SPACI score report for 2a6b in ASTRAL 2.08:

PDB Entry: 2a6b
SPACI score: 0.59
AEROSPACI score: 0.59

Experiment type: XRAY
Resolution: 1.7
R-factor: 0.155
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 1
PCK3 PROCHECK H-bonds: 2
WCK1 WHAT_CHECK Packing: -0.625
WCK2 WHAT_CHECK Ramachandran: 1.315
WCK3 WHAT_CHECK Chi angles: 0.942
WCK4 WHAT_CHECK Backbone: 0.94

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).