Analysis of revertants from respiratory deficient mutants within the centerNof cytochromebinSaccharomyces cerevisiae
| Autor: | Anne-Marie Colson, Hideto Miyoshi, Jean-Yves Coppée, J P di Rago, D Marc, N Tokutake |
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| Rok vydání: | 1994 |
| Předmět: |
Molecular Sequence Data
Mutant Biophysics Antimycin A Saccharomyces cerevisiae Mitochondrial cytochrome A Biology DNA Mitochondrial Polymerase Chain Reaction Biochemistry Antimycin resistance Non-native reversion chemistry.chemical_compound Multienzyme Complexes Structural Biology Aspartic acid Genetics NADH NADPH Oxidoreductases Respiratory deficiency mutation Codon DNA Fungal Molecular Biology Heme Alanine Methionine Base Sequence Cytochrome b Wild type Chromosome Mapping Drug Resistance Microbial Sequence Analysis DNA Cell Biology Cytochrome b Group chemistry Coenzyme Q – cytochrome c reductase Mutation |
| Zdroj: | FEBS Letters. 339:1-6 |
| ISSN: | 0014-5793 |
| DOI: | 10.1016/0014-5793(94)80373-0 |
| Popis: | Four modified cytochrome b's carrying mononucleotide substitutions affecting center N residues were analysed. The mutant carrying a G33D change does not incorporate heme into the apocytochrome b and fails to grow on non-fermentable carbon sources. Out of 85 genetically independent revertants derived from this mutant, 82 were true back-mutants restoring the wild type sequence (D33G). The remaining three replaced the aspartic acid by an alanine (D33A) indicating that small size residues are best tolerated at this position which is consistent with the perfect conservation of the G33 during evolution. This glycine may be of crucial importance for helix packing around the hemes. The replacement of methionine at position 221 by lysine (M221K.) produced a non-functional cytochrome b [(1993) J. Biol. Chem. 268,15626-15632]. Non-native revertants replacing the lysine 221 by glutamic acid (K221E) or glutamine (K221Q) expressed a selective resistance to antimycin and antimycin derivatives having a modified dilactone ring moiety. Cytochrome b residues in 33 and in 221 seemed to contribute to the quinone reduction (QN) site of the cytochrome bc1 complex. Possible intramolecular interactions between the N-tenninal region and the loop connecting helices IV and V of cytochrome b are proposed. |
| Databáze: | OpenAIRE |
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