2 MODES OF AGGREGATION OF ARTIFICIAL H1-DNA COMPLEXES DEPENDING ON THE RATE OF DECREASE OF IONIC-STRENGTH

The properties of H1-DNA artificial complexes, formed at different rates of decrease of NaCl concentration from 0.9 to 0.15 M, were investigated. It was found that two distinct processes, both depending on the rate of the concentration decrease, lead to the formation of aggregates differing in: the ability to form sediments, the distribution of sedimentation constants, the initial turbidity and its changes during trypsin and DNAase I digestion, and the H1 DNA ratio in the sediments. The accessibility of DNA in the complexes to DNAase I and the properties of nonaccessible DNA fragments led us to the conclusion that, at the H1 DNA ratio equal 0.2, the H1 molecules are clustered along the DNA chain independently of the rate of complex formation. © 1979.