SPACI score report for 4b3a in ASTRAL 2.05:

PDB Entry: 4b3a
SPACI score: 0.55
AEROSPACI score: 0.55

Experiment type: XRAY
Resolution: 1.7
R-factor: 0.2054
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 1
PCK3 PROCHECK H-bonds: 1
WCK1 WHAT_CHECK Packing: -0.012
WCK2 WHAT_CHECK Ramachandran: -0.841
WCK3 WHAT_CHECK Chi angles: -0.85
WCK4 WHAT_CHECK Backbone: 5.17

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).