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A cooperative self‐consistent microscopic theory of thermally induced melting of a repeat sequence DNA polymer
Author(s) -
Chen Y. Z.,
Prohofsky E. W.
Publication year - 1993
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360330304
Subject(s) - premelting , base pair , melting temperature , chemistry , sequence (biology) , polymer , base (topology) , thermodynamics , phonon , dna , chemical physics , melting point , statistical physics , physics , condensed matter physics , materials science , mathematical analysis , biochemistry , mathematics , organic chemistry , composite material
We attempt to extend the modified self‐consistent phonon theory to describe thermal fluctuational base‐pair opening of repeat sequence DNA polymers in the helix–coil transition region as well as in the premelting region. A microscopic base‐pair open state is introduced and the effect of this open state is taken into account self‐consistently in a mean field system that models the DNA polymer. Our analysis indicates the structure of this open state changes with temperature in such a manner that on average a base pair opens and unstacks with its neighbors more completely as temperature increases. We apply this theory to a homopolymer—poly(dG) · poly(dC) to evaluate the base‐pair opening probability in a temperature range from 273 to 366.5 K. At 366.5 K the system undergoes cooperative melting. Our calculated base‐pair opening probabilities are in general agreement with several experimental estimates at room temperature. The calculated probabilities show typical melting curve behavior at temperatures close to the observed melting temperature. The cooperative modified self‐consistent phonon approximation approach becomes a viable microscopic theory of melting. © 1993 John Wiley & Sons, Inc.