Study of DNA internal dynamics by quasi-elastic light scattering

摘要

We have studied the large-scale internal fluctuations in DNA coils by using quasi-elastic light-scattering spectroscopy. We have measured the angular dependence of the first cumulant of the scattered-light autocorrelation function. Within the q(3) domain of this dependence, we observed the transition from the asymptotic behavior predicted for good solvents to the asymptotic behavior predicted for Theta conditions. This allowed us to determine the screening length of volume interactions in DNA chains. Analysis of the autocorrelation functions by a regularization procedure allowed us to reconstruct the mode composition of the scattered light and to determine the relaxation time of the fluctuations in the coil size. (C) 1997 Optical Society of America.