PMC

a) Macroscopic currents for the KcsA G77dA channel elicited at +80 mV by a rapid change in pH. b) The ion binding sites in the selectivity filter of the KcsA G77dA channel (PDB: 2IH3). Two opposite subunits are shown as sticks. Side chains of V76 and Y78 are omitted for clarity. The F_o-F_c electron density (KcsA residues 75–79, K⁺ ions, and lipid omitted) along the central axis of the selectivity filter contoured at 3.0 σ is shown. The one-dimensional plot of the electron density is shown on the right. c) Macroscopic currents for the KcsA V76ester+ G77dA channel elicited at +80 mV by a rapid change in pH. d) Recovery from inactivation in the G77dA (black triangles) and the V76ester+G77dA channels (red squares). Data points represent the mean ± SD from 3–6 patches. The solid lines are single exponential fits. e) Structure of the selectivity filter of the V76ester+G77dA channel. The 2F_o-F_c electron density map contoured at 2.8 σ is shown with residues 71–80 of the channel represented as sticks and K⁺ ions in the filter represented as spheres. f) Superposition of residues 71–80 of the V76ester+G77dA channel (red) with the G77dA (blue, PDB: 2IH3) and the wild type channels (grey, PDB: 1K4C). g) The ion binding sites in the selectivity filter of the V76ester+G77dA KcsA channel. The F_o-F_c electron density (KcsA residues 75–79, K⁺ ions, and lipid omitted) contoured at 3.0 σ is shown along the central axis of the selectivity filter. The one-dimensional plot of the electron density is shown on the right.

Processed single channel data. a) Black is the filtered data (median filter) and grey is the recorded current. Filter removed the high frequency noise without smoothing the transition edges. b) Black is the rectangular pulse representation of the recorded data (grey). c) Summation of the rectangular-pulse representation of channel currents (black) compared to the summation of recorded single channel currents (grey).

Pre-processing if EEG data using de-noise and Fourier filter. (a) Collection of raw EEG data of channel 1–16 for 420s–422s. (b) Collection of raw EEG data of channel 17–31 for 420s–422s. (c) Fourier fitting data of channel 1–16 for 420s–422s. (d) Fourier fitting data of channel 17–31 for 420s–422s.

a) Macroscopic currents for the KcsA T75G channels elicited at +80 mV by a rapid change in pH. b) Recovery from inactivation in the KcsA T75G (blue open circles), V76 ester (red triangles), and wild type channels (black closed circles). Data points represent the mean ± SD from 3–7 patches and the solid lines are single exponential fits. Data for the V76ester and the wild type channel are from and respectively. c) Structure of the selectivity filter of the KcsA T75G channel. The 2F_o-F_c electron density map contoured at 2.5 σ is shown with residues 71–80 of the channel represented as sticks and K⁺ ions in the filter represented as spheres. d) Superposition of residues 71–80 of the KcsA T75G (red) and the wild type channel (blue). e) The ion binding sites in the selectivity filter of the T75G channel. The F_o-F_c electron density (KcsA residues 75–79, K⁺ ions, and lipid omitted) along the central axis of the selectivity filter contoured at 3.0 σ is shown. The one-dimensional plot of the electron density for the T75G (red) and the wild type (black) channel is shown on the right.