Like many other Hopkins biophysicists, I work on protein structural biology problems.  Proteins and some RNA molecules are life's chemical engines.  In order to perform their specific and complex biological functions, proteins must achieve a well-ordered three-dimensional structure.  However, a protein is synthesized in an unfolded form based on the gene that encodes it, and the three-dimensional form of the protein forms spontaneously out of this unfolded form.  Many computational biophysicists like myself are interested in "structure prediction," that is, predicting this folded structure of the protein based on its sequence without having to determine its structure experimentally.  Much information can be derived from a protein's three-dimensional structure, but there is much more to a cell, even more to an organism, than the structures of all of its proteins.  Many proteins must alter their function, and hence their structures, in response to some environmental change; this is the problem of regulation.  In addition, proper function of cells and organisms requires cells from different parts of the organism to act synchronously, and proteins within cells to communicate with each other through a process known as signal transduction.  These signaling pathways are involved in such processes as cell division regulation, optical and olfactory response, and hormone response.  Improper functioning of these pathways can lead to disease; for example, the malfunction of cell cycle control is the primary cause of many cancers.  Signal transduction is just regulation on a higher level, not involving just the response of a single protein to environmental conditions, but often a whole network of proteins.  On the biomolecular level, I refer to this as the problem of "structural sensitivity."  For example, how does a drug alter the structure of a biochemically important protein in order to inhibit that protein and treat a disease? My work focuses on the extension of an existing structure prediction algorithm known as Rosetta to simulate how protein structures respond to binding a small molecule or another protein.