SPACI score report for 21gs in ASTRAL 1.73:

PDB Entry: 21gs
SPACI score: 0.44
AEROSPACI score: 0.44

Experiment type: XRAY
Resolution: 1.9
R-factor: 0.204
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 2
PCK3 PROCHECK H-bonds: 2
WCK1 WHAT_CHECK Packing: 0.071
WCK2 WHAT_CHECK Ramachandran: -0.226
WCK3 WHAT_CHECK Chi angles: -0.576
WCK4 WHAT_CHECK Backbone: -5.564

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).