TY - JOUR

T1 - Noncanonical Stacking Geometries of Nucleobases as a Preferred Target for Solar Radiation

AU - Ramazanov, R.R.

AU - Maksimov, D.A.

AU - Kononov, A.I.

PY - 2015

Y1 - 2015

N2 - Direct DNA absorption of UVB photons in a spectral range of 290-320 nm of terrestrial solar radiation is responsible for formation of cyclobutane pyrimidine dimers causing skin cancer. Formation of UVB-induced lesions is not random, and conformational features of their hot spots remain poorly understood. We calculated the electronic excitation spectra of thymine, cytosine, and adenine stacked dimers with ab initio methods in a wide range of conformations derived from PDB database and molecular dynamics trajectory of thymine-containing oligomer. The stacked dimers with reduced inter-base distances in curved, hairpin-like, and highly distorted DNA and RNA structures exhibit excitonic transitions red-shifted up to 0.6 eV compared to the B-form of stacked bases, which makes them the preferred target for terrestrial solar radiation. These results might have important implications for predicting the hot spots of UVB-induced lesions in nucleic acids.

AB - Direct DNA absorption of UVB photons in a spectral range of 290-320 nm of terrestrial solar radiation is responsible for formation of cyclobutane pyrimidine dimers causing skin cancer. Formation of UVB-induced lesions is not random, and conformational features of their hot spots remain poorly understood. We calculated the electronic excitation spectra of thymine, cytosine, and adenine stacked dimers with ab initio methods in a wide range of conformations derived from PDB database and molecular dynamics trajectory of thymine-containing oligomer. The stacked dimers with reduced inter-base distances in curved, hairpin-like, and highly distorted DNA and RNA structures exhibit excitonic transitions red-shifted up to 0.6 eV compared to the B-form of stacked bases, which makes them the preferred target for terrestrial solar radiation. These results might have important implications for predicting the hot spots of UVB-induced lesions in nucleic acids.

U2 - 10.1021/jacs.5b05140

DO - 10.1021/jacs.5b05140

M3 - Article

VL - 137

SP - 11656

EP - 11665

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

SN - 0002-7863

IS - 36

ER -