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

[Pietro Roversi]

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   res: 600  CA       
at:CA  .

but it does not enforce them, and I cannot figure out what the
CCP4 convention for a O-Ca++ bond is.

Thanks for any suggestions!

Pietro