SPACI score report for 4b3k in ASTRAL 2.03:

PDB Entry: 4b3k
SPACI score: 0.27
AEROSPACI score: 0.27

Experiment type: XRAY
Resolution: 2.6
R-factor: 0.22594
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 2
PCK3 PROCHECK H-bonds: 2
WCK1 WHAT_CHECK Packing: -1.398
WCK2 WHAT_CHECK Ramachandran: -3.5
WCK3 WHAT_CHECK Chi angles: -2.67
WCK4 WHAT_CHECK Backbone: 2.349

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).