Date of Completion

Spring 5-8-2011

Thesis Advisor(s)

Robert R. Birge

Department

Cell Biology

Disciplines

Cell Biology | Molecular Biology

Abstract

Bacteriorhodopsin, found in most halobacteria, is an integral protein that contains seven transmembrane alpha helices and an organic chromophore, all-trans retinal. Light energy is captured by the protein and results in a series of spectrally discrete intermediates that conclude with a proton being pumped across the membrane from the cytoplasmic side to the extracellular milieu. The most blue-shifted photo-intermediate, the M state, has been of interest for protein-based holographic memory storage devices. Bacteriorhodopsin mutants were prepared with either a 4-hydroxy retinal or 3,4-dihydro retinal analog: R82A, R82C, R82H, R82K, R82N and R82Q. The objective of this research was to investigate the effect of the combination of genetic and organic modification on the bacteriorhodopsin protein with respect to the formation and lifetime of the M state. Time-resolved UV-vis spectroscopy of the 4-hydroxy R82 analogs revealed an enhanced M state, potentially making these R82 analogs an effective candidate for device applications involving holographic memory.