Log-normal component analysis of fluorescence spectra of prodan and acrylodan bound to proteins

Steady-state fluorescence spectra of prodan and acrylodan covalently bound to cystein residue of Lys-Cys-Phe tripeptide in solvents of different polar ity were analyzed. It was shown that the shape of spectral bands is well de scribed by a log-normal function. Linear relations between three shape-dete rmining parameters of the log-normal function (namely, the positions,of spe ctral maximum and two half-maximum amplitudes) were revealed and evaluated for both fluorophores. This finding enabled us to present the shape of spec tral bands of these fluorophores in any environment as analytical log-norma l function depending on only two parameters, the maximum position and the p eak amplitude. The empirical uniparametric log-normal curve was used for th e analysis of composite fluorescence spectra of prodan bound to bovine seru m albumin and acrylodan covalently attached to actin or subfragment 1 of my osin.