Dependence of polynucleotide helix–coil transition theory on the ring closure exponent

Abstract

Formulas are derived which relate the maximum slope of the helix‐coil transition in synthetic polynucleotides to the stacking free energy and to the exponent k in the expression for the probability of ring closure for polymer chains. The exact value of k has not yet been determined. By use of the derived formulas, it is then shown that estimates of the stacking free energy are sensitive enough to the value chosen for k, so that exact values of these energies must await a precise determination of k.