SPACI score report for 4ls6 in ASTRAL 2.08:

WARNING! The SPACI score for this entry is not valid. The PROCHECK parameters for this entry could not be obtained, and poor results have been arbitrarily assumed.

PDB Entry: 4ls6
SPACI score: 0.56 (not valid)
AEROSPACI score: 0.56 (not valid)

Experiment type: XRAY
Resolution: 1.56
R-factor: 0.149
PCK1 PROCHECK Ramachandran: N/A
PCK2 PROCHECK Chi-1 angle: N/A
WCK1 WHAT_CHECK Packing: -1.194
WCK2 WHAT_CHECK Ramachandran: -1.361
WCK3 WHAT_CHECK Chi angles: 0.35
WCK4 WHAT_CHECK Backbone: 2.772

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).