A mutation in cytochrome oxidase subunit 2 restores respiration of the mutant pet ts1402.
The yeast PET1402/OXA1 gene encoding a 44.8-kDa protein is required for mitochondrial biogenesis. Substitution of Leu240 to serine in the protein results in an accumulation of the precursor form of the mitochondrially encoded subunit 2 of cytochrome oxidase (Cox2) and temperature-sensitive respiration. This temperature sensitivity can be suppressed by a mutation in the cox2 gene changing Ala189 of the Cox2 protein to proline. In the cox2-ts1402 double mutant respiration is restored without removal of the Cox2 pre-sequence. The suppression suggests an interaction of the Pet1402 protein with the cytochrome oxidase complex. Antibodies raised against the predicted C-terminus and the tagged N-terminus of the Pet1402 protein reacted with a 37-kDa polypeptide. This protein, present in the mitochondrial fraction, is localized within the inner membrane. The difference in size can be explained by the removal of the predicted mitochondrial-targeting sequence from the Pet1402 protein. The mitochondrial localization of the protein points to a direct interaction with the cytochrome oxidase complex.
Meyer
W
W
Institut für Allgemeine Botanik, Universität Hamburg, Ohnhorststrasse 18, D-22609 Hamburg, Germany.
Bauer
M
M
Pratje
E
E
D000595:Amino Acid Sequence; D019069:Cell Respiration / Q000502:physiology; D002874:Chromosome Mapping; D003576:Electron Transport Complex IV / Q000737:chemistry / Q000235:genetics*; D005800:Genes, Fungal; D007425:Intracellular Membranes / Q000378:metabolism; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000235:genetics*; D010641:Phenotype; D017354:Point Mutation; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D013347:Subcellular Fractions / Q000378:metabolism; D013489:Suppression, Genetic; D013696:Temperature
D010446:Peptide Fragments; D003576:Electron Transport Complex IV