SPACI score report for 2b4s in ASTRAL 1.73:

PDB Entry: 2b4s
SPACI score: 0.37
AEROSPACI score: 0.37

Experiment type: XRAY
Resolution: 2.3
R-factor: 0.208
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 1
PCK3 PROCHECK H-bonds: 2
WCK1 WHAT_CHECK Packing: -0.181
WCK2 WHAT_CHECK Ramachandran: -0.125
WCK3 WHAT_CHECK Chi angles: 0.371
WCK4 WHAT_CHECK Backbone: -2.812

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).