| Structural highlights
Function
KAX62_SCOPA Blocks voltage-gated potassium channels Kv1.2/KCNA2 (IC(50)=0.12-0.8 nM), KCa3.1/KCNN4 (IC(50)=1-2.2 nM), Shaker B (IC(50)=2.39-80 nM), Kv1.1/KCNA1 (IC(50)=37-45 or no activity, depending on the study), Kv1.3/KCNA3 (IC(50)=150-180 or no activity, depending on the study).[1] [2] [3] [4] [5] [6] [7]
Publication Abstract from PubMed
Maurotoxin (MTX) and HsTx1 are two scorpion toxins belonging to the alpha-KTx6 structural family. These 34-residue toxins, cross-linked by four disulfide bridges, share 59% sequence identity and fold along the classical alpha/beta scaffold. Despite these structural similarities, they fully differ in their pharmacological profiles. MTX is highly active on small (SK) and intermediate (IK) conductance Ca(2+)-activated (K(+)) channels and on voltage-gated Kv1.2 channel, whereas HsTx1 potently blocks voltage-gated Kv1.1 and Kv1.3 channels only. Here, we designed and chemically produced MTX-HsTx1, a chimera of both toxins that contains the N-terminal helical region of MTX (sequence 1-16) and the C-terminal beta-sheet region of HsTx1 (sequence 17-34). The three-dimensional structure of the peptide in solution was solved by (1)H NMR. MTX-HsTx1 displays the activity of MTX on SK channel, whereas it exhibits the pharmacological profile of HsTx1 on Kv1.1, Kv1.2, Kv1.3, and IK channels. These data demonstrate that the helical region of MTX exerts a key role in SK channel recognition, whereas the beta-sheet region of HsTx1 is crucial for activity on all other channel types tested.
Evidence for domain-specific recognition of SK and Kv channels by MTX and HsTx1 scorpion toxins.,Regaya I, Beeton C, Ferrat G, Andreotti N, Darbon H, De Waard M, Sabatier JM J Biol Chem. 2004 Dec 31;279(53):55690-6. Epub 2004 Oct 21. PMID:15498765[8]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Carlier E, Avdonin V, Geib S, Fajloun Z, Kharrat R, Rochat H, Sabatier JM, Hoshi T, De Waard M. Effect of maurotoxin, a four disulfide-bridged toxin from the chactoid scorpion Scorpio maurus, on Shaker K+ channels. J Pept Res. 2000 Jun;55(6):419-27. PMID:10888198
- ↑ Avdonin V, Nolan B, Sabatier JM, De Waard M, Hoshi T. Mechanisms of maurotoxin action on Shaker potassium channels. Biophys J. 2000 Aug;79(2):776-87. PMID:10920011 doi:http://dx.doi.org/10.1016/S0006-3495(00)76335-1
- ↑ Castle NA, London DO, Creech C, Fajloun Z, Stocker JW, Sabatier JM. Maurotoxin: a potent inhibitor of intermediate conductance Ca2+-activated potassium channels. Mol Pharmacol. 2003 Feb;63(2):409-18. PMID:12527813
- ↑ Regaya I, Beeton C, Ferrat G, Andreotti N, Darbon H, De Waard M, Sabatier JM. Evidence for domain-specific recognition of SK and Kv channels by MTX and HsTx1 scorpion toxins. J Biol Chem. 2004 Dec 31;279(53):55690-6. Epub 2004 Oct 21. PMID:15498765 doi:M410055200
- ↑ Pimentel C, M'Barek S, Visan V, Grissmer S, Sampieri F, Sabatier JM, Darbon H, Fajloun Z. Chemical synthesis and 1H-NMR 3D structure determination of AgTx2-MTX chimera, a new potential blocker for Kv1.2 channel, derived from MTX and AgTx2 scorpion toxins. Protein Sci. 2008 Jan;17(1):107-18. Epub 2007 Nov 27. PMID:18042681 doi:ps.073122908
- ↑ Kharrat R, Mabrouk K, Crest M, Darbon H, Oughideni R, Martin-Eauclaire MF, Jacquet G, el Ayeb M, Van Rietschoten J, Rochat H, Sabatier JM. Chemical synthesis and characterization of maurotoxin, a short scorpion toxin with four disulfide bridges that acts on K+ channels. Eur J Biochem. 1996 Dec 15;242(3):491-8. PMID:9022673
- ↑ Kharrat R, Mansuelle P, Sampieri F, Crest M, Oughideni R, Van Rietschoten J, Martin-Eauclaire MF, Rochat H, El Ayeb M. Maurotoxin, a four disulfide bridge toxin from Scorpio maurus venom: purification, structure and action on potassium channels. FEBS Lett. 1997 Apr 14;406(3):284-90. PMID:9136903
- ↑ Regaya I, Beeton C, Ferrat G, Andreotti N, Darbon H, De Waard M, Sabatier JM. Evidence for domain-specific recognition of SK and Kv channels by MTX and HsTx1 scorpion toxins. J Biol Chem. 2004 Dec 31;279(53):55690-6. Epub 2004 Oct 21. PMID:15498765 doi:M410055200
|
