Fig.5.

Sequence alignment for the S3 through S4 paddle region of voltage-activated cation channels.

Horizontal cylinders indicate the approximate positions of S3 (divided into S3_a and S3_b) and S4 helices. Numbers indicate the residue positions within the K_v2.1 channel and shading indicates similarity to K_v2.1. For the Shaker K_v channel 13 residues have been omitted for alignment purposes and their position marked by the asterisk. Red highlighting indicates residues whose mutations cause pronounced changes in the binding affinity of gating modifier toxins (see text for details).