Table 1. Rate Constants for OBS Peptide Binding to OmpF^a.

	OBS12–18 from the periplasmic side	OBS254–63 from the extracellular side
k1 (106 M–1 s–1)	9.6 ± 0.60	4.0 ± 0.60
k2 (106 M–1 s–1)	6.1 ± 0.42	2.2 ± 0.64
k3 (106 M–1 s–1)	3.2 ± 0.25	0.97 ± 0.50b
k–1 (s–1)	43 ± 1.5	1.3 ± 0.10 × 104
k–2 (s–1)	78 ± 3.9	2.5 ± 0.34 × 104
k–3 (s–1)	111 ± 6.6	3.2 ± 0.47 × 104
Kd (μM)c	13 ± 1.0	11 ± 2.0 × 103

^aThe values are estimates at 0 mV obtained by extrapolation (Figure 1). Each rate constant and its standard deviation were determined from at least three independent experiments. Each experiment generated thousands of reversible binding events unless otherwise stated.

^bDue to fewer events in which all three subunits were occluded (<100) in the case of OBS2_54–63, the error in k₃ is relatively large compared to those for the other rate constants.

^cK_d values for a single OmpF subunit were statistically corrected by using the mean association and dissociation rate constants.