Evaluation of the GROMOS 56ACARBO Force Field for the Calculation of Structural, Volumetric, and Dynamic Properties of Aqueous Glucose Systems

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• 作者：Marta L. S. Batista ; Germ谩n P茅rez-S谩nchez ; Jos茅 R. B. Gomes ; Jo茫o A. P. Coutinho ; Edward J. Maginn
• 刊名：Journal of Physical Chemistry B
• 出版年：2015
• 出版时间：December 10, 2015
• 年：2015
• 卷：119
• 期：49
• 页码：15310-15319
• 全文大小：541K
• ISSN：1520-5207

文摘

Glucose is an important carbohydrate, relevant both for its biological functions and as a raw material for industrial processes. As a monomer of cellulose, the most abundant biopolymer, it is an alternative feedstock for fuels and chemicals in the biorefinery framework. Since glucose is often used and processed in aqueous solutions, it is important to understand the structural, volumetric, and dynamic properties of aqueous glucose solutions at varying concentrations. Molecular dynamics (MD) simulations are an effective means for computing the properties of liquid solutions, but the technique relies upon accurate intermolecular potential functions (i.e., 鈥渇orce fields鈥?. Here we evaluate the accuracy of the recently developed GROMOS 56A_CARBO glucose force field for its ability to model the density, viscosity, and self-diffusivity of aqueous glucose solutions as a function of concentration. We also compute different structural properties, including hydrogen bonds, radial and spatial distribution functions, and coordination numbers. The results show that the force field accurately models the density and viscosity of dilute solutions up to a glucose mole fraction of 0.1. At higher glucose concentrations, the force field overestimates the experimental density and viscosity. By analyzing the liquid structure, it is found that the glucose molecules tend to associate at higher concentrations, which leads to deviation from the experimental results. This suggests that, while the GROMOS 56A_CARBO force field performs well for highly dilute glucose solutions (conditions under which it was developed), it is not appropriate for carrying out simulations of more concentrated glucose solutions. It is possible to obtain much more accurate densities and viscosities at high glucose concentrations by uniformly reducing the partial charges on glucose by 20%, which attenuates the self-association tendencies of glucose.