Molecular Biology and Assembly of Yeast Mitochondrial ATP Synthase

This work concerns the structure, function and assembly of the non-F1 proteins of the mitochondrial ATP synthase complex (mtATPase). A variety of in vitro and in vivo approaches based on molecular genetic manipulation has been used in our laboratory to study mtATPase in bakers’ yeast Saccharomvces cerevisiae. Here we review our recent advances concerning this enzyme complex including: 1) the dramatic enhancement of import of proteins into mitochondria by duplication of the N-terminal cleavable leader sequence; 2) the development of immunochemical procedures to study the assembly into mtATPase of subunits imported into isolated mitochondria; and 3) site-directed mutagenesis of an artificial nuclear gene encoding subunit 8. This molecular genetic manipulation of subunit 8 has demonstrated the role of its C-terminal positively-charged region in the assembly of subunit 8 into mtATPase. Further, the minimal effects on function of positive charges introduced into the hydrophobic domain of subunit 8 questions the assumption that this domain represents a transmembrane stem.