SPACI score report for 3tgg in ASTRAL 2.07:

PDB Entry: 3tgg
SPACI score: 0.5
AEROSPACI score: 0.5

Experiment type: XRAY
Resolution: 1.91
R-factor: 0.188
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 1
PCK3 PROCHECK H-bonds: 1
WCK1 WHAT_CHECK Packing: -0.153
WCK2 WHAT_CHECK Ramachandran: 1.18
WCK3 WHAT_CHECK Chi angles: -0.664
WCK4 WHAT_CHECK Backbone: 1.19

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).