Evidence 1
Activity
Activity
Neurotoxin
FUNCTION: Selective antagonist of neuronal tetrodotoxin (TTX)-sensitive voltage-gated sodium channels (IC(50)=1270 nM on Nav1.1/SCN1A, 270 nM on Nav1.2/SCN2A, 491 nM on Nav1.3/SCN3A and 232 nM on Nav1.7/SCN9A). This toxin suppress Nav1.7 current amplitude without significantly altering the activation, inactivation, and repriming kinetics. Short extreme depolarizations partially activate the toxin-bound channel, indicating voltage-dependent inhibition of this toxin. This toxin increases the deactivation of the Nav1.7 current after extreme depolarizations. The toxin-Nav1.7 complex is gradually dissociated upon prolonged strong depolarizations in a voltage-dependent manner, and the unbound toxin rebinds to Nav1.7 after a long repolarization. Moreover, analysis of chimeric channels showed that the DIIS3-S4 linker is critical for toxin binding to Nav1.7. These data are consistent with this toxin interacting with Nav1.7 site 4 and trapping the domain II voltage sensor in the closed state. {ECO:0000269|PubMed:23703613}.
Target
voltage-gated sodium channel (Nav)
Source & Reference
NA
UniProtKB/Swiss-Prot Tox-Prot
Other
Cyriopagopus hainanus (Chinese bird spider) (Haplopelma hainanum)
Neurotoxin
Presynaptic neurotoxin
Ion channel impairing toxin
Voltage-gated sodium channel impairing toxin
Selective antagonist of neuronal tetrodotoxin (TTX)-sensitive voltage-gated sodium channels (IC(50)=1270 nM on Nav1.1/SCN1A, 270 nM on Nav1.2/SCN2A, 491 nM on Nav1.3/SCN3A and 232 nM on Nav1.7/SCN9A). This toxin suppress Nav1.7 current amplitude without significantly altering the activation, inactivation, and repriming kinetics.
Hainantoxin-III 12 (HnTx-III.12) (Hainantoxin-3.12) (Mu-theraphotoxin-Hhn2a) (Mu-TRTX-Hhn2a) (Peptide F7-18.76)
spider
Neurotoxin 10 (Hwtx-1) family, 15 (Hntx-3) subfamily
Evidence at protein level
Amidation
Direct protein sequencing
Disulfide bond
Ion channel impairing toxin
Knottin
Neurotoxin
Presynaptic neurotoxin
Secreted
Signal
Toxin
Voltage-gated sodium channel impairing toxin
TISSUE SPECIFICITY: Expressed by the venom gland. {ECO:0000305|PubMed:14512091, ECO:0000305|PubMed:23703613}.