SPACI score report for 3ad4 in ASTRAL 2.06:

PDB Entry: 3ad4
SPACI score: 0.42
AEROSPACI score: 0.42

Experiment type: XRAY
Resolution: 2.2
R-factor: 0.177
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 1
PCK3 PROCHECK H-bonds: 2
WCK1 WHAT_CHECK Packing: -1.146
WCK2 WHAT_CHECK Ramachandran: -0.347
WCK3 WHAT_CHECK Chi angles: -0.927
WCK4 WHAT_CHECK Backbone: 0.753

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).