EFFECT OF MOLECULAR-DYNAMICS ON PHOTOINDU CED ELECTRON-TRANSFER IN EOSIN-MYOGLOBIN COMPLEX

The temperature dependence of the rate constant of photoinduced electr on transfer in the modified eosin-myoglobin complex by monitoring of t he phosphorescence quenching of eosin is measured. The values of elect ron transfer rate constants are equal 10(2) divided by 10(3) s(-1) in the temperature region 150-200 K. The kinetics of relaxation of the ma ximum of the time-resolved phosphorescence spectra of eosin on apomiog lobin is measured in the same temperature range. The solvation relaxat ion of the time-resolved phosphorescence spectra is nonexponential. Th e characteristic times of the solvation relaxation are given 10(-2)div ided by 10(-4) s(-1), that correlate with the time of electron transfe r in this system. It was observed the <<acceleration>> of the relaxati on rate of the time-resolved phosphorescence spectra of eosin in metmy oglobin due to nonequilibrium photoinduced electron transfer. The role of the matrix dynamics in photoinduced electron transfer in proteins is discussed.