SPACI score report for 2a8n in ASTRAL 2.06:

PDB Entry: 2a8n
SPACI score: 0.56
AEROSPACI score: 0.56

Experiment type: XRAY
Resolution: 1.6
R-factor: 0.225
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 1
PCK3 PROCHECK H-bonds: 1
WCK1 WHAT_CHECK Packing: -0.862
WCK2 WHAT_CHECK Ramachandran: -0.505
WCK3 WHAT_CHECK Chi angles: -0.024
WCK4 WHAT_CHECK Backbone: 0.532

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).