Puckering Free Energy of Pyranoses Using a Combined Metadynamics-Umbrella Sampling Approach - Physics > Chemical PhysicsReport as inadecuate




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Abstract: We present the results of a combined metadynamics-umbrella samplinginvestigation of the puckered conformers of pyranoses described using thegromos 45a4 force field. The free energy landscape of Cremer-Pople puckeringcoordinates has been calculated for the whole series of alpha and betaaldohexoses. We show that the 45a4 force field parameters fail in reproducingproper free energy differences between chair conformers for many of theinspected monosaccharides. In the extreme cases of galactose, mannose andallose, the experimentally non-detectable inverted chair conformers become evensubstantially populated. The opposite behavior is observed in the case ofidose, which is the only experimentally known aldohexose that shows equilibriumbetween chair and inverted chair. We suggest a modification to the gromos 45a4parameter set, which improves considerably the accordance of simulation resultswith theoretical and experimental estimates of puckering free energies.



Author: E. Autieri, M. Sega, F. Pederiva

Source: https://arxiv.org/







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