Molecular analysis of revertants from a respiratory-deficient mutant affecting the center o domain of cytochrome b in Saccharomyces cerevisiae.
In bc complexes, cytochrome b plays a major role in electron transfer and in proton translocation across the membrane. Several inhibitor-resistant and respiratory-deficient mutants have already been used to study the structure-function relationships of this integral membrane protein. We describe here the selection and the molecular analysis of revertants from a thermo-sensitive mit-mutant of known nucleotide changes. Among 80 independent pseudo-wild type revertants screened by DNA-labelled oligonucleotide hybridization, 33 have been sequenced. Eight suppressor mutations, affecting a region critical for both the function and the binding of center o inhibitors (end of helix C) were identified. Two of them were found to be more resistant to myxothiazol.
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Laboratoire de Génétique Microbienne, Université Catholique de Louvain la Neuve, Louvain, Belgium.
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Coppee
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Colson
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D000595:Amino Acid Sequence; D001483:Base Sequence; D003573:Cytochrome b Group / Q000235:genetics*; D004271:DNA, Fungal / Q000235:genetics; D005800:Genes, Fungal; D008969:Molecular Sequence Data; D009154:Mutation; D009693:Nucleic Acid Hybridization; D011487:Protein Conformation; D012333:RNA, Messenger / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics
D003573:Cytochrome b Group; D004271:DNA, Fungal; D012333:RNA, Messenger