Affinity capillary electrophoresis for the screening of novel antimicrobial targets.

The increasing number of multiantibiotic-resistant organisms, including methicillin-resistant Staphylococcus aureus (MRSA), requires the development of novel chemotherapies that are structurally distinct and exempt from current resistance mechanisms. Bioinformatics data mining of microbial genomes has revealed numerous previously unexploited essential open reading frames (ORFs) of unknown biochemical function. The potential of these proteins as screening targets is not readily apparent because most screening technologies rely on knowledge of biological function. To address this problem, the authors employed affinity capillary electrophoresis (ACE) to identify antimicrobial compounds that bound the novel target YihA. Screening a small-molecule library of 44,000 compounds initially identified 115 binders, of which 76% were confirmed. Furthermore, the ACE assay distinguished diverse compounds that possessed drug-like properties and antimicrobial activity against drug-resistant clinical isolates. These data validate ACE as a valuable tool for the fast, efficient detection of specific binding molecules that possess biological activity.