Biopolymers and cell. 1986. Volume 2. № 3. 124 - 129
S. A. Kozyavkin, S. M. Mirkin, B. R. Amirikyan
THE IONIC STRENGTH DEPENDENCE OF THE COOPERATIVITY FACTOR IN DNA MELTING
Summary
The melting temperatures for the d(AT)24-d(AT)24 stretch located inside the DNA helix or terminally have been determined in a wide range of the ionic strength values (0.01-1 M Na+). The values of cooperativity factor were calculated from the shifts in the melting temperature of the stretch due to its different boundary conditions. With a decrease of the sodium concentration from 1 to 0.01 M the cooperativity factor has dropped by three orders of magnitude, its change being less pronounced at high ionic strengths than at low ones.