Puckering free energy of pyranoses: A NMR and metadynamics-umbrella sampling investigation

被引：47
作者：
Autieri, E. [1 ,2 ]
Sega, M. [1 ,2 ]
Pederiva, F. [1 ,2 ]
Guella, G. [3 ]
机构：
[1] Univ Trento, Dept Phys, I-38123 Trento, Italy
[2] Univ Trento, Ist Nazl Fis Nucl, I-38123 Trento, Italy
[3] Univ Trento, Dept Phys, I-38123 Trento, Italy
来源：
JOURNAL OF CHEMICAL PHYSICS | 2010年 / 133卷 / 09期
关键词：
free energy; molecular configurations; NMR spectroscopy; nuclear magnetic resonance; organic compounds; MOLECULAR-DYNAMICS SIMULATIONS; CHAIR-BOAT TRANSITIONS; GROMOS FORCE-FIELD; QUANTITATIVE DESCRIPTION; BETA-CYCLODEXTRIN; 6-MEMBERED RINGS; AQUEOUS-SOLUTION; LOCAL ELEVATION; C-13; NMR; ALPHA;
D O I：
10.1063/1.3476466
中图分类号：
O64 [物理化学（理论化学）、化学物理学];
学科分类号：
070304 ; 081704 ;
摘要：
We present the results of a combined metadynamics-umbrella sampling investigation of the puckered conformers of pyranoses described using the GROMOS 45a4 force field. The free energy landscape of Cremer-Pople puckering coordinates has been calculated for the whole series of alpha and beta aldohexoses, showing that the current force field parameters fail in reproducing proper puckering free energy differences between chair conformers. We suggest a modification to the GROMOS 45a4 parameter set which improves considerably the agreement of simulation results with theoretical and experimental estimates of puckering free energies. We also report on the experimental measurement of altrose conformer populations by means of NMR spectroscopy, which show good agreement with the predictions of current theoretical models. (C) 2010 American Institute of Physics. [doi:10.1063/1.3476466]
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页数：14
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