<html><body style='font-family:Calibri, Arial, Helvetica, sans-serif;font-size:11pt;color:black' >So the resolution is 1.6 and I remember the B factor for mg at 16. I haven't checked the coordinating residues. It coordinates acidic residues, a backbone carbonyl and one water. I'm now leaning towards calcium as the other calciums have bonds distances similar to this one, but not nearly as high an affinity.<br><br>Thanks</body></html>