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

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.