SPACI score report for 2xnb in ASTRAL 2.07:

PDB Entry: 2xnb
SPACI score: 0.42
AEROSPACI score: 0.42

Experiment type: XRAY
Resolution: 1.85
R-factor: 0.21557
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 3
PCK3 PROCHECK H-bonds: 2
WCK1 WHAT_CHECK Packing: -2.176
WCK2 WHAT_CHECK Ramachandran: -2.358
WCK3 WHAT_CHECK Chi angles: -3.909
WCK4 WHAT_CHECK Backbone: 0.454

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).