Assessing the accuracy of the general AMBER force field for 2,2,2-trifluoroethanol as solvent.

The alcohol-based cosolvent 2,2,2-trifluoroethanol (TFE) has been used widely in protein science and engineering. Many experimental and computational studies of its impact on protein structure have been carried out, but consensus on the mechanism has not been reached. In the past decade, several molecular mechanical models have been proposed to model the structure and dynamics of TFE. However, further calibration is still necessary. In particular, its compatibility with protein force fields has not been well examined. The general AMBER force field (GAFF) has proved quite successful in modeling small organic molecules, and is compatible with contemporary AMBER force field. In this work, we assessed the accuracy of GAFF for the TFE molecule as a bulk solvent. Several properties, such as density, dipole moment, radial distribution function, etc., were calculated and compared with experimental data. The results show that GAFF plays fairly well in the description of bulk TFE, although there is still room for improvement.