SPACI score report for 3gb3 in ASTRAL 2.03:

PDB Entry: 3gb3
SPACI score: 0.51
AEROSPACI score: 0.51

Experiment type: XRAY
Resolution: 1.75
R-factor: 0.189
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 2
PCK3 PROCHECK H-bonds: 2
WCK1 WHAT_CHECK Packing: -2.129
WCK2 WHAT_CHECK Ramachandran: 0.066
WCK3 WHAT_CHECK Chi angles: -1.358
WCK4 WHAT_CHECK Backbone: 0.327

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).