OPLS force field

The optimized potentials for liquid simulations (OPLS) force-field was developed for the simulation of proteins and other organic liquids.

References

1. William L. Jorgensen and Julian Tirado-Rives "The OPLS (optimized potentials for liquid simulations) potential functions for proteins, energy minimizations for crystals of cyclic peptides and crambin", Journal of the American Chemical Society 110 pp. 1657 - 1666 (1988)
2. William L. Jorgensen and Toan B. Nguyen "Monte Carlo simulations of the hydration of substituted benzenes with OPLS potential functions", Journal of Computational Chemistry 14 pp. 195 - 205 (1993)

OPLS-all atom

(OPLS-AA)

Form of the force field

Bond stretching

$E_{\rm {bond}}=\sum _{\rm {bonds}}K_{r}\left(r-r_{eq}\right)^{2}$

Angle bending

$E_{\rm {angle}}=\sum _{\rm {angles}}K_{\theta }\left(\theta -\theta _{eq}\right)^{2}$

Torsion

$E(\phi )={\frac {V_{1}}{2}}\left[1+\cos(\phi +f1)\right]+{\frac {V_{2}}{2}}\left[1-\cos(2\phi +f2)\right]+{\frac {V_{3}}{2}}\left[1+\cos(3\phi +f3)\right]$

Non-bonded

$E_{ab}=\sum _{i}^{\rm {on~a}}\sum _{j}^{\rm {on~b}}\left[{\frac {q_{i}q_{j}e^{2}}{r_{ij}}}+4\epsilon _{ij}\left({\frac {\sigma _{ij}^{12}}{r_{ij}^{12}}}-{\frac {\sigma _{ij}^{6}}{r_{ij}^{6}}}\right)\right]f_{ij},~~~~f_{ij}=\left\{{\begin{array}{lll}0.5&;&{\rm {if}}~~i,j=1,4\\1&;&{\rm {otherwise}}\end{array}}\right.$

References

1. Wolfgang Damm, Antonio Frontera, Julian Tirado-Rives and William L. Jorgensen "OPLS all-atom force field for carbohydrates", Journal of Computational Chemistry 18 pp. 1955 - 1970 (1997)
2. William L. Jorgensen, David S. Maxwell, and Julian Tirado-Rives "Development and Testing of the OPLS All-Atom Force Field on Conformational Energetics and Properties of Organic Liquids", Journal of the American Chemical Society 118 pp. 11225 - 11236 (1996)
   1. Electronic Supporting Information