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Adsorption of Amino Acids on Graphene: Assessment of Current Force Fields

preprint
revised on 30.01.2019 and posted on 30.01.2019 by Siva Dasetty, John K. Barrows, Sapna Sarupria

We compare the free energies of adsorption (∆Aads) and the structural preferences of amino acids obtained using the force fields — Amberff99SB-ILDN/TIP3P, CHARMM36/modified-TIP3P, OPLS-AA/M/TIP3P, and Amber03w/TIP4P/2005. The amino acid–graphene interactions are favorable irrespective of the force field. While the magnitudes of ∆Aads differ between the force fields, the trends in the free energy of adsorption with amino acids are similar across the studied force fields. ∆Aads positively correlates with amino acid–graphene and negatively correlates with graphene–water interaction energies. Using a combination of principal component analysis and density-based clustering technique, we grouped the structures observed in the graphene adsorbed state. The resulting population of clusters, and the conformation in each cluster indicate that the structures of the amino acid in the graphene adsorbed state vary across force fields. The differences in the conformations of amino acids are more severe in the graphene adsorbed state compared to the bulk state for all the force fields. Our findings suggest that while the thermodynamics of adsorption of proteins and peptides would be described consistently across different force fields, the structural preferences of peptides and proteins on graphene will be force field dependent.

Funding

HDTRA-1-16- 1-0023

History

Email Address of Submitting Author

sdasett@g.clemson.edu

Institution

Clemson University

Country

United States of America

ORCID For Submitting Author

0000-0002-1666-7980

Declaration of Conflict of Interest

No conflict of interest.

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