TABLE 2.

Rate and equilibrium constants for αM3 mutant AChRs activated by 20 mM choline

	Opening rate constant (ko)		Closing rate constant (kc)		Equilibrium constant (Keq)
	Mean	SE	Mean	SE	Mean	SE	Keq ratio
Wt	120		1000		0.12
δS268V	141	19	53	6	2.66	0.47
αY277D (24′)+ δS268V	67	8	278	15	0.24	0.03	0.09
αY277L (24′) + δS268V	138	12	314	35	0.44	0.06	0.17
αY277S (24′) + δS268V	124	22	428	22	0.29	0.05	0.11
αY277T (24′) + δS268V	44	3	667	59	0.07	0.01	0.02
αY277H (24′) + δS268V	51	5	479	19	0.11	0.01	0.04
αY277F (24′)	448	47	853	40	0.53	0.06	4.38
αL279T (22′)	198	13	446	30	0.44	0.04	3.7
αL279I (22′)	120	3	1005	55	0.12	0.01	1
αL279W (22′)	488	131	26	2	18.77	5.24	156.41
αF280W (21′)	180	8	394	15	0.46	0.03	3.81
αV283A (18′)	165	11	549	33	0.30	0.03	2.5
αV283W (18′)	239	27	187	11	1.28	0.16	10.65
αV283Q (18′)	221	2	245	28	0.90	0.10	7.52
αI289A (12′)	89	3	1019	61	0.09	0.01	0.73
αI290W (11′)	151	16	568	108	0.27	0.06	2.22
αI290Q (11′)	91	7	1599	301	0.06	0.01	0.47
αI290A (11′)	87	1	1945	194	0.04	0.00	0.37
αV293W (8′)	89	12	945	51	0.09	0.01	0.78
αI294W (7′)	71	9	970	42	0.07	0.01	0.61
αN297W (4′)	95	11	1182	44	0.08	0.01	0.67
αN297M (4′)	70	9	897	50	0.08	0.01	0.65

Rate constants are s⁻¹ (mean of three patches). K_eq = k_o/k_c. The K_eq ratio is mutant/wt, except for the Y277 series, which is mutant/δS268V background. No correction was made for channel block by the agonist so the k_c values are approximately half of those of unblocked AChRs. Φ-values were not estimated for positions 4′, 7′, and 8′ because the range of K_eq values was less than fivefold.