Dear charmm users, i actually try to build a ligand:receptor complex using charmming; habitually, i was using antechamber and gaff to build parameters for the ligand, but now i would like to build charmm (fully) compatible topologies/parameters files; i did not successed in building such files with charmming; any tutorial existing ?

nicolas floquet

You might want to look at the CHARMM General Force Field (CGENFF) and its associated references. There is a tutorial available for how to use it on Dr. MacKerrell's group web site.