Abstract: A system for identifying novel antimicrobial agents is disclosed that includes the steps of attaching a &bgr;-lactamase inhibitor protein target to a solid support, exposing the &bgr;-lactamase inhibitor protein target to a &bgr;-lactamase inhibitor protein and an analyte, and detecting the effect of the analyte on the binding of the &bgr;-lactamase protein to its protein target, wherein a decrease in binding between the &bgr;-lactamase protein target and the &bgr;-lactamase inhibitor protein indicates that the analyte affects the interaction between &bgr;-lactamase inhibitor protein and its protein target.

Abstract: An composition, method and system for identifying novel antimicrobial agents including the steps of, displaying a &bgr;-lactamase inhibitor protein on a virus, contacting the virus with a &bgr;-lactamase binding protein target, selecting for the virus that has a higher affinity for the target and testing the &bgr;-lactamase inhibitor protein for antimicrobial activity, is disclosed. The invention also includes a nucleic acid encoding a fusion protein comprising a &bgr;-lactamase inhibitor protein and an affinity carrier and the protein expressed therefrom. Mutant &bgr;-lactamase inhibitor proteins may be produced, characterized, isolated and expressed in prokaryotic cells and used as antimicrobial agents.