Researchers have determined the structure and mechanism of dehydrosqualene synthase (CrtM), an enzyme that performs the crucial first step in the formation of cholesterol and a key virulence factor in staph bacteria. The researchers already knew what CrtM looked like and its end product, but they didn’t know how the enzyme did its job. Uncovering the mechanism of action will enable scientists to design better inhibitors, and even tailor them to other targets.