[ccp4bb] How do I set up a Refmac5 dictionary to constrain octahedrally coordinated Ca++

Dear all, How do I set up a Refmac dictionary to constrain octahedrally coordinated Ca++? Refmac5 seems to detect the potential bond between the Ca++ and the ligands: INFO: link is found (not be used) dist= 2.229 ideal_dist= 2.320 ch:AA res: 263 GLU at:O .-ch:Ag

Re: [ccp4bb] How do I set up a Refmac5 dictionary to constrain octahedrally coordinated Ca++

Pietro, You will need to set "Make links between: All others if...residues are close only" in the Refmac GUI and write out a .cif file for the Ca-ligand distance restraints. See this link:

Re: [ccp4bb] How do I set up a Refmac5 dictionary to constrain octahedrally coordinated Ca++

Hi Pietro, There are monomer library entries for Ca in various states of coordination by water, entries, OC1, OC2,OC3 etc but unfortunately these are incomplete (no distances or angles with sd's), at least in our CCP4 installation. The entry for octahedral MG-O6, file MO6, is complete