Hi all, I have a protein-DNA structure at 3 angstroms that I have been refining with refmac5. I have recently started to look into using phenix.refine instead. However, I am still having some problems with the sugar puckering of my DNA which is an ideal B-DNA and should be kept C2'-endo, but keeps changing to C1'-exo or C3'-endo after refinement with phenix. I have looked at the .cif files for the DNA and may update the restraints. Is this the easiest way to go about restraining the sugar puckering? Thank you, Yu Seon Chung