251. The molecular basis for the natural resistance of the cytochrome bc1 complex from strobilurin-producing basidiomycetes to center Qp inhibitors.
- Author
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Kraiczy P, Haase U, Gencic S, Flindt S, Anke T, Brandt U, and Von Jagow G
- Subjects
- Amino Acid Sequence, Basidiomycota genetics, Carrier Proteins antagonists & inhibitors, Carrier Proteins genetics, Carrier Proteins metabolism, Cloning, Molecular, Consensus Sequence, Cytochrome b Group genetics, DNA, Fungal genetics, DNA, Mitochondrial genetics, Electron Transport Complex III chemistry, Electron Transport Complex III genetics, Fatty Acids, Unsaturated biosynthesis, Fatty Acids, Unsaturated pharmacology, Genes, Fungal, Methacrylates, Mitochondria metabolism, Models, Molecular, Molecular Sequence Data, Oxidation-Reduction, Oxygen Consumption, Protein Folding, Restriction Mapping, Sequence Homology, Amino Acid, Strobilurins, Ubiquinone antagonists & inhibitors, Ubiquinone metabolism, Antifungal Agents biosynthesis, Basidiomycota metabolism, Electron Transport Complex III metabolism, Ubiquinone analogs & derivatives
- Abstract
Mitochondria from the strobilurin A producing basidiomycetes Strobilurus tenacellus and Mycena galopoda exhibit natural resistance to (E)-beta-methoxyacrylate inhibitors of the ubiquinol oxidation center(center Qp) of the cytochrome bc1 complex. Isolated cytochrome bc1 complex from S. tenacellus was found to be highly similar to that of Saccharomyces cerevisiae with respect to subunit composition, as well as spectral characteristics and midpoint potentials of the heme centers. To understand the molecular basis of natural resistance, we determined the exon/intron organization and deduced the sequences of cytochromes b from S. tenacellus, M. galopoda and a third basidiomycete, Mycena viridimarginata, which produces no strobilurin A. Comparative sequence analysis of two regions of cytochrome b known to contribute to the formation of center Qp suggested that the generally lower sensitivity of all three basidiomycetes was due to the replacement of a small amino acid residue in position 127 by isoleucine. For M. galopoda replacement of Gly143 by alanine and Gly153 by serine, for S. tenacellus replacement of a small residue in position 254 by glutamine and Asn261 by aspartate was found to be the likely causes for resistance to (E)-beta-methoxyacrylates. The latter exchange is also found in Schizosaccharomyces pombe, which we found also to be naturally resistant to (E)-beta-methoxyacrylates.
- Published
- 1996
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