Figure 3. Non-charged residues in S4 segment modulate temperature-sensitivity.

(A) Relative P_OV curves, at two temperatures (28°C, red and 8°C, blue) for hextuplet mutations in the S4 segment where six residues are simultaneously mutated to Ile (left), Met (middle) or Ala (right). (B) Relative P_OV curves, at two temperatures (28°C, red and 8°C, blue) for quadruplet mutations in the S4 segment where four residues are simultaneously mutated to Ile (left), Met (middle) or Ala (right). (C) Correlation of temperature dependent change in the median voltage of channel opening (ΔV_M) with the hydrophobicity of perturbations for the Top (left panel), Middle (middle panel) and Bottom (right panel) doublet mutations (see also Figs. S3). The color gradient is used to show the transition from heat (negative ΔV_M) to cold sensitivity (positive ΔV_M) for the spectrum of mutations. (D) Correlation of median voltage of channel opening (V_M) at 28°C with the hydrophobicity of perturbations for the Top (left panel), Middle (middle panel) and Bottom (right panel) doublet mutations. (E) Relative P_OV curves at two temperatures (28°C, red and 8°C, blue) for doublet Ser mutations.