TABLE 2.

ACh binding to the C conformation k₊ indicates single site association rate constant; k_– indicates single site dissociation rate constant; K_d indicates equilibrium dissociation constant (= k_–/k₊) to the C conformation; ΔΔG, free energy, = 0.59·ln(K_d^mut/K_d^WT). A positive value indicates that the mutation reduced the affinity of the C transmitter binding site for ACh.

Construct	Rate constant		Equilibrium constant
	k+	k–	Kd	Fold change	ΔΔG
	μm–1 s–1	s–1	μm		kcal mol–1
WTa	170	24,750	150a
εW55A	5	17,890	3740	25.3	+1.9
εW55E	11	17,950	1610	10.8	+1.4
εW55F	27	16,500	620	4.2	+0.8
εW55I	20	66,310	3320	22.4	+1.8
εW55V	27	30,640	1560	10.5	+1.4
εW55Y	37	10,460	280	1.9	+0.4
δW57A	6	26,770	4170	28.1	+1.9
δW57Fb	135	30,590	230	1.5	+0.2
δW57H	57	17,600	310	2.1	+0.4
δW57L	40	70,980	1730	11.7	+1.4
δW57R	21	15,570	750	5.0	+0.9
δW57V	27	17,160	470	3.2	+0.7
δW57Y	20	30,110	1510	10.2	+1.3

^aData are from Ref. 23

^bData are from Ref. 19