Tandon P, Gupta V D, Mehrotra C, Gupta D C
Department of Physics, University of Lucknow, India.
Indian J Biochem Biophys. 1992 Dec;29(6):449-57.
The Zimm and Bragg theory of the helix<-->coil transition has been modified to explain order<-->order transitions in polynucleotides, in particular B<-->Z<-->psi(-)<-->coil transitions in poly(dG-dC) and poly(dG-me5dC). Lambda anomalies in specific heat measurements around the transition point have also been explained by a further modification of the same theory. Theoretical results are found to be in good agreement with the experimental data. The nucleation parameter is consistent with the stabilization/destabilization of the ordered states (Z helix) under various environmental conditions, e.g. methylation of cytosine residue at C5 position or change in the cationic concentration of the solvent.
齐姆和布拉格的螺旋-线圈转变理论已被修正，以解释多核苷酸中的有序-有序转变，特别是聚（dG-dC）和聚（dG-me5dC）中的B-Z-ψ(-)-线圈转变。转变点附近比热测量中的λ异常也通过同一理论的进一步修正得到了解释。理论结果与实验数据吻合良好。成核参数与各种环境条件下有序状态（Z螺旋）的稳定/不稳定一致，例如C5位置胞嘧啶残基的甲基化或溶剂阳离子浓度的变化。
