FIGURE 1.

Conserved Trp residue within the S4 segment. A, alignment of the amino acid sequences of the S4 segment in the Hv family and other voltage-gated channels. The conserved Trp at the middle of S4 is highlighted in gray, and another aromatic residue, Phe, is highlighted in light gray. Conserved Arg, a voltage sensor, is highlighted in blue. B, representative current traces recorded from wild-type Hv (WT) and the NA-mutant (W257I/F260A). Currents were recorded with step pulses in the range of −60 to +120 mV for 100 ms with 10-mV increments. Red traces depict the currents recorded at +100 mV.