[Study of the conformational and intradynamic changes of phage lambda DNA molecules by laser correlation spectroscopy].

Conformational changes of lambda phage DNA macromolecules were investigated by dynamic light scattering (DLS) method. It was shown that the persistence length of B-form DNA in some conditions could could decline to approximately 12 nm. When studying the internal motions in the linear form of phage DNA macromolecule, a deviation was observed of the experimental angular dependence of the first cumulant gamma from theoretical predictions for the gamma in Rouse-Zimm model including hydrodynamic interactions. This deviation appeared in the region qRg >> 1, where Rg is gyration radius and q is momentum vector. The first cumulant deviation to higher frequencies is observed only for B-form DNA. Experimental behaviour of the first cumulant gamma for the A-form DNA coincides with the theoretical one in the Rouse-Zimm model.