Mu-thomitoxin-Hme1c

UniProtKB accession:  C0HJK5

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UniProtKB description:  Gating-modifier toxin that inhibits mammalian and insect voltage-gated sodium channels. It shifts the voltage dependence of channel activation to more positive voltages. It shows potent activity on Nav1.4/SCN4A (IC(50)=103 nM), Nav1.5/SCN5A (IC(50)=268 nM) and Para/DmNav1 (IC(50)=555 nM) and lower activities on Nav1.2/SCN2A (IC(50)=1447 nM) and Nav1.6/SCN8A (IC(50)=3504 nM) (PubMed:25352595). In addition, at a concentration of 1 uM, the toxin inhibits 90-100% of sodium current through Nav1.2/SCN2A, Nav1.4/SCN4A, Nav1.5/SCN5A, Nav1.6/SCN8A and Para/DmNav1 channels, when the voltage of maximal activation of the channel in control conditions is applied (Ref.1). It binds to the S3-S4 helix-loop-helix motif in the voltage-sensing domain of repeat 1 (shown on hNav1.4/SCN4A) (PubMed:29636418). The toxin is amphiphilic and binds to both neutral and negatively charged lipid vesicles with high affinity (PubMed:29636418, PubMed:25352595). The hydrophobic face lies on the opposite side to the hydrophobic faces of classical gating modifiers (PubMed:25352595).