Table 3. Conventional Mutagenesis of Binding Site Residues^a.

mutation	EC50 (mM)	Hill	n	fold shift	Ω	ΔΔG (kcal/mol)
WT (T6′S)	0.0080 ± 0.0005	2.4 ± 0.3	27
R40A	1.1 ± 0.1	2.1 ± 0.1	17	140
R40E	no response
R59A	no response
R59E	no response
Y206A	no response
Y206F	0.10 ± 0.01	2.6 ± 0.3	14	13
T203A	0.64 ± 0.01	2.3 ± 0.1	19	80
T203A/Y206F	0.21 ± 0.01	2.2 ± 0.1	18	26	1/37	2.1
Q174A	0.11 ± 0.01	2.4 ± 0.2	14	14
N202A	0.010 ± 0.001	3.3 ± 0.2	16	1.25
Q174A/Y206F	0.92 ± 0.04	2.2 ± 0.2	13	115	0.67	0.23
Y156A	no response
Y156F	6.4 ± 0.4	1.6 ± 0.1	17	800
S126A	4.7 ± 0.1	2.5 ± 0.1	22	590
S126A/Y156F	no response

^aAll mutants have the T6′S background mutation.