DNA T4 Condensation in Water-Alcohol Media

The compaction of high-molecular weight DNA T4 in a water-alcohol medium has been studied by AFM. The AFM images of compact globules formed by DNA molecules in water-alcohol media have been obtained . It has been found that at 40-50% alcohol concentrations, the DNA molecules form partially compacted formations in which particular coils of the macromolecule are twisted to form toroidal structures. Using the procedure of the recovery of the true geometric parameters of the object by the AFM profile. we have showed that the globule contains one DNA molecule. The model of DNA packing during the compaction has been proposed .