Fig. 6: Functional mapping: the dynamic range of NaCT is determined by residues of the H4c/H6b regulatory array.

A–D Different NaCT structure representations show the functional map of the H4c/H6b domain (light green—full function, dark green—less than 25% loss-of-function, orange—more than 50% loss-of-function, red—more than 75% loss-of-function). E Summary of NaCT currents monitored in Xenopus oocytes injected with H4c/H6b mutants. The color codes of the columns was used for functional mapping in all NaCT structural representations. F The currents shown in (E) are re-plotted by current intensity (high to low order) to demonstrate the full dynamic range determined by H4c/H6b residues (inset—ribbon representation of H4c/H6b functional mapping). The results in Fig. 2B and D, Supplementary Figs. 5A, 8B and E, and  9B and D, are presented in Fig. 6E and F.