Solitary excitations in B-Z DNA transition: a theoretical and numerical study.

The molecular mechanism of B-Z DNA transition remains elusive since the elucidation of the left-handed Z-DNA structure using atomic resolution crystallographic study. Numerous proposals for the molecular mechanism have been advanced, but none has provided a satisfactory explanation for the process. A nonlinear DNA model is proposed which enables one to derive various hypothesized molecular mechanisms, namely the Harvey model, Zang and Olson model, and the stretched intermediate model, by imposing certain constraints and conditions on the model. These constraints raise the need to reevaluate experimental investigations on B-Z DNA transition.