SPACI score report for 1t6a in ASTRAL 2.08:

PDB Entry: 1t6a
SPACI score: 0.46
AEROSPACI score: 0.46

Experiment type: XRAY
Resolution: 2.05
R-factor: 0.196
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 1
PCK3 PROCHECK H-bonds: 2
WCK1 WHAT_CHECK Packing: 0.582
WCK2 WHAT_CHECK Ramachandran: 1.662
WCK3 WHAT_CHECK Chi angles: 2.475
WCK4 WHAT_CHECK Backbone: 1.912

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).