PMF (Potential of Mean Force)
I. Muegge and Y.C. Martin, J. Med. Chem., 42, 791-804, 1999.
Atomtypes assigned by SMARTS rules. Problems with insufficient data in PDB for some atom types.
PLP (Piecewise Linear Potential)
D.K. Gehlhaar, G.M. Verkhiver, P.A. Reijto et al, Chem. Biol., 2, 317-324 (1995).
Simple, fast function may be more suitable than Lennard-Jones + electrostatics for optimization. Consistent assignment of hydrogen bond donor/acceptor may require tautomer and formal charge determination.