Systematic Study of Carbohydrate-Aromatic CH-pi Dispersion Interaction by DFT and Highly Correlated Ab Initio Methods
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| Year of publication | 2011 |
| Type | Conference abstract |
| MU Faculty or unit | |
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| Description | The protein-carbohydrate interactions play essential role in various biologically important issues as pathogene identification, host-guest recognition, intercellular signalling, cell growth and differentiation etc. Non-negligible part of protein-cabohydrate interactions is mediated by CH-pi interactions, which were proved to have strong dispersion character. This study introduces first systematic study of the nature of the CH-pi dispersion interactions between benzene as model for aromatic amino-acids in proteins and three carbohydrates b-D-glucopyranose, b-D-mannopyranose and a-L-fucopyranose. The 3D relaxed scan of interaction energy (E) surface between carbohydrate and benzene was performed at SCC-DFTB-D level, followed by DFT-D BP/def2-TZVPP E evaluation and reoptimization of most stable structures. These structures were used for evaluation of E at MP2/CBS and CCSD(T)/CBS level. Obtained results show that E between apolar faces of carbohydrates and benzene grows up to -5.40 kcal/mol, which corresponds to medium-strong hydrogen bond. Additionally, the aromatic moiety binds most strongly above and under CH-groups of the carbohydrate -the strongest interaction is localized and the aromatic ring is able to recognize specific hydrogens of the saccharide in specific distance. The geometries of most stable benzene-carbohydrate complexes were measured to discover, that most suitable distance between carbohydrate hydrogen and the benzene center is around 2.3 A and the C-H-benzene-center angle slightly varies around 180deg. |
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