SPACI score report for 4kg8 in ASTRAL 2.05:

PDB Entry: 4kg8
SPACI score: 0.34
AEROSPACI score: 0.34

Experiment type: XRAY
Resolution: 2.25
R-factor: 0.215
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 2
PCK3 PROCHECK H-bonds: 2
WCK1 WHAT_CHECK Packing: -1.03
WCK2 WHAT_CHECK Ramachandran: -3.004
WCK3 WHAT_CHECK Chi angles: -3.099
WCK4 WHAT_CHECK Backbone: 1.84

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).