8.B.8 The α-KTx15 Scorpion Toxin (α-KTx15) Family
Discrepin is a scorpion peptide that blocks preferentially the I(A) currents of the voltage-dependent K(+) channel of rat cerebellum granular cells. It was isolated from the venom of the buthid scorpion Tityus discrepans and contains 38 amino acid residues with a pyroglutamic acid at the N-terminal site. Discrepin has the lowest sequence identity (approx. 50%) among the six members of the α-KTx15 sub-family of scorpion toxins (Romeo et al., 2008).
This family belongs to the: Defensin Superfamily.
References associated with 8.B.8 family:
Abbas, N., M. Belghazi, Y. Abdel-Mottaleb, J. Tytgat, P.E. Bougis, and M.F. Martin-Eauclaire. (2008). A new Kaliotoxin selective towards Kv1.3 and Kv1.2 but not Kv1.1 channels expressed in oocytes. Biochem. Biophys. Res. Commun. 376: 525-530. 18804453
Huys, I., C.Q. Xu, C.Z. Wang, H. Vacher, M.F. Martin-Eauclaire, C.W. Chi, and J. Tytgat. (2004). BmTx3, a scorpion toxin with two putative functional faces separately active on A-type K+ and HERG currents. Biochem. J. 378: 745-752. 14599291
Luna-Ramírez, K., A. Bartok, R. Restano-Cassulini, V. Quintero-Hernández, F.I. Coronas, J. Christensen, C.E. Wright, G. Panyi, and L.D. Possani. (2014). Structure, molecular modeling, and function of the novel potassium channel blocker urotoxin isolated from the venom of the Australian scorpion Urodacus yaschenkoi. Mol Pharmacol 86: 28-41. 24723491
Place, A.R., J. Ramos-Franco, A.L. Waters, J. Peng, and M.T. Hamann. (2024). Sterolysin from a 1950s culture of Karlodinium veneficum (aka Gymnodinium veneficum Ballantine) forms lethal sterol dependent membrane pores. Sci Rep 14: 17998. 39097621
Prochnicka-Chalufour, A., G. Corzo, H. Satake, M.F. Martin-Eauclaire, A.R. Murgia, G. Prestipino, G. D'Suze, L.D. Possani, and M. Delepierre. (2006). Solution structure of discrepin, a new K+ -channel blocking peptide from the α- KTx15 subfamily. Biochemistry. 45: 1795-1804. 16460026
Romeo, S., G. Corzo, A. Vasile, H. Satake, G. Prestipino, and L.D. Possani. (2008). A positive charge at the N-terminal segment of Discrepin increases the blocking effect of K+ channels responsible for the I(A) currents in cerebellum granular cells. Biochim. Biophys. Acta. 1780: 750-755. 18280256