Structural basis for voltage-sensor trapping of the cardiac sodium channel by a deathstalker scorpion toxin

The α-toxin LqhIII from the deathstalker scorpion inhibits fast inactivation of cardiac NaV1.5 channels. Here authors reveal the cryo-EM structure of LqhIII bound to NaV1.5 which shows that LqhIII traps the gating charges of the S4 segment in a unique intermediate-activated state and explains why LqhIII slows inactivation of NaV channels but does not open them.