Heterologous Expression of the Formicamycin Biosynthetic Gene Cluster Unveils Glycosylated Fasamycin Congeners

Formicamycins and their biosynthetic intermediates thefasamycinsare polyketide antibiotics produced by Streptomyces formicae KY5 from a pathway encoded by the for biosyntheticgene cluster. In this work the ability of Streptomyces coelicolor M1146 and the ability of Saccharopolyspora erythraea & UDelta;ery to heterologously express the for biosynthetic gene cluster were assessed. This led tothe identification of eight new glycosylated fasamycins modified atdifferent phenolic groups with either a monosaccharide (glucose, galactose,or glucuronic acid) or a disaccharide comprised of a proximal hexose(either glucose or galactose), with a terminal pentose (arabinose)moiety. In contrast to the respective aglycones, minimal inhibitoryscreening assays showed these glycosylated congeners lacked antibacterialactivity.