SPACI score report for 1t6t in ASTRAL 2.06:

PDB Entry: 1t6t
SPACI score: 0.54
AEROSPACI score: 0.54

Experiment type: XRAY
Resolution: 1.8
R-factor: 0.18
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 1
PCK3 PROCHECK H-bonds: 2
WCK1 WHAT_CHECK Packing: -0.714
WCK2 WHAT_CHECK Ramachandran: -0.212
WCK3 WHAT_CHECK Chi angles: 3.552
WCK4 WHAT_CHECK Backbone: 4.408

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).