期刊
CHEMISTRYOPEN
卷 4, 期 3, 页码 318-327出版社
WILEY-V C H VERLAG GMBH
DOI: 10.1002/open.201402132
关键词
aromaticity; density functional calculations; DNA base pairs; molecular orbital (MO) theory; nucleotides; resonance-assisted hydrogen bonding
资金
- Ministry of Science and Innovation, Spain (MICINN)
- European Fund for Regional Development (FEDER) [CTQ 2011 23441, UNGI08-4E-003, UNGI10-4E-801]
- MICINN [BES-2009-028463]
- Generalitat de Catalunya [SGR528]
- Xarxa de Referencia en Quimica Terica i Computacional
- National Research School Combination-Catalysis
- Netherlands Organization for Scientific Research (NWO-CW)
- Netherlands Organization for Scientific Research (NWO-EW)
Hydrogen bonds play a crucial role in many biochemical processes and in supramolecular chemistry. In this study, we show quantum chemically that neither aromaticity nor other forms of assistance are responsible for the enhanced stability of the hydrogen bonds in adenine-thymine (AT) DNA base pairs. This follows from extensive bonding analyses of AT and smaller analogs thereof, based on dispersion-corrected density functional theory (DFT). Removing the aromatic rings of either A or T has no effect on the Watson-Crick bond strength. Only when the smaller mimics become saturated, that is, when the hydrogen-bond acceptor and donor groups go from sp(2) to sp(3), does the stability of the resulting model complexes suddenly drop. Bonding analyses based on quantitative Kohn-Sham molecular orbital theory and corresponding energy decomposition analyses (EDA) show that the stronger hydrogen bonds in the unsaturated model complexes and in AT stem from stronger electrostatic interactions as well as enhanced donor-acceptor interactions in the sigma-electron system, with the covalency being responsible for shortening the hydrogen bonds in these dimers.
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