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Conformational dependence of the electronic coupling in guanine–tryptophan complexes: A DFT study
Author(s) -
Butchosa C.,
Simon S.,
Voityuk A. A.
Publication year - 2011
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.23077
Subject(s) - chemistry , guanine , tryptophan , electron transfer , acceptor , dna , electronic structure , aromatic amino acids , coupling (piping) , crystallography , density functional theory , computational chemistry , stereochemistry , amino acid , photochemistry , materials science , biochemistry , nucleotide , physics , metallurgy , gene , condensed matter physics
Radical cation states (electron holes) generated in DNA lead to mutagenic effects. In DNA–protein complexes, the holes can migrate from DNA to aromatic amino acid residues preventing the formation of the oxidative lesions. The efficiency of hole transfer (HT) may significantly depend on the arrangement of redox sites. This dependence is mainly determined by sensitivity of the electronic coupling of donor and acceptor to structural changes. Based on DFT calculations of a number of guanine–tryptophan (G–Trp) complexes, we explore the conformational dependence of HT electronic coupling in this dyad. Stacked and T‐shaped structures are considered. The electronic coupling in the system is shown to be responsive to the mutual arrangement of G and Trp. Although in most cases the probability of HT in T‐shaped conformations is predicted to be lower than in π stacks, several T‐type structures are found where HT should be very efficient. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem 112:1838–1843, 2012