SPACI score report for 1m56 in ASTRAL 1.65:

PDB Entry: 1m56
SPACI score: 0.31
AEROSPACI score: 0.31

Experiment type: XRAY
Resolution: 2.3
R-factor: 0.236
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 2
PCK3 PROCHECK H-bonds: 2
WCK1 WHAT_CHECK Packing: -1.574
WCK2 WHAT_CHECK Ramachandran: -3.783
WCK3 WHAT_CHECK Chi angles: -2.362
WCK4 WHAT_CHECK Backbone: -0.052

Note: Here are links to pages about PROCHECK and WHAT_CHECK.

Here is the full WHAT_CHECK report on this protein (linked from the WHAT_CHECK site).