Lone-pair–π interactions: analysis of the physical origin and biological implications
| Autor: | Jiří Kozelka, Jan Novotný, Radek Marek, Sophia Bazzi |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Indole test
Indoles 010405 organic chemistry Chemistry Band gap Hydrogen bond Static Electricity Tryptophan General Physics and Astronomy Electrons Hydrogen Bonding DNA Weak interaction 010402 general chemistry Electrostatics 01 natural sciences 0104 chemical sciences Protein structure Computational chemistry Chemical physics Static electricity Physical and Theoretical Chemistry Uracil Lone pair |
| Zdroj: | Physical Chemistry Chemical Physics. 18:19472-19481 |
| ISSN: | 1463-9084 1463-9076 |
| Popis: | Lone-pair-π (lp-π) 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, 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-π interactions between water and indole/uracil is significantly smaller than that stabilizing the Cl(-)-TCB reference system. The strong lp(Cl(-))-π(TCB) orbital interaction is characterized by a small energy gap and an efficient lp-π* overlap. In contrast, in lp-π 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 all energy components: electrostatics, polarization, dispersion, and charge transfer. In addition, indole exhibits a negative electrostatic potential at its π-face, making lp-π interactions less favorable than O-Hπ hydrogen bonding. Consequently, some of the water-tryptophan contacts observed in X-ray structures of proteins and previously interpreted as lp-π interactions [Luisi, et al., Proteins, 2004, 57, 1-8], might in fact arise from O-Hπ hydrogen bonding. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|