SPACI score report for 3b6f in ASTRAL 2.06:

PDB Entry: 3b6f
SPACI score: 0.02
AEROSPACI score: 0.02

Experiment type: XRAY
Resolution: 3.45
R-factor: 0.331
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 3
PCK3 PROCHECK H-bonds: 3
WCK1 WHAT_CHECK Packing: -3.298
WCK2 WHAT_CHECK Ramachandran: -6.437
WCK3 WHAT_CHECK Chi angles: -5.239
WCK4 WHAT_CHECK Backbone: -1.025

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).