THE SUBUNIT-F OF MITOCHONDRIAL YEAST ATP SYNTHASE - CHARACTERIZATION OF THE PROTEIN AND DISRUPTION OF THE STRUCTURAL GENE ATP17

The subunit f of the yeast F(1)F(0)ATP synthase has been isolated from the purified enzyme. Amino acid composition, protein and peptide sequ encing were performed. The data are in agreement with the sequence of the predicted product of the gene D9381.21 identified on the Saccharom yces cerevisiae chromosome IV. A 303-bp open reading frame encoding a 101-amino acid polypeptide is described. The deduced amino acid sequen ce from the ATP17 gene is 6 amino acids longer than the mature protein , which displays a molecular mass of 10567 Da. The protein is basic wi th a short hydrophobic segment located in the C-terminal part of the s ubunit. Subunit f remained associated with other F-0 subunits upon sod ium bromide treatment of the whole enzyme. A null mutant was construct ed. The disrupted strain was unable to grow on glycerol medium and the mutation was recessive; rho(-) cells arose spontaneously. The null mu tant mitochondria were devoid of oligomycin-sensitive ATPase, but stil l contained an active F-1, while the subunits f,6 and 8 were absent.