Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: KEGG:D02011 (FAD)
 5,530 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Phytopathogenic Cercospora species produce cercosporin, a photoactivated perylenequinone toxin that belongs to a family of photosensitizers which absorb light energy and produce extremely cytotoxic, reactive oxygen species. In this work, we used Saccharomyces cerevisiae as a model system for the identification and cloning of genes whose products mediate cercosporin detoxification. Two genesexpressed in high-copy number vectors conferred cercosporin resistance to an otherwise sensitive strain. One gene codes for Snq2p, a well-characterized multidrug, ABC-type, efflux protein. The other, designated CPD1 (Cercosporin Photosensitizer Detoxification), encodes a novel protein with significant similarity to the FAD-dependent pyridine nucleotide reductases. We showed that over-expression of either of these proteins can also mediate resistance to other singlet oxygen-generating compounds. The involvement of Snq2p and Cpd1p in photosensitizer detoxification reinforces previous observations which suggested that singlet oxygen acts on membrane lipids and that cellular resistance to cercosporin is mediated by a mechanism involving toxin efflux and/or toxin reduction.
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PMID:A novel putative reductase (Cpd1p) and the multidrug exporter Snq2p are involved in resistance to cercosporin and other singlet oxygen-generating photosensitizers in Saccharomyces cerevisiae. 1140 74

Cercosporin is a non-host-selective, photoactivated polyketide toxin produced by many phytopathogenic Cercospora species, which plays a crucial role during pathogenesis on host plants. Upon illumination, cercosporin converts oxygen molecules to toxic superoxide and singlet oxygen that damage various cellular components and induce lipid peroxidation and electrolyte leakage. Three genes (CTB5, CTB6 and CTB7) encoding putative FAD/FMN- or NADPH-dependent oxidoreductases in the cercosporin toxin biosynthetic pathway of C. nicotianae were functionally analysed. Replacement of each gene via double recombination was utilized to create null mutant strains that were completely impaired in cercosporin production as a consequence of specific interruption at the CTB5, CTB6 or CTB7 locus. Expression of CTB1, CTB5, CTB6, CTB7 and CTB8 was drastically reduced or nearly abolished when CTB5, CTB6 or CTB7 was disrupted. Production of cercosporin was revived when a functional gene cassette was introduced into the respective mutants. All ctb5, ctb6 and ctb7 null mutants retained wild-type levels of resistance against toxicity of cercosporin or singlet-oxygen-generating compounds, indicating that none of the genes plays a role in self-protection.
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PMID:Functional characterization of three genes encoding putative oxidoreductases required for cercosporin toxin biosynthesis in the fungus Cercospora nicotianae. 1766 Apr 42