Chemical structure determines biological function. As chemists, the members of the Gibney lab take a constructive approach to studying the relationships between chemical structure and biological dysfunction that leads to human disease. Our current interests lie in the area of heme proteins involved in cardiovascular disease and zinc finger transcription factor proteins implicated in human cancer. Our investigative tools center on the measurement of the fundamental thermodynamics of metal-peptide and metal-protein binding equilibria. These data provide critical insight into the basic engineering principles of proteins containing heme or zinc.