platensimycin

Platensimycin, a metabolite of Streptomyces platensis, is an antibiotic, which acts by blocking the enzymes β-ketoacyl-(acyl-carrier-protein (ACP)) synthase I/II (FabF/B).

==History== Platensimycin was first isolated from a strain of Streptomyces platensis by workers at Merck. Screens of 250,000 natural product extracts (83,000 strains in three growth conditions) led to the identification of a potent and selective small molecule from a strain of Streptomyces platensis recovered from a soil sample collected in South Africa. The identification process was carried out using a two-plate system in which control organisms were compared to cells expressing FabF antisense RNA. This method uses a combination of target-based whole-cell and biochemical assays, allowing compounds to be detected at concentrations that would be too low to detect using whole cell assays. The molecule they identified, platensimycin (C24H27NO7, relative molecular mass 441.47), comprises two distinct structural elements connected by an amide bond. The Merck Group showed that platensimycin has potent, broad-spectrum Gram-positive activity in vitro and exhibits no cross-resistance to other key antibiotic-resistant bacteria including Methicillin-resistant Staphylococcus aureus(MRSA), vancomycin-intermediate S. aureus, vancomycin-resistant Enterococci, and linezolid-resistant and macrolide-resistant pathogens.