Role of gamma-subunit N- and C-termini in assembly of the mitochondrial ATP synthase in yeast.

The gamma-subunit is required for the assembly of ATP synthases and plays a crucial role in their catalytic activity. We stepwise shortened the N-terminus and the C-terminus of the gamma-subunit in the mitochondrial ATP synthase of yeast and investigated the relevance of these segments in the assembly of the enzyme and in the growth of the cells. We found that a deletion of 9 residues at the N-terminus or 20 residues at the C-terminus still allowed efficient import of the subunit into mitochondria; however, the assembly of both monomeric and dimeric holoenzymes was partially impaired.

Biogenesis of yeast dicarboxylate carrier: the carrier signature facilitates translocation across the mitochondrial outer membrane.

A family of related carrier proteins mediates the exchange of metabolites across the mitochondrial inner membrane. The carrier signature Px[D/E]xx[K/R] is a highly conserved sequence motif in all members of this family. To determine its function in the biogenesis of carrier proteins, we used the dicarboxylate carrier (DIC) of yeast as a model protein.