Effect of Anderson Localization on Auger Destruction of DNA

Abstract

The effect of Anderson localization in DNA on the Auger destruction by the Coulombic explosion at ionized radiation has been theoretically discussed in the present work. The theory of Auger destruction of DNA has been modified taking into account the localized and delocalized electron states in DNA owing to the correlated disorder in a sequence of nucleotides. According to the modified theoretical model of Auger destruction, the dominant ratio of delocalized states to localized states in exon compared to intron results in stronger radiation resistance of exons to ionized irradiation causing the Auger-cascade process than the radiation resistance of introns.One of the interesting and important applications of the localization theory developed for one-dimensional systems [1][2][3][4] is related to conductivity of DNA molecules [4][5][6]. The electronic structure of DNA represents a very interesting problem by itself. Surely the mobility of electrons along the sequence effects DNA's functional behavior (information transferring, enzyme-DNA interactions, etc.) and its structural-sequential integrity. The charge migration is believed to be important for the radiation damage repair [7]. The recent study has shown that single-base mutations on DNA molecules may lead to significant changes in conductance [8]. Since most of the mutations in DNA are successfully healed, they assumed the existence of charge transport through delocalized states, responsible for the transfer of information at much longer distances.DNA macromolecule is considered to be a long sequence of discrete site potentials-basic nucleotides. The electron transport along this sequence occurs due to hopping between the neighboring nucleotides. This property justifies the application of the tight binding model. An uncorrelated sequence of nucleotides localizes all quantum electron states, as occurs in one-dimensional white-noise potential, making impossible the charge transfer at distances longer than the localization length. Studies of long-range correlation in nucleotide structure resulted in proclamation that DNA was aperiodic crystal with long-range correlation [9]. In the work [4-6] in the framework of the two-channel tight-binding model it was shown how the information coded in a sequence of nucleotides may affect the localization length (therefore, the resistivity) of a given segment of a DNA molecule. The principal results of these work are that for the most of the energies the localization length inside the exon (the coding regions of DNA) region exceeds by order of magnitude the localization length inside the intron region (the noncoding regions of DNA). This confirms the fact that very different kinds of information are coded in these regions. The presence of extended states in the spectrum of exons regions strongly supports a hypothesis that the information about DNA repair processes transfers in a damaged DNA along a nucleotide sequence due to electrical mechanisms. Since proteins detect the damaged region in a sequence by virtue of transport ...