کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1388799 | 982818 | 2009 | 7 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Metadynamics modelling of the solvent effect on primary hydroxyl rotamer equilibria in hexopyranosides Metadynamics modelling of the solvent effect on primary hydroxyl rotamer equilibria in hexopyranosides](/preview/png/1388799.png)
Accurate modelling of rotamer equilibria for the primary hydroxyl groups of monosaccharides continues to be a great challenge of computational glycochemistry. The metadynamics technique was applied to study the conformational free energy surfaces of methyl α-d-glucopyranoside and methyl α-d-galactopyranoside, employing the glycam06 force field. For both molecules, seven to eight conformational free-energy minima, differing in the ω (O-5–C-5–C-6–O-6) and χ (C-3–C-4–O-4–HO-4) dihedral angles, were identified in vacuum or in a water environment. The calculated rotamer equilibrium of the primary hydroxyl group is significantly different in vacuum than in water. The major effect of a water environment is the destabilisation of a hydrogen bond between O-4–HO-4 and O-6–HO-6 groups. It was possible to calculate the free-energy differences of individual rotamers with an accuracy of better than 2 kJ/mol. The calculated gg, gt and tg rotamer populations in water are in close agreement with experimental measurements, and therefore support the theoretical background of metadynamics.
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Journal: Carbohydrate Research - Volume 344, Issue 12, 17 August 2009, Pages 1575–1581