The Lacy laboratory is focused on mechanisms of bacterial toxin function. Pathogenic bacteria have evolved a diverse array of mechanisms for delivering toxins and other virulence factors into the interior of host cells. Studying the molecular structures of these virulence factors alone and in complex with host receptors, membranes, and inhibitors can lend insight into how these delivery processes occur and how these processes can be exploited or prevented. Current research in the Lacy laboratory is primarily focused on the structure and function of large clostridial cytotoxins, including the three toxins responsible for symptoms in Clostridioides difficile infection. Structural biology is combined with cellular, tissue, and animal models of intoxication and infection to understand the toxin-host interaction at the molecular level. In addition, we aim to identify new toxin inhibitors using both rational design and high-throughput screening approaches. Elucidating the molecular structures and functions of these virulence factors alone and in complex with host receptors and inhibitors will reveal fundamental mechanisms in bacterial pathogenesis and provide a framework for new therapeutic and prevention strategies.