A sodium channel inhibitor ISTX-I with a novel structure provides a new hint at the evolutionary link between two toxin folds.

ABSTRACT: Members of arachnida, such as spiders and scorpions, commonly produce venom with specialized venom glands, paralyzing their prey with neurotoxins that specifically target ion channels. Two well-studied motifs, the disulfide-directed hairpin (DDH) and the inhibitor cystine knot motif (ICK), are both found in scorpion and spider toxins. As arachnids, ticks inject a neurotoxin-containing cocktail from their salivary glands into the host to acquire a blood meal, but peptide toxins acting on ion channels have not been observed in ticks. Here, a new neurotoxin (ISTX-I) that acts on sodium channels was identified from the hard tick Ixodes scapularis and characterized. ISTX-I exhibits a potent inhibitory function with an IC50 of 1.6 μM for sodium channel Nav1.7 but not other sodium channel subtype

SUBMITTER: Rong M 

PROVIDER: S-EPMC4942781 | biostudies-literature | 2016 Jul

REPOSITORIES: biostudies-literature