I was performing MD simulation for protein-ligand complex following [GROMACS tutorial][1]. I compared the energy of two ligands (S1 and S2) to a protein, using GROMACS **LJ-SR** (Lennard-Jones Short Range) and **Coul-SR** (Coulombic Short Range) option. Below is the plot. [![enter image description here][2]][2] As you can see the LJ-SR is complete opposite of Coul-SR. Are they expected to be the opposite? Which is more appropriate choice to represent real binding energy? [1]: http://www.mdtutorials.com/gmx/complex/09_analysis.html [2]: https://i.sstatic.net/fTY3N.png