Acquisition of a Phase-Lifetime Spectrofluorometer

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Trytophan and tyrosine are natural fluorophores and components of proteins. These biological chromophores are fluorescent, i.e., when photo excited they emit light which is characteristic of their chemical and physical environment. Fluorescence is an important analytical technique because of its extreme sensitivity and specificity. The time scale of the fluorescence phenomenon can make the technique a very effective probe of the surroundings of the fluorophore. The requested spectrofluorometer is a state-of-the-art instrument which provides spectral differentiation of fluorophores in a mixture on the basis of difference in fluorescence lifetimes. In the case of a protein molecule, the true emission profile of the tyrosine and tryptophan residues which contribute to the total fluorescence of the protein can be identified and monitored. The spectrofluorometer can also offer information on the molecular size, conformation, and interactions of fluorophores in a protein molecule. With these measurements, the dynamic chemical and physical nature of the fluorophores can be deduced. The biological research projects which require the use of the spectrofluorometer include: 1. The conformation of a metabolic enzyme, ornithine transcarbamoylase, under the influence of a variety of ligands will be analyzed. The goal is to probe the possible metabolic regulation of this enzyme. One of the most challenging problems in biochemistry today is the study of metabolic regulation. 2.The characterization of chromophore-based biopolymers using fluorescence techniques will be conducted to provide insight into how groups are assembled and communicate electronically along a polymer backbone. This study will aid the elucidation of the structure of biological polymer composite and the design of new materials for optical and electronic processing. 4. The molecular mechanism of the retinal based proteins, rhododpsin and bacteriorhodopsin, will be investigated for the understanding of phototransduction in membranes. 5. The development of skeletal muscle tissue in the vertebrate embryo is a complex multistep process which is not yet well understood. The sensitivity of the spectrofluorometer will be exploited to dissect out the signal transduction cascade within the myoblast membrane for the understanding of cell differentiation of muscle.