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Analysis of the interacting surface of maurotoxin with the voltage-gated Shaker B K(+) channel.: Mechanism of block of the Shaker B K+ channel by the scorpion toxin MTX
- Source :
- Journal of Peptide Science, Journal of Peptide Science, Wiley, 2011, 17 (3), pp.200-10. ⟨10.1002/psc.1313⟩
- Publication Year :
- 2011
- Publisher :
- HAL CCSD, 2011.
-
Abstract
- International audience; Maurotoxin (MTX) is a 34-residue toxin that was isolated initially from the venom of the scorpion Scorpio maurus palmatus. Unlike the other toxins of the α-KTx6 family (Pi1, Pi4, Pi7, and HsTx1), MTX exhibits a unique disulfide bridge organization of the type C(1) C(5) , C(2) C(6) , C(3) C(4) , and C(7) C(8) (instead of the conventional C(1) C(5) , C(2) C(6) , C(3) C(7) , and C(4) C(8) , herein referred to as Pi1-like) that does not prevent its folding along the classic α/β scaffold of scorpion toxins. MTX(Pi1) is an MTX variant with a conventional pattern of disulfide bridging without any primary structure alteration of the toxin. Here, using MTX and/or MTX(Pi1) as models, we investigated how the type of folding influences toxin recognition of the Shaker B potassium channel. Amino acid residues of MTX that were studied for Shaker B recognition were selected on the basis of their homologous position in charybdotoxin, a three disulfide-bridged scorpion toxin also active on this channel type. These residues favored either an MTX- or MTX(Pi1) -like folding. Our data indicate clearly that Lys(23) and Tyr(32) (two out of ten amino acid residues studied) are the most important residues for Shaker B channel blockage by MTX. For activity on SKCa channels, the same amino acid residues also affect, directly or indirectly, the recognition of SK channels. The molecular modeling technique and computed docking indicate the existence of a correlation between the half cystine pairings of the mutated analogs and their activity on the Shaker B K(+) channel. Overall, mutations in MTX could, or could not, change the reorganization of disulfide bridges of this molecule without affecting its α/β scaffold. However, changing of the peptide backbone (cross linking disulfide bridges from MTX-like type vs MTX(Pi1) -like type) appears to have less impact on the molecule activity than mutation of certain key amino acids such as Lys(23) and Tyr(32) in this toxin.
- Subjects :
- musculoskeletal diseases
shaker B K+ channel
MESH: Electrophysiology
MESH: Rats
computed docking
molecular modelling
protein-protein interaction
maurotoxin
MESH: Protein Conformation
MESH: Scorpion Venoms
MESH: Synaptosomes
MESH: Protein Binding
MESH: Animals
[SDV.NEU]Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC]
[SDV.NEU] Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC]
skin and connective tissue diseases
MESH: Potassium Channels, Voltage-Gated
MESH: Point Mutation
Subjects
Details
- Language :
- English
- ISSN :
- 10752617 and 10991387
- Database :
- OpenAIRE
- Journal :
- Journal of Peptide Science, Journal of Peptide Science, Wiley, 2011, 17 (3), pp.200-10. ⟨10.1002/psc.1313⟩
- Accession number :
- edsair.od......1398..b4e01d4c64ca70403609e4dfdebbda3a