Accumulation of 14 alpha-methylergosta-8,24(28)-dien-3 beta,6 alpha-diol in 14 alpha-demethylation mutants of Candida albicans: genetic evidence for the involvement of 5-desaturase.
14 alpha-Demethylation mutants of the fungus Candida albicans have been shown to accumulate 14 alpha-methylergosta-8,24(28)-dien-3 beta,6 alpha-diol. A derivative from one of these mutants (KD4900) that does not form this 6 alpha-hydroxylated sterol but is still defective in 14 alpha-demethylation (KD4950) was obtained. Mutational restitution of 14 alpha-demethylation capacity to this derivative resulted in the formation of the 5,6-saturated sterol ergosta-7,22-dien-3 beta-ol as the major product, clearly indicating that 5-desaturase deficiency exists in this demethylation-proficient revertant (KD4952). This implies that its parent, KD4950, which has lost the ability to form the hydroxylated sterol, also is deficient in 5-desaturation. We infer from the results that 5-desaturase is responsible for the formation of the hydroxylated sterol. However, it is unclear whether the hydroxylation represents a genuine step of the normal 5-desaturation reaction.
Shimokawa
O
O
Department of Microbiology, School of Dentistry, Kyushu University, Fukuoka, Japan.
Kato
Y
Y
Kawano
K
K
Nakayama
H
H
D002176:Candida albicans / Q000235:genetics / Q000378:metabolism*; D002845:Chromatography / Q000379:methods; D003640:Dealkylation; D004875:Ergosterol / Q000031:analogs & derivatives* / Q000378:metabolism; D009154:Mutation; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D013057:Spectrum Analysis / Q000379:methods; D013261:Sterols / Q000378:metabolism*
D013261:Sterols; C059675:14-methylergosta-8,24(28)-dien-3,6-diol; D010088:Oxidoreductases; C039306:sterol delta-5 desaturase; D004875:Ergosterol