The gene coding for the yeast oligomycin sensitivity-conferring protein.

Abstract

The gene coding for the yeast Saccharomyces cerevisiae mitochondrial oligomycin sensitivity-conferring protein (OSCP) has been sequenced, and the gene products have been characterized. The OSCP is subunit 5 of the mitochondrial ATP synthase, a multimeric protein complex. As such, the gene coding for the yeast OSCP is referred to here as the ATP5 gene. From the predicted primary sequence, the calculated molecular weight of the immature yeast OSCP is 22,813 and the amino acid sequence is 35% identical and 65% homologous to bovine OSCP. A null mutant has been constructed. This mutant strain is unable to grow on glycerol medium, has no detectable oligomycin-sensitive ATPase activity, and has no detectable immune reactive proteins with the corresponding molecular weight of the OSCP (using antibodies reactive to the yeast OSCP). The transcription products of the yeast gene have been characterized. There is a single major transcript from the ATP5 gene of 1.05 kilobases. The level of the transcription product is increased from 3-5-fold after growth in galactose medium as compared to cells grown in glucose medium. The transcriptional initiation sites were determined to occur at +68(G) and +69(T) at comparable frequency and were not dependent on the growth medium. These results suggest that transcription of the ATP5 gene is catabolite-repressed.