SPACI score report for 4i6n in ASTRAL 2.03:

PDB Entry: 4i6n
SPACI score: 0.56
AEROSPACI score: 0.56

Experiment type: XRAY
Resolution: 1.7
R-factor: 0.176
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 1
PCK3 PROCHECK H-bonds: 2
WCK1 WHAT_CHECK Packing: -1.24
WCK2 WHAT_CHECK Ramachandran: -0.831
WCK3 WHAT_CHECK Chi angles: -0.548
WCK4 WHAT_CHECK Backbone: 3.036

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).