4-Methylzymosterone and Other Intermediates of Sterol Biosynthesis from Yeast Mutants Engineered in the ERG27 Gene Encoding 3-Ketosteroid Reductase

• Published in: Lipids 2016-09, Vol.51 (9), p.1103-1113
• Main Authors: Ferrante, Terenzio, Barge, Alessandro, Taramino, Silvia, Oliaro-Bosso, Simonetta, Balliano, Gianni
• Format: Article
• Language: English
• Subjects: 3‐Ketosteroid reductase; 4‐Methylfecosterone; 4‐Methylzymosterone; Biomedical and Life Sciences; Biosynthesis; Chemical reduction; Engineered yeast strains; Genetic Engineering; Life Sciences; Lipidology; Lipids; Medical Biochemistry; Medicinal Chemistry; Methods; Microbial Genetics and Genomics; Mutation; Neurochemistry; Nutrition; Oxidoreductases - genetics; Oxidoreductases - metabolism; Physiology; Post‐squalene sterol biosynthesis; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - growth & development; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins - genetics; Saccharomyces cerevisiae Proteins - metabolism; Sterols - biosynthesis; Yeasts
• ISSN: 0024-4201; 1558-9307
• DOI: 10.1007/s11745-016-4173-6

Studies in the post-squalene section of sterol biosynthesis may be hampered by the poor availability of authentic standards. The present study used different yeast strains engineered in 3-ketosteroid reductase (Erg27p) to obtain radioactive and non-radioactive intermediates of sterol biosynthesis hardly or not available commercially. Non-radioactive 3-keto 4-monomethyl sterones were purified from non-saponifiable lipids extracted from cells bearing point-mutated 3-ketosteroid reductase. Two strategies were adopted to prepare the radioactive compounds: (1) incubation of cell homogenates of an ERG27 -deletant strain with radioactive lanosterol, (2) incubation of growing cells of a strain expressing point-mutated 3-ketosteroid reductase with radioactive acetate. Chemical reduction of both radioactive and non-radioactive 3-keto sterones gave the physiological 3-β OH sterols, as well as the non-physiological 3-α OH isomers. This combined biological and chemical preparation procedure provided otherwise unavailable or hardly available 4-mono-methyl intermediates of sterol biosynthesis, paving the way for research into their roles in physiological and pathological conditions.