Biopolym. Cell. 1986; 2(3):124-129.
Structure and Function of Biopolymers
The ionic strength dependence of the cooperativity factor in DNA melting
1Kozyavkin S. A., 1Mirkin S. M., 1Amirikyan B. R.
  1. Institute of Molecular Genetics, Academy of Sciences of the USSR
    Moscow, USSR


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.


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