Amino acid sequences of Ci-KCNQ1 and human KCNQ1 (hKCNQ1) are aligned for comparison. Same and similar amino acid residues are marked with asterisks and dots, respectively. Transmembrane regions (S1–S6) are boxed in green. The S5-P connector and pore helix are underlined. Red and blue arrowheads indicate the mutated amino acid residues in this study.