TABLE 2

Affinity (log K_D values) of β-adrenoceptor ligands for the β2-WT and β1-WT and receptors containing whole TM or EL changes (see Table 1 for details) in stable cell lines

The K_D values of [³H]CGP 12177 (measured from saturation binding) and the receptor expression levels are also given. The values are mean ± S.E.M. for n separate experiments.

	K_D [³H]CGP 12177	n	Protein	Log K_D Salmeterol	n	Log K_D Salbutamol	n	Log K_D Formoterol	n	Log K_D Fenoterol	n
			fmol/mg
β2-WT	0.21 ± 0.02	29	279 ± 20	−8.95 ± 0.05	30	−5.94 ± 0.03	33	−8.29 ± 0.03	32	−6.80 ± 0.02	30
β2-N	0.29 ± 0.04	9	389 ± 42	−9.14 ± 0.05	10	−5.90 ± 0.03	11	−8.25 ± 0.05	10	−6.86 ± 0.03	10
β2-EL1	0.36 ± 0.02	9	946 ± 97	−8.99 ± 0.04	10	−5.84 ± 0.03	11	−8.12 ± 0.06	10	−6.61 ± 0.02^*	10
β2-EL2	0.30 ± 0.01	9	516 ± 35	−8.28 ± 0.06 ^*	10	−5.60 ± 0.04^*	11	−7.74 ± 0.06^*	10	−6.37 ± 0.03^*	9
β2-EL3	0.28 ± 0.02	9	778 ± 63	−6.74 ± 0.03^*^,#	10	−5.68 ± 0.03^*	11	−7.89 ± 0.05^*	10	−6.51 ± 0.03^*	10
β2-TM1	0.17 ± 0.06	15	138 ± 8	−9.11 ± 0.10	8	−5.83 ± 0.04	9	−8.18 ± 0.04	8	−6.82 ± 0.03	9
β2-TM2	0.22 ± 0.02	11	405 ± 41	−8.57 ± 0.08^*	7	−5.76 ± 0.03	7	−8.27 ± 0.09	7	−7.16 ± 0.10^*	7
β2-TM3	0.34 ± 0.03	10	1037 ± 113	−8.84 ± 0.05	8	−5.77 ± 0.07	8	−7.66 ± 0.05^*	8	−6.15 ± 0.04^*	7
β2-TM4	0.25 ± 0.03	11	458 ± 64	−8.96 ± 0.03	7	−5.97 ± 0.07	7	−8.30 ± 0.03	7	−6.87 ± 0.02	8
β2-TM5	0.32 ± 0.03	10	849 ± 83	−9.00 ± 0.05	7	−5.84 ± 0.03	8	−8.05 ± 0.07	8	−6.48 ± 0.03^*	6
β2-TM6	0.75 ± 0.06	9	728 ± 58	−7.37 ± 0.03^*	7	−5.89 ± 0.08	7	−8.06 ± 0.07	8	−6.65 ± 0.04	7
β2-TM7	0.14 ± 0.02	14	67 ± 5	−7.57 ± 0.06^*	8	−5.83 ± 0.06	10	−7.57 ± 0.04^*	9	−6.16 ± 0.03^*	10
β1-WT	0.32 ± 0.02	28	534 ± 33	−5.80 ± 0.02	27	−4.80 ± 0.02	27	−6.02 ± 0.02	25	−5.09 ± 0.03	27
β1-N	0.50 ± 0.02	6	1309 ± 126	−5.60 ± 0.01^*	7	−4.71 ± 0.02	7	−5.90 ± 0.02	6	−4.95 ± 0.05	7
β1-EL1	0.31 ± 0.01	9	497 ± 39	−5.69 ± 0.05	7	−4.74 ± 0.03	7	−6.10 ± 0.04	6	−5.14 ± 0.02	7
β1-EL2	0.58 ± 0.03	9	1100 ± 111	−5.72 ± 0.03	7	−4.74 ± 0.04	7	−6.08 ± 0.04	6	−5.13 ± 0.04	7
β1-EL3	0.54 ± 0.04	9	384 ± 30	−6.25 ± 0.06^*	7	−5.01 ± 0.03^*	7	−6.35 ± 0.06^*	6	−5.43 ± 0.06^*	7
β1-TM1	0.30 ± 0.02	11	372 ± 47	−5.75 ± 0.05	12	−4.74 ± 0.03	12	−6.03 ± 0.03	8	−5.05 ± 0.07	8
β1-TM2	0.26 ± 0.03	10	567 ± 58	−5.50 ± 0.03^*	12	−5.09 ± 0.02^*	12	−6.56 ± 0.05^*	8	−5.54 ± 0.06^*	8
β1-TM3	0.48 ± 0.03	10	1994 ± 214	−5.73 ± 0.02	12	−4.67 ± 0.03	12	−5.95 ± 0.03	8	−5.06 ± 0.07	8
β1-TM4	0.26 ± 0.02	12	233 ± 18	−5.91 ± 0.04	12	−4.84 ± 0.03	12	−6.31 ± 0.05^*	8	−5.06 ± 0.08	8
β1-TM5	0.25 ± 0.02	12	359 ± 30	−5.82 ± 0.04	11	−4.86 ± 0.04	12	−6.17 ± 0.03	8	−5.20 ± 0.05	8
β1-TM6	0.29 ± 0.01	19	1207 ± 100	−5.89 ± 0.02	18	−5.01 ± 0.03^*	18	−6.37 ± 0.03^*	7	−5.45 ± 0.08^*	7
β1-TM7	0.57 ± 0.04	9	2078 ± 133	−6.44 ± 0.02^*	17	−5.42 ± 0.02^*	18	−6.93 ± 0.05^*	7	−5.86 ± 0.09^*	7

↵* P < 0.001. One-way analysis of variance with post hoc Newman-Keuls comparing values from the mutant receptors with those obtained from the β2-WT or the β1-WT. Thus, the log K_D for salmeterol at the β2-EL2 is different from that obtained from the β2-WT with P < 0.001. Likewise, the log K_D for salmeterol at the β1-EL3 is different from that obtained from the β1-WT with P < 0.001; ^#P < 0.001. One-way analysis of variance with post hoc Newman-Keuls comparing each value with all other values in this set. Thus, the log K_D for salmeterol at β2-EL3 is different from that obtained for β2-WT, β2-N, β2-EL1, β2-EL2, β2-TM1, β2-TM2, β2-TM3, β2-TM4, β2-TM5, β2-TM6, and β2-TM7 with P < 0.001 in all cases.