Charge differences between pH-sensitive and pH-insensitive ASICs.

<p>(A) Closed (desensitised) chicken ASIC1a structure and rat ASIC4 model, with electrostatic contours plotted (for physiological pH), at a relatively low contour (+/- kT/e, red is negative and blue shows positive potential). (B) The potential fields of (A) are differenced at a much higher level (+/- 16 kT/e) to identify the regions of most interest, which appear as the red mesh contour, indicating more negative contours in ASIC1a. These contours coincide with the groups indicated in the predictions of pH-sensitivity for ASIC1a (green surface) shown in Figs <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0125293#pone.0125293.g004" target="_blank">4C</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0125293#pone.0125293.g006" target="_blank">6A</a>. No calcium ions were included in these calculations.