TABLE 1.

Analysis of the rate constant, k_s, for transitions from the fully open state to signature-events

	No. sweeps	Rate constant for transition to signature-event, ks (s−1)
Normal buffer	13	0.04
100 mM βME	12	<3.1 × 10−3

The number of analyzed suction sweeps and k_s are given for V15C channel in regular buffer and with added 100 mM βME. The “less than” sign in the second row indicates that we observed no definitive signature-events in the V15C traces when reducing agent was added to the buffer. Thus the reported value serves only as a “less than” estimate.