Lone-pair–pi interactions: analysis of the physical origin and biolological implications

Investor logo

Warning

This publication doesn't include Faculty of Education. It includes Faculty of Science. Official publication website can be found on muni.cz.
Authors

NOVOTNÝ Jan BAZZI Sophia MAREK Radek KOZELKA Jiří

Year of publication 2016
Type Article in Periodical
Magazine / Source Physical Chemistry Chemical Physics
MU Faculty or unit

Faculty of Science

Citation
Web DOI: 10.1039/C6CP01524G
Doi http://dx.doi.org/10.1039/C6CP01524G
Field Physical chemistry and theoretical chemistry
Keywords lone-pair-pi interaction; anion-pi; DFT; energy decomposition analysis
Description Lone-pair-pi (lp-pi) interactions have been suggested to stabilize DNA and protein structures, and to participate in the formation of DNA-protein complexes. To elucidate their physical origin, we have carried out a theoretical multi-approach analysis of two biologically relevant model systems, the water-indole and water-uracil complexes, which we compared with the structurally similar chloride-tetracyanobenzene (TCB) complex previously shown to contain a strong charge-transfer (CT) binding component. We demonstrate that the CT component in lp-pi interactions between water and indole/uracil is significantly smaller than that stabilizing the Cl-TCB reference system. The strong lp(Cl-)-pi(TCB)* orbital interaction is characterized by a small energy gap and an efficient lp-pi* overlap. In contrast, in lp-pi interactions between water and indole or uracil, the corresponding energy gap is larger and the overlap less efficient. As a result, water-uracil and water-indole interactions are weak forces composed by smaller contributions from electrostatics, polarization, dispersion, and charge transfer. In addition, indole exhibits a negative electrostatic potential at its pi-face, making lp-pi interactions less favorable than O-H···pi hydrogen bonding. Consequently, some of the water-tryptophan contacts observed in X-ray structures of proteins and previously interpreted as lp-pi interactions [Luisi et al., Proteins 2004, 57, 1-8], might in fact arise from O-H···pi hydrogen bonding.
Related projects:

You are running an old browser version. We recommend updating your browser to its latest version.