Variety of Scaling Laws for DNA Thermal Denaturation

Abstract

We discuss possible mechanisms that may impact the order of the transition between denaturated and bound DNA states and lead to changes in the scaling laws that govern conformational properties of DNA strands. To this end, we re-consider the Poland-Scheraga model and apply a polymer field theory approach to calculate entropic exponents associated with the denaturated loop distribution. We discuss in particular variants of this transition that may occur due to the properties of the solution and may affect the self-and mutual interaction of both single and double strands. We find that the effects studied significantly influence the strength of the first order transition. This is manifest in particular by the changes in the scaling laws that govern DNA loop and strand distribution. As a quantitative measure of these changes we present the values of corresponding scaling exponents. For the d = 4 − ε case we get corresponding ε 4 expansions and evaluate the perturbation theory expansions at space dimension d = 3 by means of resummation technique.