2kyj

Structural highlights

Function

TXS2B_HORWA Affects the activity of both ryanodine-sensitive calcium-release channels RyR1 and RyR2 with high potency. At lower concentrations the toxin increases full openings of the RyRs, and at higher concentrations it inhibits full openings and induce openings to subconductance levels and reduces the number of full conductance openings. The different actions may be attributed to the toxins binding at different sites on the RyRs, with binding at a high-affinity site mediating the increase in full openings and the induction of subconductance states evoked upon binding to a lower-affinity site. Insect-selective toxin that provokes a dose-dependent contractile paralysis in crickets and blowfly larvae, followed by death.^{[1] [2]}

References

1. ↑ Smith JJ, Hill JM, Little MJ, Nicholson GM, King GF, Alewood PF. Unique scorpion toxin with a putative ancestral fold provides insight into evolution of the inhibitor cystine knot motif. Proc Natl Acad Sci U S A. 2011 Jun 28;108(26):10478-83. PMID:21670253 doi:10.1073/pnas.1103501108
2. ↑ Smith JJ, Vetter I, Lewis RJ, Peigneur S, Tytgat J, Lam A, Gallant EM, Beard NA, Alewood PF, Dulhunty AF. Multiple actions of phi-LITX-Lw1a on ryanodine receptors reveal a functional link between scorpion DDH and ICK toxins. Proc Natl Acad Sci U S A. 2013 May 28;110(22):8906-11. PMID:23671114 doi:10.1073/pnas.1214062110