Our research starts from the hypothesis that sequence and structural information combined with biophysical analysis can reveal the fundamental physical principles that underlie a wide range of biological phenomena. Our work includes theoretical research, biophysical measurements, the development of software tools, and specific applications to problems of biological importance. In the past few years, we have elucidated the structural and energetic origins of protein-protein, protein-nucleic acid, and protein-membrane interactions, developed methods for protein structure prediction, and detected novel structural and functional relationships between proteins based on their geometric similarity. We are currently focusing on two distinct areas: the molecular basis of cell-cell recognition, and the use of structural information to predict protein function on a genome-wide scale.