I am interested in combining concepts from protein science and bioinorganic chemistry to develop peptide ligands for non-biological metal centers with unique and selective catalytic activity. Polypeptides represent a modular ligand framework that enables both rational design of structure over significant length scales and randomized diversity. This talk will present recent work with dirhodium metallopeptides, taking advantage of the unique coordination chemistry, catalytic activity, and biological interactions of dirhodium centers. Our catalyst design approach involves both design and screening components. High-throughput peptide screening has allowed us to identify new catalysts for enantioselective and diastereoselective reactivity and to discover new coordination environments for successful asymmetric catalysis. In addition, we have developed designed catalysts that incorporate molecular recognition as a means of achieving site-specific modification of complex polyfunctional substrates such as proteins.