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

We identified Streptomyces globisporus bja209 through a targeted screen of actinomycetes from natural habitats using an E. coli 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 A. baumannii and C. michiganensis, 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 S. globisporus 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 S. globisporus bja209 strain and also found exclusively on linear plasmids in some of the published S. globisporus genomes.