SPACI score report for 1u91 in ASTRAL 1.73:

PDB Entry: 1u91
SPACI score: 0.34
AEROSPACI score: 0.34

Experiment type: XRAY
Resolution: 2.24
R-factor: 0.226
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 2
PCK3 PROCHECK H-bonds: 2
WCK1 WHAT_CHECK Packing: 1.906
WCK2 WHAT_CHECK Ramachandran: -0.306
WCK3 WHAT_CHECK Chi angles: -2.059
WCK4 WHAT_CHECK Backbone: -4.727

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).