The unusual reversion properties of a mitochondrial mutation in the structural gene of subunit I of cytochrome oxidase of Saccharomyces cerevisiae reveal a probable histidine ligand of the redox center.
We have analyzed a mutation in the mitochondrial gene oxi3 coding for subunit I of cytochrome-oxidase in the yeast Saccharomyces cerevisiae. This mutation replaces one of the seven invariant histidines of the polypeptide (position 378) by a tyrosine, and leads to a respiratory deficient phenotype. A total of 157 revertants, which have recovered the ability to grow on a respiratory substrate, have been selected from this mutant (tyrosine 378). The nature of the reversion has been analysed by a rapid screening procedure and 32 of the revertants have been sequenced. They are all true back-mutations reintroducing the histidine in position 378. This very exceptional situation suggests that this histidine is a ligand of the redox center of cytochrome oxidase.
Netter
P
P
Centre de Génétique Moléculaire, Laboratoire Propre du C.N.R.S. Associé à l'Université Pierre et Marie Curie, Gif sur Yvette, France.
Robineau
S
S
Sirand-Pugnet
P
P
Fauvarque
M O
MO
D000595:Amino Acid Sequence; D003576:Electron Transport Complex IV / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005800:Genes, Fungal; D006639:Histidine / Q000235:genetics / Q000378:metabolism*; D008024:Ligands; D008928:Mitochondria / Q000201:enzymology*; D008969:Molecular Sequence Data; D009154:Mutation; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D011487:Protein Conformation; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D016415:Sequence Alignment
D008024:Ligands; D006639:Histidine; D003576:Electron Transport Complex IV