, e + g, and e + e adducts, thus revealing the proximity in the mitochondrial membrane of several subunits e and g. Disulfide bond formation between two subunits g in mitochondria increased the stability of an oligomeric structure of the ATP synthase in digitonin extracts. These data suggest the participation of the dimerization motif of subunit g in the formation of supramolecular structures and is in favor of the existence of ATP synthase associations, in the inner mitochondrial membrane, whose masses are higher than those of ATP synthase dimers.

DOI10.1074/jbc.M502140200
Alternate JournalJ. Biol. Chem.
Citation Key10.1074/jbc.M502140200
PubMed ID15970598