The biosynthesis of ansatrienin (mycotrienin) has been studied in radioactive and stable isotope feeding experiments with Streptomyces collinus Tü 1892. The m-C7N unit of the ansa ring is efficiently and specifically derived from 3-amino-5-hydroxybenzoic acid; shikimic acid is not incorporated into this part of the molecule but does label the cyclohexanecarboyxlic acid moiety, providing all seven of its carbon atoms. Incorporation of methionine confirms origin of the methoxy group by transmethylation. The D-alanine moiety is derived directly from D-alanine rather than L-alanine. The terminal steps in the conversion of shikimic acid into cyclohexanecarboyxlic acid seem to be sequential reduction of 2,5-dihydrobenzoic acid and cyclohexene-1-carboxylic acid as evidenced by feeding experiments and the detection of a new ansatrienin containing a 1-cyclohexene instead of the cyclohexane moiety.
Feeding experiments with labelled precursors suggest that the 2-amino-3-hydroxycyclopent-2-enone moiety of the anticoccidial antibiotic, asukamycin, is formed by a novel intramolecular cyclization of 5-aminolevulinic acid.A number of antibiotics have been discovered in recent years which contain as a unique structural feature a 2-amino-3hydroxycyclopent-2-enone (1) moiety. These include in addition to asukamycin (2),1,2 the subject of this report, the related compounds manumycin3 and U-56,407,4 as well as reductiomycin,S moenomycin A,6 senacarcin A,7 virustomycin A,8 and bafilomycin.9 We report results which suggest a mode of biosynthesis of this novel structural unit.Experiments were carried out using cultures of Streptomyces nodosus subsp. usukuensis grown in 100 ml of medium (2% glucose, 2% soybean meal, 0.3% NaC1, pH adjusted to 7.0) in 500 ml indented Erlenmeyer flasks at 28 "C on a rotary shaker (300 r.p.m.). Precursors were fed 24 h after inoculation and 48 h later asukamycin (2) was extracted with ethyl acetate and purified by preparative layer chromatography (silica gel; benzene-acetone, 3 : 1). The purified (2) was quantitated by
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.