Conformational transitions and specific heat anomaly in poly(dG-dC) and its methylated analogue.
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.
Tandon
P
P
Department of Physics, University of Lucknow, India.
Gupta
V D
VD
Mehrotra
C
C
Gupta
D C
DC
D002151:Calorimetry; D006358:Hot Temperature; D007700:Kinetics; D008433:Mathematics; D009690:Nucleic Acid Conformation; D011089:Polydeoxyribonucleotides / Q000737:chemistry*; D013816:Thermodynamics
D011089:Polydeoxyribonucleotides; C019530:poly(dC-dG); C029988:poly(dG-m(5)dC).poly(dG-m(5)dC)