Figure 6. I890 is a conserved aminoacid, located in the intramembrane pore region of Na_v1.5 DII.

(A) Sequence alignment of the pore modules of human Na_v1.5 channel (DII) and Na_v Ab. Identical aminoacids are highlighted in grey. Isoleucine-890 is marked with a dark box. Similar aminoacids are included inside light boxes and dots identify insertions (lower panel). Sequence alignment of human voltage-gated sodium channel α-subunit family members and of Na_v1.5 channels of different species, upper and middle panels, respectively. The position of the first amino acid of each sequence is indicated on the left side, and the reference for each protein according to Uniprot is shown at the right side. (B) Partial view of the CPHmodel showing the pore module of DII of Na_v1.5 channel (in green), based on the coordinates of Na_v Ab channel (in red). I890_Nav1.5 and T169_NavAb are located in the middle of P1-helix and highlighted in blue and magenta, respectively. View from the interior side of the pore. (C) Na_v1.5 channel scheme. The relative position of the I890T mutation in the S5–S6 loop of domain II (DII) is indicated with an arrow.