Table 1.

Numerical key to H_V1 in species verified by heterologous expression

Species are indicated by one- or two-letter abbreviations: h, human; m, mouse; Ci, Ciona intestinalis; Np, Nicoletia phytophila; Sp, Strongylocentrotus purpuratus; k, Karlodinium veneficum; Pt, Phaeodactylum tricornutum; Cb, Coccolithus braarudii; Eh, Emiliania huxleyi. HG, hydrophobic gasket residues (gray); Sel, selectivity filter (yellow). Zn²⁺, one of the two Zn²⁺-binding His (in some species). Green-shaded residues sense voltage. Okamura et al. (2015) propose a slightly different hydrophobic plug based on the mH_V1 crystal structure: F146, M147, L150, and F178. Several alignments of the S4 helix have been produced, which result in shifts in the register of the basic residues. Kv1.2 is human, NCBI Reference Sequence accession no. NP_004965.1; Shaker is UniProt/Swiss-Prot accession no. P08510.3.