Table 1. Refinement statistics for the three P-glycoprotein crystallographic models [15–17].

Crystallographic refinement statistic	3G5U	4M1M	4KSB
Resolution range high (Å)	3.8	3.8	3.8
Resolution range low (Å)	19.98	24.89	92.56
Number of reflections	41131	41385	21753
R value (working set)	0.306	0.267	0.357
Free R value	0.346	0.267	0.357
Free R value test set	4203	4203	1062
Estimated coordinate error (maximum likelihood)	-	0.46	0.82
Phase error (degrees, maximum-likelihood)	-	27.47	38.35
Luzzati plot	0.86	-	-
SigmaA	0.82	-	-
Ramachandran outliers (asymmetric unit)	594	92	79
Atomic coordinates in asymmetric unit	18352	18378	9171