SPACI score report for 2a31 in ASTRAL 2.01:

PDB Entry: 2a31
SPACI score: 0.82
AEROSPACI score: 0.82

Experiment type: XRAY
Resolution: 1.25
R-factor: 0.14
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 1
PCK3 PROCHECK H-bonds: 2
WCK1 WHAT_CHECK Packing: 2.846
WCK2 WHAT_CHECK Ramachandran: -0.669
WCK3 WHAT_CHECK Chi angles: 1.312
WCK4 WHAT_CHECK Backbone: 1.718

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).