(660i) The Open Force Field v2.0 and Extensions to Biopolymers

The Open Force Field Initiative (OpenFF), at https://openforcefield.org, is academic/industrial collaboration focused on the development of 1) extensible, open source toolkits for constructing, applying, and evaluating force fields; 2) the curation of public datasets necessary to build high-accuracy biomolecular force fields; and 3) the generation of improved molecular force fields for biomolecular and other soft matter applications. The effort is designed to improve the reproducibility and openness of the development of classical force fields for quantitative molecular exploration, prediction, and design.

In this talk, I will discuss the Open Force Field version 2.0 force field, “Sage”, and the improvements that have gone into this latest version, including using heats of mixing and composition-dependent density to improve Lennard-Jones parameters. I will also discuss procedures to extend the Open Force small molecule force fields to biopolymers in a way that preserves complete chemical transferability; in other words, that the parameters assigned to chemical moieties are completely transferable between small molecules, biopolymers and other chemical environments of interest. I will also discuss our broader collaborative effort to develop validation sets to determine the extent to which a force field accurately models protein structure. Finally, I will discuss the next steps in force field development, including the fitting and testing of off-atom charge sites to better describe electrostatics, a graph convolutional neural network procedure to assign charges that scales linearly with molecular size, and surrogate modeling approaches to speed and even improve the optimization of nonbonded force field parameters.