LRET-Based HTS of a Small-Compound Library for Inhibitors of Bacterial RNA Polymerase

Resistance mechanisms against whole classes of antibiotics are currently developing faster than research generates new structurally different biologically active agents. The demand for new antimicrobial drugs has not been matched by the speed of discovery. The interface between σ and core of bacterial RNA polymerase offers an attractive target for drug discovery, and we have previously described the development of a very robust high-throughput assay for this target based on luminescence resonance energy transfer. Here we describe a semiautomated screen of a commercially available library (Chembridge, San Diego, CA) that led to the identification of four small molecules, two of which have activity in preventing in vitro transcription and growth of Escherichia coli.