XB-IMG-124087
Xenbase Image ID: 124087
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Figure 4. Macroscopic rectification of the E363Q mutant reflects voltage gating, not asymmetric ion conduction. (A) Single-channel i-V curve (mean ± SEM; n = 4â7) of the E363Q mutant (filled circles) and the (arbitrarily scaled) macroscopic I-V curve (mean ± SEM; n = 5) in the presence of 2 mM cGMP (open circles). The dotted line through the single-channel data points is hand drawn. (B) Single-channel current amplitude of the E363Q mutant (mean ± SEM; n = 5â20) at 120 or â120 mV and in the presence or absence of 0.1 mM of extracellular Mg2+. *, P < 0.001 (one-way ANOVA). (CâF) Representative single-channel currents of the E363Q mutant recorded at 120 mV (C and D) or â120 mV (E and F) and in the absence (C and E) or presence (D and F) of 0.1 mM of extracellular Mg2+; each trace was recorded from a separate inside-out patch. (GâJ) Longer-duration macroscopic current traces recorded in 2 mM cGMP (G and H) from membrane patches of two oocytes expressing different densities of E363Q channels. Traces at â200 mV were magnified to show individual channel activity; the control traces recorded from the same patches at â200 mV and in the absence of cGMP are shown below (I and J). Image published in: Martínez-François JR et al. (2009) © 2009 Martínez-François et al. Creative Commons Attribution-NonCommercial-ShareAlike license Larger Image Printer Friendly View |