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Figure 1.
Figure 1. a−h, Single-channel recordings from recombinant M2
peptides in lipid bilayers. The currents were recorded at
constant voltage in symmetric 500 mM NaCl or KCl supplemented
with 1 mM CaCl[2], 5 mM HEPES pH 7.4. The currents of closed (C)
and open (O) states are indicated by the solid lines. Dotted
lines define the range set to discriminate the transitions
between states, based on signal-to-noise measurements. The AChR
M2 traces show bursts of channel activity with single-channel
conductances of 37  2
pS in 500 mM NaCl at 50 mV (a), and 38 2
pS in 500 mM KCl at 100 mV (c). For NMDAR M2, single-channel
conductances of 20 2
pS NaCl (e), and 40 3
pS in 500 mM KCl (g) were measured. Both NMDAR traces were
recorded at 100 mV. In the corresponding histograms for AChR M2
( b, d) and for NMDAR M2 (f, h), the Gaussian fits of the data
in NaCl (b, f) or KCl (d, h) indicate the respective
probabilities of the open- (O) versus closed- (C) channel states.
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