SPACI score report for 3p6a in ASTRAL 2.07:

PDB Entry: 3p6a
SPACI score: 0.29
AEROSPACI score: 0.29

Experiment type: XRAY
Resolution: 2.5
R-factor: 0.228
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 2
PCK3 PROCHECK H-bonds: 2
WCK1 WHAT_CHECK Packing: -0.072
WCK2 WHAT_CHECK Ramachandran: -2.12
WCK3 WHAT_CHECK Chi angles: -2.48
WCK4 WHAT_CHECK Backbone: -0.093

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).