Nearly all major cellular processes are carried out by large molecular machines consisting of assemblies of interacting proteins. To understand how these machines work, researchers use the method of x-ray macromolecular crystallography to obtain high-resolution structural snapshots of proteins and their interactions. They apply this information to research projects in bioengineering, biomanufacturing, human health and drug development. SSRL provides novel facilities for this research, with high automation, accessible from scientists’ home institution, and with streamlined access. For example, during the COVID-pandemic, researchers used the SSRL macromolecular crystallography beam lines for 1) structural studies of SARS-CoV-2 proteins and binding partners, to understand the mechanisms of their interactions; 2) structural characterization of neutralizing antibodies and nanobodies with the SARS-CoV-2 Spike proteins, to aid in the development of vaccines and biologics; and 3) structural studies of SARS-CoV-2 proteins with various small molecules, inhibitors and lead drug compounds, to support small molecule drug discovery efforts. In addition to combating viral pathogens, biomedical researchers use crystallography during structure-based drug design efforts targeting antibiotic resistance, cancer, cardiovascular disease, neurodegeneration and other disorders.