SPACI score report for 1a6w in ASTRAL 1.55:

PDB Entry: 1a6w
SPACI score: 0.53
AEROSPACI score: 0.53

Experiment type: XRAY
Resolution: 1.8
R-factor: 0.171
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 1
PCK3 PROCHECK H-bonds: 2
WCK1 WHAT_CHECK Packing: -1.728
WCK2 WHAT_CHECK Ramachandran: -0.375
WCK3 WHAT_CHECK Chi angles: 0.508
WCK4 WHAT_CHECK Backbone: 0.563

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).