Dr. Hubbell has studied the relationship between the
molecular structure of
protein and the conformational changes that control its function. Of particular interest are
membrane proteins that behave as "molecular switches", i.e., proteins whose structures are switched to an active state by a physical or chemical signals. An example is light-activated
rhodopsin, the visual pigment in photoreceptor cells of the
retina. The goal is to elucidate the structure of rhodopsin, the mechanism of the molecular switch, and regulation of this switch by associated proteins,
transducin and
arrestin. Dr. Hubbell's research also includes structure and function relationships in water-soluble proteins such as the lens protein,
a-crystallin, and the
retinoid carrying proteins which transport
vitamin A throughout photoreceptor cells. Dr. Hubbell's laboratory developed
site-directed spin labeling (SDSL), a technique for the exploration of protein structure and dynamics. By changing the genetic code, a specific attachment point in the protein is created for a nitroxide spin label probe. Analysis of the
electron paramagnetic resonance (EPR) spectrum of the spin label provides information about the local environment in the protein. With a sufficiently large set of labeled proteins, global information on structure is obtained, and most importantly, changes in the structure during function can be followed in real time. ==Education and training==