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