Hi! I could successfully refine a merohedral twin in phenix.refine but I have a few unanswered questions: 1. Is there a way of applying antibumping restraints to decrease the number of clashes in phenix.refine, I looked at older posts but couldn't get a satisfactory guideline regarding the same. 2. The default setttings for geometry refinement looks like this: refinement.geometry_restraints.remove { angles = None dihedrals = None chiralities = None planarities = None } Do I have to change "dihedrals=True" if I do not want to put restraints on dihedrals. I was thinking that one puts restraints on psi/phi angles only by setting "discard_psi_phi = False" because when I set it to "discard_psi_phi = True", the Ramachandran plot was much better. But I did not want to do this because then the Ramachandran plot is no more a validation tool. I just wanted to know if Unknowingly I did that by setting up "dihedrals = None". Thank you in advance. Regards, Madhu. ------------------------------------------ Madhumati Sevvana, PhD Lehrstuhl fuer Biotechnik Friedrich-Alexander-Universitaet Henkestr. 91, D-91052 Erlangen, Germany Tel: 0049-9131-8523083 Email: [email protected] -------------------------------------------