Table 1.

Single-channel characteristics of KvLm homotetramers and heterotetramers

Tetramer	Conductance, pS	Open-state lifetime, ms*	Open-state occupancy	Closed-state occupancy	Median burst duration, ms	Bursts per second
FL4	73 ± 7	1.9 ± 0.3	4.0 ± 0.4 × 10-2	0.9 ± 0.1	16 ± 3	5 ± 1
FL3PM1	93 ± 7	1.7 ± 0.3	5.0 ± 0.5 × 10-2	0.7 ± 0.1	11 ± 3	13 ± 2
FL2PM2	73 ± 2	0.3 ± 0.2†	2 ± 2 × 10-4	<  < 0.1†	NA	NA
FL1PM3	93 ± 7	1.5 ± 0.3	2 ± 1 × 10-3	0.9 ± 0.1	5 ± 0.4	0.4 ± 0.3
PM4	113 ± 7	1.4 ± 0.3	1.0 ± 0.5 × 10-3	0.9 ± 0.1	4 ± 0.2	0.7 ± 0.3

Single-channel properties recorded at V = +150 mV for homotetrameric and heterotetrameric assemblies composed of KvLm-FL and KvLm-PM subunits.

^*It is worth noting that fittings of open time distributions of all assemblies but FL₄ miss a short-lived component (< 1 ms) (Figs. S2 and S3). The conjecture that all four sensors stabilize the open state is in line with these observations notwithstanding the limitation of our recording system to resolve such brief openings.

^†For FL₂PM₂, open- and closed-state lifetimes are estimates given that the time resolution of the recording prevents rigorous determinations. Open and closed state occupancies do not add up to 1 because the channel resides in a subconductance state(s) for a fraction of the time.