title: Rescue of yeast defective in mitochondrial ATP synthase subunit 8 by a heterologous gene from Aspergillus nidulans.
abstract: Mitochondrial ATP synthase subunit 8 of the yeast Saccharomyces cerevisiae and of the filamentous fungus Aspergillus nidulans have the same length and similar structural motifs. However, the two proteins share only 50% identical residues, with the conserved residues being concentrated in the N- and C-terminal domains. We have investigated whether it is amino acid sequence or overall structural motifs that are required for subunit 8 function. PCR was used to construct a gene encoding A. nidulans subunit 8 fused to an N-terminal cleavable mitochondrial targeting sequence. Following expression in the nucleus of a yeast strain deficient in subunit 8, the chimaeric precursor targeted the subunit 8 protein back to the mitochondrion. The A. nidulans subunit 8 was found to be able to restore growth on non-fermentable substrate at 18 degrees C and 28 degrees C, but not at 36 degrees C. Given the sequence divergence between subunit 8 of A. nidulans and that of S. cerevisiae, this finding suggests that common structural motifs are important for subunit 8 function.
authors.affiliation: Department of Biochemistry, Monash University, Clayton, Victoria, Australia.
authors.forename: A F
authors.initials: AF
authors.lastname: Straffon
authors.forename: P
authors.initials: P
authors.lastname: Nagley
authors.forename: R J
authors.initials: RJ
authors.lastname: Devenish
mesh_terms: D000595:Amino Acid Sequence; D001233:Aspergillus nidulans / Q000201:enzymology* / Q000235:genetics; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers; D004926:Escherichia coli; D017353:Gene Deletion; D005800:Genes, Fungal; D046911:Macromolecular Substances; D008928:Mitochondria / Q000201:enzymology*; D010957:Plasmids; D016133:Polymerase Chain Reaction; D006180:Proton-Translocating ATPases / Q000096:biosynthesis / Q000235:genetics*; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D017386:Sequence Homology, Amino Acid
chemical_list: D017931:DNA Primers; D046911:Macromolecular Substances; D006180:Proton-Translocating ATPases