Hi

Could somebody please give some clarification on how charmm deals with possible torsion angles (and associated degrees of freedom?). That is, are all possible torsions explicitely represented?.
I am trying to parameterise a ligand based on existing paramater entries, but, for example, I don't find any dihedrals (all27_prot_na) with a terminal "S" atom type. However, such torsions exist in methionine.

Thanks
Gordon Wells

Hi Gordon,

The X atom type is a wildcard and matches any atom type, so dihedral terms with a sulfur at the end would be covered by definitions like X C C X (if there are no S-specific terms).