The interest of our laboratory is to better understand the dynamic structure of proteins, biological membranes and nucleic acids and to relate dynamics to function. Light provides a relatively non-invasive probe whose power lies in its ability to examine intact, functional macromolecular assemblies. Fluorescence spectroscopy is of value for studies of protein dynamics on the pico- to nanosecond time scales. We utilize single photocounting methods to measure the decay times of tryptophan in proteins as a function of emission wavelength. The data is used to generate time-resolved emission spectra. Similar data is obtained in the sub picosecond time scale using the upconversion method. The latter experiments are done at the NIH in collaboration with Dr. Jay Knutson. Suitable procedures are used to determine whether the ultrafast spectral shifts are due to microheterogeneity or to dielectric relaxation of the protein matrix and the solvent.

The interest of our laboratory is to better understand the dynamic structure of proteins, biological membranes and nucleic acids and to relate dynamics to function. Light provides a relatively non-invasive probe whose power lies in its ability to examine intact, functional macromolecular assemblies. Fluorescence spectroscopy is of value for studies of protein dynamics on the pico- to nanosecond time scales. We utilize single photocounting methods to measure the decay times of tryptophan in proteins as a function of emission wavelength. The data is used to generate time-resolved emission spectra. Similar data is obtained in the sub picosecond time scale using the upconversion method. The latter experiments are done at the NIH in collaboration with Dr. Jay Knutson. Suitable procedures are used to determine whether the ultrafast spectral shifts are due to microheterogeneity or to dielectric relaxation of the protein matrix and the solvent.