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The Role of Aromaticity, Hybridization, Electrostatics, and Covalency in Resonance-Assisted Hydrogen Bonds of Adenine–Thymine (AT) Base Pairs and Their Mimics

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 π 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 sp2 to sp3, 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 σ-electron system, with the covalency being responsible for shortening the hydrogen bonds in these dimers

ChemistryOpen, 2015, vol. 4, núm. 3, p. 318-327

Wiley

Author: Guillaumes Domènech, Laia
Simon i Rabasseda, Sílvia
Fonseca Guerra, Célia
Date: 2015 June
Abstract: 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 π 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 sp2 to sp3, 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 σ-electron system, with the covalency being responsible for shortening the hydrogen bonds in these dimers
Format: application/pdf
ISSN: 2191-1363
Document access: http://hdl.handle.net/10256/10829
Language: eng
Publisher: Wiley
Collection: Reproducció digital del document publicat a: http://dx.doi.org/10.1002/open.201402132
Articles publicats (D-Q)
Is part of: ChemistryOpen, 2015, vol. 4, núm. 3, p. 318-327
Rights: Attribution-NonCommercial-NoDerivs 3.0 Spain
Rights URI: http://creativecommons.org/licenses/by-nc-nd/3.0/es/
Subject: Resonance
Ressonància
Enllaços d’hidrogen
Hydrogen bonding
ADN
DNA
Funcional de densitat, Teoria del
Density functionals
Orbitals moleculars
Molecular orbitals
Aromaticitat (Química)
Aromaticity (Chemistry)
Title: The Role of Aromaticity, Hybridization, Electrostatics, and Covalency in Resonance-Assisted Hydrogen Bonds of Adenine–Thymine (AT) Base Pairs and Their Mimics
Type: info:eu-repo/semantics/article
Repository: DUGiDocs

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