Before revision: In mechanical models of DNA, twist-bend coupling is a cross interaction term originating from the asymmetry between major and minor grooves.
After revision: By combining analytical results and simulations of various coarse-grained models we investigate the minimal energy shape of DNA minicircles which are torsionally constrained by an imposed over or undertwist. We show that twist-bend coupling is a cross interaction term originating from the asymmetry between major and minor grooves.