EXAMINATION OF CONFORMATIONAL-CHANGES IN PROTEINS BY LOW-TEMPERATURE TRYPTOPHAN FLUORESCENCE AND PHOSPHORESCENCE SPECTROSCOPY

The conformational changes in some single tryptophan proteins were stu died by tryptophan fluorescence and phosphorescence spectroscopy at 77 degrees K. Both common experimental and approximation parameters were used. The experimental spectra were approximated by theoretical curve s obtained by resolution of the spectra into two independent series of vibrations. The tryptophan tow-temperature luminescence parameters ar e determined by the chromophore environment. They were found to depend on the accessibility of the chromophore for solvent molecules. Howeve r, the main factor is specific chromophore-environment interaction.