“Trojan horse” antibiotic albomycins are peptidyl nucleosides consisting of a highly modified 4′-thiofuranosyl cytosine moiety and a ferrichrome siderophore that are linked by a peptide bond via a serine residue. selleck chemicals While the latter component selleckchem serves to sequester Inhibitors,Modulators,Libraries iron from the environment, the seryl nucleoside portion is a potent inhibitor of bacterial seryl-tRNA synthetases, Inhibitors,Modulators,Libraries resulting in broad-spectrum antimicrobial activities of albomycin delta(2). The isolation of albomycins has revealed this biological activity is optimized only following Inhibitors,Modulators,Libraries two unusual cytosine modifications, N4-carbamoylation and N3-methylation. We identified a genetic locus (named abm) for albomycin production in Streptomyces sp. ATCC 700974.

Gene deletion and complementation experiments along with bioinformatic analysis suggested 18 genes are responsible for albomycin biosynthesis and resistance, allowing us to propose a potential biosynthetic pathway for installing the novel chemical features. The gene abmI, encoding a putative methyltransferase, was functionally assigned in Inhibitors,Modulators,Libraries vitro and shown to modify the N3 of a variety Inhibitors,Modulators,Libraries of cytosine-containing nucleosides and Inhibitors,Modulators,Libraries antibiotics such as blasticidin S. Furthermore, a Delta abmI mutant was shown to produce the descarbamoyl-desmethyl albomycin analogue, supporting that the N3-methylation occurs before the N4-carbamoylation in the biosynthesis of albomycin delta(2). The combined genetic information was utilized to identify an abm-related locus (named ctj) from the draft genome of Streptomyces sp.

C.

Cross-complementation Inhibitors,Modulators,Libraries experiments and in vitro studies Inhibitors,Modulators,Libraries with CtjF, the AbmI homologue, suggest the production of a similar 4′-thiofuranosyl cytosine in this organism. In total, the genetic and biochemical data provide a biosynthetic template for assembling siderophore-inhibitor conjugates and modifying Inhibitors,Modulators,Libraries the albomycin scaffold to generate new derivatives.
Elucidating mechanisms of natural organofluorine biosynthesis is essential for a basic understanding of fluorine biochemistry in living systems as well as for expanding biological methods for fluorine incorporation into small molecules of interest.

To meet this goal we have combined massively parallel sequencing technologies, genetic knockout, and in vitro biochemical approaches to investigate the fluoride response of the only known genetic host of an organofluorine-producing Inhibitors,Modulators,Libraries pathway, Streptomyces cattleya. Interestingly, selleckchem SCH66336 we have discovered that the major mode of S. cattleya’s resistance selleck chemical to the fluorinated toxin it produces, fluoroacetate, may be due to temporal control of production rather than the ability of the host’s metabolic machinery to discriminate between fluorinated and non-fluorinated molecules.