After validating a PDB for deposition I received a message that the HEME ligand C2D-C3D distance was longer than ideal. It was 1.52 angstroms, while it was 1.35 for C2A-C3A, C2B-C3B and C2C-C3C.

The ideal bond length is listed as  1.544 vs. 1.337 for the other bonds in $PHENIX/chem_data/mon_lib/h/HEM.cif

Is there a reason for this? If not, I am inclined to edit it.

-Yarrow