Table 1. Kinetics of the transitions between IF and OF conformations.

Condition	tIF (s)	tOF (s)
WT, 5 mM ATP	16.1 ± 2.2	28.8 ± 4.8
WT, 5 mM ATP + 10 µM LTC4	4.7 ± 0.8	30.8 ± 5.2
E1454Q, 5 mM ATP + 10 µM LTC4	7.7 ± 1.5	31.7 ± 5.5

Shown are the average lifetimes (mean ± SEM) of the composite IF state and the OF state for WT and E1454Q MRP1 with indicated ATP and substrate concentrations. The effect of dye photobleaching on the apparent IF/OF lifetime has been corrected for.