The antibiotic daptomycin is produced by the Gram-positive bacterium Streptomyces roseosporus and is the first in a new class of investigational drugs called lipopeptides that is being developed by Cubist for the treatment of serious and life-threatening infections caused by Gram-positive pathogens. The goal of this phase I application is to develop a system that will allow the rapid manipulation of the daptomycin biosynthetic gene cluster. These tools would then be used in phase II of the application to elucidate the structure-activity realtionships (SAR) of daptomycin and use this information to create derivatives of daptomycin with increased potency against vancomycin resistant pathogens.