SPACI score report for 1a6a in ASTRAL 1.75:

PDB Entry: 1a6a
SPACI score: 0.26
AEROSPACI score: 0.26

Experiment type: XRAY
Resolution: 2.75
R-factor: 0.246
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 2
PCK3 PROCHECK H-bonds: 2
WCK1 WHAT_CHECK Packing: -1.68
WCK2 WHAT_CHECK Ramachandran: -4.454
WCK3 WHAT_CHECK Chi angles: -3.271
WCK4 WHAT_CHECK Backbone: 0.275

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).