FLUORESCENCE LINE NARROWING APPLIED TO THE STUDY OF PROTEINS

Fluorescence line narrowing is a high resolution spectroscopic techniq ue that uses low temperature and laser excitation to optically select specific subpopulations from the inhomogeneously broadened absorption band of the sample. When applied to the study of fluorescent groups in proteins one can obtain vibronically resolved spectra, which can be a nalyzed to give information on spectral line shapes, vibrational energ ies of both the ground and excited state molecule, and the inhomogeneo us distribution function of the electronic transitions. These paramete rs reveal information about the chromophoric prosthetic group and the protein matrix and are functions of geometric strains and local electr ic fields imposed by the protein. Examples of the use of fluorescence line narrowing are discussed in investigations of heme proteins, photo synthetic systems and tryptophan-containing proteins. (C) 1998 Elsevie r Science B.V. All rights reserved.