DEFECT-MEDIATED HYDROGEN-BOND MELTING IN B-DNA POLYMERS

This paper explores the melting temperatures of the hydrogen bonds that hold together the two strands of DNA. We choose as samples both homopolymers and copolymers of DNA. First, we investigate the melting temperatures of hydrogen bonds throughout the polymer via a mean-field approach. Then a defect is introduced by cutting the hydrogen bonds in one unit cell at room temperature. We study the propagation of this defect to neighboring cells with rise in temperature. The calculation is a modified self-consistent phonon approach. The agreement between the calculated melting temperatures and observed melting temperatures is excellent for defected melting. The defected melting is an approximation to initiation-site melting. © 1990 The American Physical Society.