The Regulation of the Albomycin and Desferrioxamine E Biosynthesis in Streptomyces globisporus bja209

We identified <i>Streptomyces globisporus</i> bja209 through a targeted screen of actinomycetes from natural habitats using an <i>E. coli</i> JW5503 ΔtolC DualRep2(c) reporter strain. This strain produced antibacterial compounds whose action depended on the growth medium. HPLC-MS and genomic analysis revealed two metabolites: albomycin δ2 (a translation inhibitor) and desferrioxamine E. The latter induced the SOS response. Desferrioxamine E exhibited a narrow spectrum of antagonistic activity against carbapenem-resistant <i>A. baumannii</i> and <i>C. michiganensis</i>, and its production was critically regulated by iron concentration. Notably, the structurally similar desferrioxamine B was inactive. Contrary to previous reports, pangenome analysis of published GenBank genomes revealed that albomycin BGC is restricted to specific <i>S. globisporus</i> strains and not present in other Streptomycetes phylogenetic clades. The C-1027 BGC was found in a large linear plasmid (165.5 kb) of the <i>S. globisporus</i> bja209 strain and also found exclusively on linear plasmids in some of the published <i>S. globisporus</i> genomes.