An inhomogeneous helicoidal nearest-neighbor model with continuous degrees of
freedom is shown to predict the same DNA melting properties as traditional
long-range Ising models, for free DNA molecules in solution, as well as
superhelically stressed DNA with a fixed linking number constraint. Without
loss of accuracy, the continuous degrees of freedom can be discretized using a
minimal number of discretization points, yielding an effective transfer matrix
model of modest dimension (d=36). The resulting algorithms to compute DNA
melting profiles are both simple and efficient.Comment: v3: Matlab toolbox included with source file; article unchanged, 12
pages, 11 figures, RevTe