Cover picture: Gonyautoxin 1,4 (GTX1,4), a C-11 sulfated saxitoxin analogue, docked in a molecular model of the voltage-gated Na⁺ channel outer vestibule. The C-11 sulfate is positioned superficially between domains III and IV, compatible with energetic localization of this group by mutant cycle analysis. The N1-OH group lies closest to domain I near the selectivity filter, and the 7,8,9 guanidinium group points toward the selectivity filter. These interactions fix the orientation of GTX1,4 with respect to the channel pore. GTX1,4 is shown in CPK format. Ribbons demonstrate the channel backbone. Carbon is shown as green, oxygen red, nitrogen blue, sulfur yellow, and hydrogen white. A, topview; B, side view of the outer vestibule. The domain I P-loop has been removed for clarity. See the article by Choudhary et al. on p. 912.