title: Effects of torsional strain on thermal denaturation of DNA.
abstract: A class of simple statistical mechanical models for DNA melting, first proposed by Poland and Scheraga, has been demonstrated to exhibit a first or second order thermodynamic singularity, notwithstanding the intrinsic one-dimensional nature of the problem. In the present paper we consider the case of circular DNA and show that the inclusion of twist elastic energy in the Poland-Scheraga models leads either to suppression of the thermodynamic singularity or to a weak, third order singularity. Such behavior may also be present in linear DNA under mechanical influences that preclude the release of torsional strain.
authors.affiliation: Department of Physics and Astronomy, University of California at Los Angeles, Box 951547, Los Angeles, California 90095-1547, USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: Rudnick
authors.forename: Robijn
authors.initials: R
authors.lastname: Bruinsma