Electron migration in DNA matrix: an electron transfer reaction

Abstract

This paper brings an active and provocative area of current research. It describes the investigation of electron transfer (ET) chemistry in general and ET reactions results in DNA in particular. Two DNA intercalating molecules were used: Ethidium Bromide as the donor (D) and Methyl-Viologen as the acceptor (A), the former intercalated between DNA bases and the latter in its surface. Using the Perrin model and fluorescence quenching measurements the distance of electron migration, herein considered to be the linear spacing between donor and acceptor molecule along the DNA molecule, was obtained. A value of 22.6 (± 1.1) angstroms for the distance and a number of 6.6 base pairs between donor and acceptor were found. In current literature the values found were 26 angstroms and almost 8 base pairs. DNA electron transfer is considered to be mediated by through-space interactions between the p-electron-containing base pairs.

Covalent Anion of the Canonical Adenine−Thymine Base Pair. Ab Initio Study

“…The unique double-helical ladder structure of base-pair rings in DNA creates a compact stack of π-electrons associated with the base pairs, promoting the question as to whether DNA could possibly serve as an electrical conduit. The issue of DNA conductivity related to the electron-transfer processes has been a focus of several recent investigations. − The ability of DNA to conduct an electron current can be impaired by formation of stable anions by the DNA bases and base pairs. The changes in acidity or basidity, which result from loss or uptake of the electron from or by a base in a base pair of DNA, can stop the migration of electrons in the direction of the DNA helix via the stacked bases .…”