TABLE 2.

Kinetic constants for the short occupied states

PEG MW	f1 fraction of events	kon−1exp (M−1s−1) × 10−4	kon−1corr (M−1s−1) × 10−4	koff−1exp (s−1) × 10−4	koff−1corr (s−1) × 10−4	Kf−1exp (M−1)	Kf−1corr (M−1)
0.94	0.86 ± 0.05	20 ± 3	24 ± 1	4.6 ± 0.5	4.6 ± 0.5	4.3 ± 0.7	5.2 ± 0.8
2.0	0.85 ± 0.05	7.1 ± 1.9	8.7 ± 0.8	5.4 ± 0.6	5.4 ± 0.7	1.3 ± 0.2	1.6 ± 0.4
3.1	0.84 ± 0.05	0.71 ± 0.09	0.86 ± 0.11	4.4 ± 0.6	4.4 ± 0.7	0.16 ± 0.04	0.19 ± 0.04
4.2	0.84 ± 0.04	0.29 ± 0.04	0.36 ± 0.06	4.6 ± 0.5	4.6 ± 0.5	0.064 ± 0.012	0.080 ± 0.017
4.6	0.84 ± 0.05	0.28 ± 0.07	0.34 ± 0.09	4.1 ± 0.8	4.1 ± 0.8	0.065 ± 0.011	0.081 ± 0.016
6.0	0.88 ± 0.05	0.23 ± 0.04	0.28 ± 0.04	3.9 ± 0.5	4.0 ± 0.5	0.059 ± 0.010	0.069 ± 0.011

Values are the mean ± SD for at least four single-channel experiments. The PEGs were applied to the trans side of the bilayer. k_on−1 is the “on” rate constant for the short occupied states. k_off−1 is the “off” rate constant for the short occupied states. K_f−1 is the formation constant for the short occupied states. The “on” rate constants were obtained from the slope of a linear fit to 1/τ_on versus PEG concentration. The “off” rate constants were calculated as the reciprocal of the time constant τ_off, which was extracted from dwell time histograms. The superscript exp indicates that value was determined directly from a dwell time histogram and adjusted for promotion errors (see Materials and Methods). The superscript corr indicates the value was adjusted for missed events (see Online Supplement).