On the ΔC26 background, T171A mutation restores bursting single-channel kinetics, whereas G334D mutation preserves spiking single- channel kinetics. (A) Kir6.2∷T171A/ΔC26 in the absence of SUR1, slow time scale, with a segment of the recording expanded on a fast time scale as indicated. On average, the 5,000 μM ATP inhibits one of two channels. Notice that the T171A mutation reverts the spiking single-channel gating kinetics of the ΔC26 parent channel to the long bursts of rapid successive openings similar to the wild-type KATP channel (see Fig. 5B). (B) Kir6.2∷G334D/ΔC26 in the absence of SUR1, slow time scale, with a segment of the recording expanded on a fast time scale as indicated. Notice that the channels retain the spiking single-channel gating kinetics of the ΔC26 parent channel. (See Fig. 5A). All currents were recorded at −80 mV.