SPACI score report for 1by4 in ASTRAL 2.07:

PDB Entry: 1by4
SPACI score: 0.28
AEROSPACI score: 0.28

Experiment type: XRAY
Resolution: 2.1
R-factor: 0.234
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 4
PCK3 PROCHECK H-bonds: 3
WCK1 WHAT_CHECK Packing: -3.849
WCK2 WHAT_CHECK Ramachandran: -5.125
WCK3 WHAT_CHECK Chi angles: -5.609
WCK4 WHAT_CHECK Backbone: -1.885

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).