SPACI score report for 4g51 in ASTRAL 2.07:

PDB Entry: 4g51
SPACI score: 0.29
AEROSPACI score: 0.29

Experiment type: XRAY
Resolution: 2.5
R-factor: 0.181
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 3
PCK3 PROCHECK H-bonds: 3
WCK1 WHAT_CHECK Packing: -1.844
WCK2 WHAT_CHECK Ramachandran: -5.245
WCK3 WHAT_CHECK Chi angles: -5.735
WCK4 WHAT_CHECK Backbone: 4.502

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).