Similarities and differences in the influence of polycations and oligomers on DNA conformation and packaging

A comparison of DNA conformational changes in a solution containing the poly-l-lysine with the number of monomers z = 3, 5, 17, 20, 270, 325 and polyamines (spermine and spermidine) was carried out in 1 M and 5 mM NaCl solutions. It was shown that despite the identical results of DNA condensation induced by compounds, their influence on the DNA conformation prior to packaging depends on whether they belong to a long polycations or short oligomers. DNA secondary and tertiary structures were examined using Circular Dichroism, UV–vis Spectrophotometry, Dynamic Light Scattering, Low Gradient Viscometry, Flow Birefringence, and AFM. The phase diagrams for systems of DNA-polycations, DNA-oligomers, DNA-polyamines were drawn.