Fig. 1: Electrophysiological characterization and overall structure of rNaV1.5c with BTX-B.

a Chemical structure of BTX. b. Chemical structure of BTX-B. c Sodium current of rNaV1.5c in the absence (black) and the presence of 10 μM BTX-B (red). d Plots of conductance/voltage (G/V) relationship for rNaV1.5c in the absence (black) and the presence of 10 μM BTX-B (red). Data are presented as mean values ± SEM with n = 7 cells. e Cryo-EM density of BTX-B bound rNaV1.5c colored by local resolution (side bar). f Structure of BTX-B bound rNaV1.5c. Each domain is represented in different colors (NTD—dark purple, DI—dark blue, DII—dark green, DIII—dark yellow, DIV—dark red, DIII-DIV linker—orange). Glycosylation sites and lipids are shown as sticks in fandango and bright yellow, respectively.