DNA is a fascinating biopolymer that controls many cellular functions. The structure of this exceedingly long-chain molecule, including its shape and state of stress, strongly influences major biological functions including gene transcription, replication and repair. Our lab develops theoretical models to explore how DNA bends and twists in response to bound protein and in forming DNA supercoils and loops. In addition, we study how DNA is packed into viruses and then dynamically ejected during host infection. Through collaborations with the Andricioaei Lab (Chemistry, UC Irvine), we have also developed novel, multi-scale models that combine atomistic and continuum representations to predict large and dynamic conformational changes of DNA structures due to protein/enzyme activities.