Biosynthetic origin of butyrolactol A, an antifungal polyketide produced by a marine-derived Streptomyces

• Enjuro Harunari,
• Hisayuki Komaki and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2017, 13, 441–450, doi:10.3762/bjoc.13.47

• , Kisarazu, Chiba 292-0818, Japan 10.3762/bjoc.13.47 Abstract Butyrolactol A is an antifungal polyketide of Streptomyces bearing an uncommon tert-butyl starter unit and a polyol system in which eight hydroxy/acyloxy carbons are contiguously connected. Except for its congener butyrolactol B, there exist no

• structurally related natural products to date. In this study, inspired by our previous genomic analysis, incorporation of 13C- and 2H-labeled precursors into butyrolactol A was investigated. Based on the labeling pattern and sequencing analytical data, we confirmed that the tert-butyl group is derived from

• valine and its C-methylation with methionine and the polyol carbons are derived from a glycolysis intermediate, possibly hydroxymalonyl-ACP. Keywords: biosynthesis; butyrolactol; contiguous polyol; hydroxymalonyl-ACP; polyketide; Streptomyces; tert-butyl; Introduction Actinomycetes produce structurally