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Electron‐transfer restoration by vitamin K 3 in a complex III‐deficient mutant of S. cerevisiae and sequence of the corresponding cytochrome b mutation
Author(s) -
Brivet-Chevillotte Paule,
di Rago Jean-Paul
Publication year - 1989
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(89)81050-6
Subject(s) - mutant , cytochrome c oxidase , cytochrome b , coenzyme q – cytochrome c reductase , menadione , cytochrome , cytochrome c1 , biology , cytochrome c , biochemistry , antimycin a , microbiology and biotechnology , mitochondrial dna , mitochondrion , gene , enzyme
The yeast box‐mutant W7 exhibits deficiencies in cytochrome b and in nuclear coded complex III subunits, a phenotype observed previously in a patient with mitochondrial myopathy. DNA sequence analysis of mutant W7 revealed a single base transition in the cytochrome b gene; the mutated residue Gly 131 is perfectly conserved in all known cytochromes b and belongs to the Q 0 domain. Mutant W7 provides a model system for evaluating the action of therapeutic agents, such as vitamin K 3 which restored NADH‐oxidase activity in the mutant as well as in the antimycin‐inhibited wild type. However, with the mutant, a greater quantity of menadione was necessary due to a decrease in other complex activities, and a much lower electron‐flow fraction passed through cytochrome oxidase.