ATP synthase of yeast mitochondria. Isolation of subunit j and disruption of the ATP18 gene.
The subunit composition of the mitochondrial ATP synthase from Saccharomyces cerevisiae was analyzed using blue native gel electrophoresis and high resolution SDS-polyacrylamide gel electrophoresis. We report here the identification of a novel subunit of molecular mass of 6,687 Da, termed subunit j (Su j). An open reading frame of 127 base pairs (ATP18), which encodes for Su j, was identified on chromosome XIII. Su j does not display sequence similarity to ATP synthase subunits from other organisms. Data base searches, however, identified a potential homolog from Schizosaccharomyces pombe with 51% identity to Su j of S. cerevisiae. Su j, a small protein of 59 amino acid residues, has the characteristics of an integral inner membrane protein with a single transmembrane segment. Deletion of the ATP18 gene encoding Su j led to a strain (Deltasu j) completely deficient in oligomycin-sensitive ATPase activity and unable to grow on nonfermentable carbon sources. The presence of Su j is required for the stable expression of subunits 6 and f of the F0 membrane sector. In the absence of Su j, spontaneously arising rho- cells were observed that lacked also ubiquinol-cytochrome c reductase and cytochrome c oxidase activities. We conclude that Su j is a novel and essential subunit of yeast ATP synthase.
Arnold
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I
Institut für Physiologische Chemie der Universität München, 80336 München, Germany.
Pfeiffer
K
K
Neupert
W
W
Stuart
R A
RA
Schägger
H
H
D000595:Amino Acid Sequence; D001483:Base Sequence; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D017353:Gene Deletion; D007425:Intracellular Membranes / Q000201:enzymology; D008928:Mitochondria / Q000201:enzymology*; D025261:Mitochondrial Proton-Translocating ATPases; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D006180:Proton-Translocating ATPases / Q000235:genetics* / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D012568:Schizosaccharomyces / Q000201:enzymology* / Q000235:genetics; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; D029701:Saccharomyces cerevisiae Proteins; C116839:ATP18 protein, S cerevisiae; D025261:Mitochondrial Proton-Translocating ATPases; D006180:Proton-Translocating ATPases