Table 1. Estimates of BMS-986187 Binding Affinity (K_B), and the Cooperativity Parameter αβ Which Incorporates Modulatory Effects on Orthosteric Agonist Affinity (α) and Efficacy (β), at the WT or Mutant δ-opioid Receptors^a.

mutant	pKB	log αβ	log α	log β
WT	6.24 ± 0.20	1.08 ± 0.09	= 0	1.08 ± 0.09
Y56(1.39)A	5.64 ± 0.25	1.28 ± 0.31	= 0 (NC)	1.28 ± 0.31
Q105(2.60)A	5.09 ± 0.30*	2.08 ± 0.67	= 0	2.08 ± 0.67
K108(2.63)A	5.34 ± 0.40	1.77 ± 0.41	= 0	1.77 ± 0.41
K108(2.63)N	5.70 ± 0.34	0.55 ± 0.32*	= 0	0.55 ± 0.32*
Y109(2.64)A	4.93 ± 0.77	2.22 ± 0.72	= 0	2.22 ± 0.72
Y109(2.64)I	4.82 ± 0.53**	2.46 ± 0.36	0.54 ± 0.21*	1.92 ± 0.42**
W284(6.58)K	5.49 ± 0.19*	1.36 ± 0.24	= 0 (NC)	1.36 ± 0.24
L300(7.35)W	4.74 ± 0.11***	2.14 ± 0.12**	= 0 (NC)	2.14 ± 0.12**
H301(7.36)R	5.27 ± 0.31	1.65 ± 0.34	0.90 ± 0.29**	0.75 ± 0.45
H301(7.36)Y	4.95 ± 0.30***	1.96 ± 0.36	0.24 ± 0.27	1.72 ± 0.45

^aParameters are obtained by operational model fitting of data from [³H]diprenorphine binding and pERK phosphorylation assays. Equal sign before a value indicates that it was constrained during the fitting of the operational model; “NC” indicates that the value could not be obtained from the binding studies. Statistical significance levels from Dunnet’s test p values are indicated as stars (respectively p < 0.05, 0.01, 0.001).