Electronic Structure Change in DNA Caused by Base Pair Motions and Its Effect on Charge Transfer in DNA Chains

Abstract

One important aspect of carrier transfer in DNA is its coupling with atomic motions. The collective motion of the base pairs can either improve the charge transfer by enhancing the π stacking between the bases, or trap the carriers due to strong coupling. By utilizing a pseudo-helical base pair stack model, we systematically studied the electronic structure and its dependence to geometry changes that represent the important DNA motions, including the translation, the twist and the torsion of the base pairs. Our calculations reveal that the above motions may significantly change the electron structure and affect their transport properties. In order to improve the transport of carriers in DNA so that it can become a prospective material in future electronics, it is necessary to make large changes to the atomic structure. Our calculations of the electronic structure under large geometry variation, including large base pair stacking deformation and the insertion of phenyl rings in the bases, can provide good guidelines for such structural modifications of DNA.

Construction of a DNA‐Based Supramolecular Nanosheet That Emits Bluish‐White Light from Charge‐Transfer Excited States of the Nucleobases

“…In particular, the stacked bases in the stretched DNA of the nanosheet can be expected to have a geometry different from that of regular B‐DNA. Voityuk and Liu et al . have shown by calculations that the electronic coupling changes when the geometries of stacked bases are changed by twisting, shifting, and sliding, and that CT efficiency is significantly affected by π‐stacked structures of bases.…”

“…[6,10,11] In particular,t he stacked bases in the stretched DNA of the nanosheet can be expectedt oh ave ag eometry different from that of regular B-DNA. Voityuk [25] and Liu et al [26] have shown by calculations that the electronic couplingc hanges when the geometries of stacked bases are changed by twisting, shifting, and sliding, and that CT efficiency is significantly affected by pstacked structures of bases.Is uggest that the nucleobases in the supramolecular nanosheet probably exist in geometries that favor generation of CT states. Furthermore, the increasing intensity relative to salmons perm DNA was likely due to suppression of nonradiative paths in the nanosheet.…”