SPACI score report for 1kxx in ASTRAL 1.73:

PDB Entry: 1kxx
SPACI score: 0.52
AEROSPACI score: 0.52 (mutant; see below)

Experiment type: XRAY
Resolution: 1.71
R-factor: 0.177
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 2
PCK3 PROCHECK H-bonds: 2
WCK1 WHAT_CHECK Packing: -0.401
WCK2 WHAT_CHECK Ramachandran: -1.297
WCK3 WHAT_CHECK Chi angles: -1.511
WCK4 WHAT_CHECK Backbone: -3.931

The AEROSPACI score for this entry is lower than the SPACI score because human-curated comments on the entry in SCOP contain the phrase mutant. The full comment is: "mutant"

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).