SPACI score report for 1nat in ASTRAL 1.73:

PDB Entry: 1nat
SPACI score: 0.33
AEROSPACI score: 0.33

Experiment type: XRAY
Resolution: 2.45
R-factor: 0.181
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 2
PCK3 PROCHECK H-bonds: 2
WCK1 WHAT_CHECK Packing: -0.333
WCK2 WHAT_CHECK Ramachandran: -2.784
WCK3 WHAT_CHECK Chi angles: -2.872
WCK4 WHAT_CHECK Backbone: -4.763

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).