Topology and parameters for small organic molecules compatible with the CHARMM all atoms force field, for use with CHARMM and GROMACS

SwissParam is a webserver that provides topology and parameters for small organic molecules. These parameters are intended for drug design type calculations, such as docking, minimizations, rapid binding energy estimation (LIECE), etc.

Key features

  • Data derived from the Merck Molecular ForceField (MMFF), but in a functional form that is compatible with the CHARMM force field
  • Output files can be used with CHARMM or GROMACS
  • Only the harmonic part of the bond, angle and improper terms are retained
  • Van der Waals parameters are taken from the closest atom type in CHARMM22
  • Generated topologies and parameters are used by the docking software EADock2 and EADock DSS to describe the small molecules to be docked
  • Automatically used by SwissDock, a web server for docking small molecules to proteins
  • Rapid binding free energy estimation using SwissParam for ligands and CHARMM22/27 for proteins
  • Molecular dynamics simulation of a protein with a small-molecule ligand


V. Zoete, M. A. Cuendet, A. Grosdidier, O. Michielin, SwissParam, a Fast Force Field Generation Tool For Small Organic Molecules, J. Comput. Chem, 2011, 32(11), 2359-68. PMID: 21541964, DOI: 10.1002/jcc.21816.


SwissParam is developed and copyrighted by SIB Swiss Institute of Bioinformatics and its exclusive commercial representative GeneBio.
Access is free for non-commercial use. Access by commercial entities is subject to the licensing conditions outlined in the GeneBio License Agreement (PDF).

Please contact us for further details.

SwissParam website