Table 2.

Kinetic parameters of Trp fluorescence and ²²Na⁺ binding on WT BetP and mutants

		Trp Fluorescence			22Na binding
	Site	Apparent Kd (mM)	Bmax (ΔF/F)	n (Hill coefficient)	Apparent Kd (mM)	n (Hill coefficient)
WT		118 ± 3.9	0.89 ± 0.02	1.9 ± 0.1	53.3 ± 2.1	2.0 ± 0.2
S468A	Na2	871 ± 113†	0.16 ± 0.05	1.1 ± 0.3	147.5 ± 19†	1.0 ± 0.1
T467A/S468A	Na2	BD	BD	BD	BD	BD
T246L	Na1′	305 ± 28	0.36 ± 0.02	1.9 ± 0.2	167.7 ± 15.5	1.9 ± 0.2
T246L/T250A	Na1′	986 ± 335†	0.07 ± 0.03	2.4 ± 0.8	554.8 ± 35.8†	1.4 ± 0.1
S376A	—	191 ± 17	0.72 ± 0.05	1.9 ± 0.2	97.7 ± 5.8	1.8 ± 0.2
W101A/T351A	‡	153.4 ± 23	0.12 ± 0.01	2.0 ± 0.4	59.2 ± 1.5	1.9 ± 0.1

BD, below detection.

^†Saturation not reached, precluding reliable fitting of the data.

^‡Mutations in the trimer interface.