Fig. 2.

Introduction of cysteine mutations into Hv1. (a) The positions that were mutated to cysteine are indicated by filled circles on the voltage-sensor structure of the Kv 1.2–2.1 paddle chimera (Protein Data Bank ID code 2R9R). The S1–S2 loop from the paddle chimera was replaced with a shorter loop to match the length of Hv1. (b) The amino acid sequence of Hv1 excluding the N-terminal acid-rich and proline-rich region. Predicted transmembrane regions, based on the structure of the paddle chimera and hydropathy, are highlighted in gray. Residues mutated to cysteine are colored red. C107 and C249 are natural cysteines. The region corresponding to the coiled coil was calculated by the program COIL (24).