A comparison of DNA condensation in a solution containing the poly-l-lysine with the different number of monomers n = 2, 3, 5, 270, 325 was carried out in the presence of low molecular electrolyte 5 mM NaCl. It was shown that despite the identical results of DNA condensation induced by compounds (poly-L-lysine and its oligopeptides), the kinetic of DNA packaging and conformational changes prior to condensation depends on whether they belong to a long polycations or short oligomers. DNA secondary and tertiary structures were examined using Spectral methods (Spectrophotometry, Fluorescent Spectroscopy, Circular Dichroism), and with Dynamic Light Scattering, Low Gradient Viscometry, Flow Birefringence, and AFM. AFM images were obtained after DNA fixation from solutions on mica surface with Mg ions.
DNA condensation, poly-L-lysine, oligopeptides, kinetic of DNA packaging
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