STUDY OF THE ADDITIVE PROPERTIES OF THE CARBOHYDRATE AROMATIC CH-Pi INTERACTION BY THE DFT AND AB INITIO CALCULATIONS
| Autoři | |
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| Rok publikování | 2012 |
| Druh | Konferenční abstrakty |
| Fakulta / Pracoviště MU | |
| Citace | |
| Popis | The CH/pi interactions that occur between carbohydrates and aromatic amino-acids are strongly involved in carbohydrate-recognition process. However, their influence to the recognition process has been underestimated for a long time. It has been recently shown that the strength of the CH/pi interactions is comparable to classical hydrogen bond. Presented computational study aims to describe the degree of additivity of the CH/pi interaction analyzing the interaction energy of carbohydrate-benzene complexes with monodentate (one CH/pi contact) and bidentate (two CH/pi contacts) carbohydrate-naphtalene complexes. All model complexes were optimized at DFT-D BP/def2 TZVPP level of theory, followed by refinement of interaction energies at highly-correlated and accurate CCSD(T)/CBS level. Also Boltzmann weighted populations of naphtalene/carbohydrate complexes were calculated for each carbohydrate apolar face.Deeper analysis discovers certain measurable degree of additivity. More precisely, the interaction energy of bidentate complex is 2/3 of the sum of interaction energies of appropriate monodentate complexes. Similarly, the interaction energy value for bidentante carbohydrate-naphtalene complexes is comparable to 4/5 of the sum of interaction energies of corresponding carbohydrate-benzene complexes. The study also shows that DFT-D methods describe CH/pi interactions in qualitatively similar manner as more computationally demanding CCSD(T)/CBS method. Based on our observations, we can conclude that DFTD approach may be utilized for computational treatment of larger complexes of biological interest, where CH/pi dispersion interactions play non-negligible role. |
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