XB-IMG-121796
Xenbase Image ID: 121796
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Figure 3. Multiple amino termini are required to slow deactivation in the HERG channel. (A) Tail currents from S620T Î2-354 channels show progressive slowing in solutions of increasing H16 peptide concentration. From top to bottom, the concentrations are 0, 100, 250, 500, 750, and 1,000 μM. (B) Doseâresponse curve plotted as a fractional slowing of deactivation rate [Î(1/Ï)/Î(1/Ï)max] against peptide concentration (n = 3 for each peptide concentration up to 1 mM, n = 2 for 5 mM). Ï is the time constant of the dominant fast component, which contributes >90% of the deactivating current. Fitting the data to the Hill equation [ln(1 â y)/y] = âN(lnK â ln[peptide]) yielded a Hill coefficient of 2.2 ± 0.1, indicating possible cooperative interactions among at least three amino termini. (C) High concentrations (5 mM) of peptide blocked the current (top), but caused no further slowing of deactivation (scaled currents, bottom). Image published in: Wang J et al. (2000) © 2000 The Rockefeller University Press. Creative Commons Attribution-NonCommercial-ShareAlike license Larger Image Printer Friendly View |