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Isolation and Biosynthesis of an Azoxyalkene Compound Produced by a Multiple Gene Disruptant of Streptomyces rochei
Author(s) -
Kunitake Hirofumi,
Hiramatsu Takahiro,
Kinashi Haruyasu,
Arakawa Kenji
Publication year - 2015
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/cbic.201500393
Subject(s) - biosynthesis , moiety , mutant , biochemistry , streptomyces , gene , serine , stereochemistry , gene cluster , biology , polyketide , chemistry , genetics , bacteria , enzyme
Streptomyces rochei 7434AN4 predominantly produces lankacidin and lankamycin under normal culture conditions, thus suggesting that other biosynthetic gene clusters for secondary metabolites are silent. To identify the silent metabolites of 7434AN4, we constructed mutant KA57 with multiple disruptions of the transcriptional repressor srrB and the biosynthesis genes for both antibiotics. KA57 accumulated a compound (KA57A) with a strong UV absorption at 235 nm, not detected in the parent strain or other mutants. Various spectroscopic analyses revealed that KA57A is an azoxyalkene compound with the molecular formula C 10 H 20 N 2 O 3 and with the R configuration at C‐2. Biosynthesis of KA57A was also studied by feeding with labeled acetates, amino acids, and 1‐hexylamine. The hexenyl moiety (C1′–C6′) was derived from fatty acid, whereas the 3‐aminobutan‐1,2‐diol moiety (C1–C4) was derived from C‐2 of acetate (C1) and serine (C2–C4). Incorporation of [1,1‐ 2 H 2 ]‐1‐hexylamine indicated that C1′–C2′ dehydrogenation occurs as the final step of biosynthesis.