SPACI score report for 1b4a in ASTRAL 1.55:

PDB Entry: 1b4a
SPACI score: 0.28
AEROSPACI score: 0.28

Experiment type: XRAY
Resolution: 2.5
R-factor: 0.224
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 3
PCK3 PROCHECK H-bonds: 2
WCK1 WHAT_CHECK Packing: 0.275
WCK2 WHAT_CHECK Ramachandran: -0.523
WCK3 WHAT_CHECK Chi angles: -3.299
WCK4 WHAT_CHECK Backbone: 0.958

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).