SPACI score report for 1b6s in ASTRAL 2.07:

PDB Entry: 1b6s
SPACI score: 0.29
AEROSPACI score: 0.29

Experiment type: XRAY
Resolution: 2.5
R-factor: 0.185
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 3
PCK3 PROCHECK H-bonds: 3
WCK1 WHAT_CHECK Packing: -2.147
WCK2 WHAT_CHECK Ramachandran: -2.633
WCK3 WHAT_CHECK Chi angles: -4.553
WCK4 WHAT_CHECK Backbone: -0.212

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).