Dr. Ebrey is studying light energy transduction in the purple membrane of Halobacterium halobium. A variety of physical techniques will be used to investigate its only pigment, bacteriorhodopsin (BR) and its photocycle intermediates. The purple membrane is a particularly simple biological light-energy transducer. A great deal is known about the structure of both BR and the purple membrane. A broad attack on the problem of how light causes the pumping of protons across the cell membrane is planned. The key to this problem is to understand the interrelationships between the structure of both the chromophore and the protein part of bacteriorhodopsin, the photochemistry that occurs when the chromophore absorbs a photon and the movement of protons across the cell membrane. The well-defined nature of the problem of relating proton pumping activity, the photochemistry of the purple membrane and the structure of BR make it an extremely important area of study in biology today.***//
