Fig. 5.

The S4 helix. (A) Stereo side view of MlotiK1 and Kv1.2 S1–S4 domains superposed via S2 and S1. 3₁₀ regions in S4 of MlotiK1 and Kv1.2 are shown in red and cyan, respectively. Other TMs are represented by brown ribbons. S4 residues discussed in the text are labeled. (B) Extracellular view of S1–S4 domains from MlotiK1 and Kv1.2 superposed via S2 and S1. 3₁₀ regions in S4 as in A. Other helical regions are in white ribbons. Kv1.2 R1, R2, R3, R4, K5, and R6 and equivalent MlotiK1 Cα atoms are shown as blue and black spheres, respectively. (C) Surface representation of MlotiK1 S1–S4 domain. S4 is shown as a red ribbon, with residues equivalent to R2, R3, R4, K5, and R6 shown as sticks. Protein regions from S1 to S3 are shown as gray surface representations. S1, S2, and S3 helices are shown as green ribbons inside the surface. (D) Same as in C but viewed from the extracellular side.