SPACI score report for 2zaa in ASTRAL 2.03:

PDB Entry: 2zaa
SPACI score: 0.55
AEROSPACI score: 0.55

Experiment type: XRAY
Resolution: 1.8
R-factor: 0.158
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 1
PCK3 PROCHECK H-bonds: 2
WCK1 WHAT_CHECK Packing: -1.105
WCK2 WHAT_CHECK Ramachandran: 0.39
WCK3 WHAT_CHECK Chi angles: 0.772
WCK4 WHAT_CHECK Backbone: 0.535

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).