OPLS Force Fields

forcefield

A force field is a model of the potential energy of a chemical system. It is a set of functions and parameters used to model the potential energy of the system, and thereby to calculate the forces on each particle.

OPLS4

The OPLS4 force field extends the OPLS3e [63], OPLS3 [62] and OPLS_2005 force fields to cover a much wider range of chemical space with better accuracy. This force field can be customized by using the Force Field Builder - OPLS4/OPLS5 Panel.

In input and output files, the string OPLS4 is used to refer to the OPLS4 force field. Note that the OPLS4 force field is called S-OPLS in command-line applications.

When using this force field, please use the following citation:

  • OPLS4, Schrödinger, Inc., New York, NY, 2021

In addition, please also cite the following paper:

  • Lu, C.; Wu, C.; Ghoreishi, D.; Chen, W.; Wang, L.; Damm, W.; Ross, G. A.; Dahlgren, M. K.; Russell, E.; Von Bargen, C. D.; Abel, R.; Friesner. R. A.; Harder, E.; OPLS4: Improving Force Field Accuracy on Challenging Regimes of Chemical Space. J. Chem. Theory Comput.2021, 17, 4291. DOI: 10.1021/acs.jctc.1c00302

 

OPLS5

The OPLS5 force field offers improved accuracy compared to the OPLS4 force field, but shows slower performance. This force field can be customized by using the Force Field Builder - OPLS4/OPLS5 Panel.

In input and output files, the string OPLS5 is used to refer to the OPLS5 force field. Note that the OPLS5 force field is called SPFF in command-line applications

When using this force field, please use the following citation:

  • OPLS5, Schrödinger, Inc., New York, NY, 2021

 

OPLS_2005

OPLS_2005 is an enhanced version of the OPLS_2001 all atom force field developed by Schrödinger to provide a larger coverage of organic functionality. While retaining the features of OPLS-AA and OPLS_2001, torsional parameters have been refit to reproduce the conformational energetics derived at a higher level of quantum theory; additional stretch, bend, and torsion parameters and charges have been fit to support additional organic functionality. A much larger data set was analyzed for validation of the force field. The parameters for proteins have been updated to the ones published more recently [53].

Note: The OPLS_2001 force field is now considered obsolete and is no longer available. The following information is retained for its connection with OPLS_2005:

OPLS_2001 (or OPLSAA), developed by Professor W. Jorgensen of Yale University, is probably the best available for condensed-phase simulations of peptides. All force-field equations are identical to those of authentic OPLSAA [17]. Schrödinger’s implementation has been validated by comparison to BOSS OPLSAA calculations for a wide variety of organic systems. Comparisons to ab initio calculations and experiment show that OPLS_2001 reproduces conformational energies well for systems for which it has been specifically parameterized. Especially good results can be expected for proteins. With the exception of improved charge, van der Waals and torsion parameters for sulfur in thiols and thiol ethers [18], all parameters are native OPLS_2001. The new thio parameters, which use appreciably smaller charges on sulfur and which have been validated in liquid-phase simulations on thiols and thiol ethers, significantly improve the conformational energetics of CYS and MET residues in proteins.