SPACI score report for 4ac9 in ASTRAL 2.08:

PDB Entry: 4ac9
SPACI score: 0.25
AEROSPACI score: 0.25

Experiment type: XRAY
Resolution: 3.03
R-factor: 0.1913
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 2
PCK3 PROCHECK H-bonds: 2
WCK1 WHAT_CHECK Packing: -1.464
WCK2 WHAT_CHECK Ramachandran: -2.026
WCK3 WHAT_CHECK Chi angles: -3.119
WCK4 WHAT_CHECK Backbone: 2.048

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).