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. 1999 Dec 7;96(25):14336–14341. doi: 10.1073/pnas.96.25.14336

Figure 3.

Figure 3

Single-channel recordings from three Vpu constructs: Vpu (Left), Vpu2–51 (Center), and Vpu28–81 (Right) in symmetric 0.5 M KCl (A) or 0.5 M NaCl (B) and 10 mM Hepes (pH 7.4). Short segments of continuous recordings were selected to illustrate the occurrence of the 22-pS (K+) and 29-pS (Na+) channel for full-length Vpu and the 26-pS (K+) and 23-pS (Na+) channel for truncated Vpu2–51. The cytoplasmic domain Vpu28–81 does not form ion channels. Note the occurrence of only stray, erratic fluctuations in membrane current produced by Vpu28–81 in contrast with the square events produced by Vpu and Vpu2–51. The currents of the closed (C) and open (O) states are indicated. Upward deflection indicates channel opening. Corresponding cumulative current histograms and Gaussian fits for the primary conductances generated from continuous segments of recordings lasting several minutes. (A) For Vpu, the probability of the channel being open (Po) is 0.56 recorded at 85 mV. For Vpu2–51, Po = 0.76 recorded at 100 mV. (B) For Vpu, Po = 0.75 recorded at 50 mV; for Vpu2–51, Po = 0.56 recorded at 50 mV.