Hi, I am trying to solve a structure of a protein that is cocrystallized with a chelator complex using phenix (GUI). The complex is Tb(DPA)3 and DPA stands for dipicolinic acid. In the structure (C222) there are few Tb complexes on the two fold axis with symmetry coordinates 1/4X, 1/4Y, Z. In those, Tb and the center C (C4) and N (N1) of one DPA are sitting directly on the 2 fold axis. So I left only half of that DPA ligand structure on PDB file and changed the occupancy of N1 and C4 to 1/2 while keeping the occupancy of all other atoms of the half ligand structure at 1.00. Then I refined it while keeping above occupancies and xyz coordinated of the ligand fixed. After doing this the other half of the ligand could be built by symmetry, but it left a space between two halves(so it was not as one ligand). Can you please let me know what I can do to fix this structure. Also is there a way to keep only x and y coordinates fixed while varying z during refinement. Thanks Subhani