π -π orbital resonance in twisting duplex DNA: Dynamical phyllotaxis and electronic structure effects

Abstract

The presence of synchronized, collective twist motions of the Watson-Crick base pairs in DNA duplexes (helicoidal standing waves) can efficiently enhance the pi-pi orbital overlapping between nonconsecutive base pairs via a long-range, phonon-correlated tunneling effect. The resulting structural patterns are described within the framework of dynamical phyllotaxis, providing a realistic treatment which takes into account both the intrinsic three-dimensional, helicoidal geometry of DNA, and the coupling between the electronic degrees of freedom and double-helix DNA molecular dynamics at low frequencies. The main features of the resulting electronic band structures are discussed for several resonance frequencies of interest, highlighting the possible biophysical implications of the obtained results.