Many biological processes are carried out by multi-component macromolecular assemblies. The assembly and dynamics of these molecular machines is central to structural and cell biology, and has posed tremendous challenges owing to their unusual complexity. The research in our laboratory combines the power of X-ray crystallography and electron cryo-microscopy to understand the structure and dynamics of large molecular assemblies from viruses and pathogenic bacteria that cause diseases ranging from pneumonia, meningitis and shigellosis to mucocutaneous lesions, encephalitis and several forms of cancer. We aim to understand lifecycles of these pathogeic microorganisms at atomic detail in order to find better ways for prevention, treatment and cure.