Dear phenix users, I am currently building a model where the ligand is linked via schiff base to a lysine residue. To let phenix know about the link I provide the ligand.cif file and created the link parameter file as described in the manual. The type of link I defined with Jligand as it does not appear in the standard ccp4 library. Unfortunately phenix.refine stops with the error message below when I provide the so created files. It seems phenix has problems to apply the needed ligand modifications ie removing hydrogens and oxygens and stops with the refinement. I have no idea why this doesn't work and am getting a little desperate so any suggestions how to do this properly would be greatly appreciated. Could I use for example elBOW to create the link description? many thanks, Joerg File "/lmb/home/public/xtal/Phenix/phenix-1.4-3/mmtbx/ monomer_library/pdb_interpretation.py", line 499, in __init__ mod_mod_id=self.mon_lib_srv.mod_mod_id_dict[apply_data_mod]) File "/lmb/home/public/xtal/Phenix/phenix-1.4-3/mmtbx/ monomer_library/pdb_interpretation.py", line 771, in apply_mod mod_mon = self.monomer.apply_mod(mod_mod_id) File "/lmb/home/public/xtal/Phenix/phenix-1.4-3/mmtbx/ monomer_library/cif_types.py", line 339, in apply_mod result.delete_atom_in_place(mod_atom.atom_id) File "/lmb/home/public/xtal/Phenix/phenix-1.4-3/mmtbx/ monomer_library/cif_types.py", line 244, in delete_atom_in_place raise RuntimeError("delete_atom_in_place: unknown atom_id: %s" % atom_id) RuntimeError: delete_atom_in_place: unknown atom_id: H151