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Modelling of beta-D-glucopyranose ring distortion in different force fields: a metadynamics study
Vojtech Spiwok1, Blanka Králová, Igor Tvaroska
1Department of Biochemistry and Microbiology, Institute of Chemical Technology Prague, Technická 3, Prague, Czech Republic. spiwokv@vscht.cz
Carbohydrate Research
|January 8, 2010
Summary
Accurate modeling of carbohydrate conformations is crucial. Three force fields (GLYCAM06, GROMOS 45a4, OPLS) were tested for beta-D-glucopyranose, finding the (4)C(1) conformation most stable across all. Water had a minor stabilizing effect.
Area of Science:
- Computational chemistry
- Molecular modeling
- Carbohydrate chemistry
Background:
- Accurate modeling of carbohydrate conformations is essential for understanding their biological roles.
- Existing molecular mechanics force fields require rigorous evaluation for carbohydrate systems.
- Beta-D-glucopyranose serves as a model monosaccharide for conformational studies.
Purpose of the Study:
- To evaluate the performance of three common carbohydrate force fields: GLYCAM06, GROMOS 45a4, and OPLS.
- To determine the free energy landscapes of beta-D-glucopyranose ring conformations in vacuum and aqueous environments.
- To compare computational results with experimental data and other simulation studies.
Main Methods:
- Metadynamics simulations were employed to explore the conformational space of beta-D-glucopyranose.
- Free energies of different ring conformations were calculated in both vacuum and explicit water.
- The stability and interconversion barriers between conformations were analyzed for each force field.
Main Results:
- All three force fields consistently identified the (4)C(1) conformation as the most stable for beta-D-glucopyranose, with an energy difference of at least 6 kJ/mol.
- Conformational interconversions from (4)C(1) exhibited energy barriers of no less than 26 kJ/mol.
- The GLYCAM06 force field demonstrated excellent agreement with previous Car-Parrinello metadynamics studies.
- Explicit water molecules exerted a similar, relatively small stabilizing effect on specific conformations ((3,O)B vs. B(3,O)) across all force fields.
Conclusions:
- The evaluated force fields (GLYCAM06, GROMOS 45a4, OPLS) provide a reasonable description of beta-D-glucopyranose ring conformations.
- The (4)C(1) conformation is robustly predicted as the most stable.
- The influence of the aqueous environment on the conformational free energy landscape is modest and consistent across the tested force fields.
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