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The Formation of DNA Photodamage: The Role of Exciton Localization
Author(s) -
Rössle Shaila,
Friedrichs Jana,
Frank Irmgard
Publication year - 2010
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201000081
Subject(s) - thymine , pyrimidine dimer , cyclobutane , chemistry , exciton , dna , photochemistry , molecular orbital , oligonucleotide , nucleobase , pyrimidine , reactivity (psychology) , atomic orbital , chemical physics , computational chemistry , molecule , stereochemistry , dna damage , physics , ring (chemistry) , electron , biochemistry , quantum mechanics , organic chemistry , medicine , alternative medicine , pathology
The electronic structure during the formation of a cyclobutane pyrimidine dimer (CPD) between two thymine bases is investigated using semi‐empirical and first‐principles approaches. The dimerization of two isolated thymine bases is found to have no barrier or a very small barrier in agreement with previous studies suggesting low photostability of DNA. The well‐known high photostability of DNA can only be explained taking other factors into account. We investigate the role of the exciton location in the particular environment. Different model systems, from isolated thymine bases to an oligonucleotide in aqueous solution, are discussed. Analysis of the frontier orbitals allows one to understand the connection between the location of the exciton, the relative orientation of the thymine bases, and the observed reactivity.