PDBsum entry 1v7f

Toxin

PDB id: 1v7f

Contents

Protein chain

30 a.a.

PDB id:

1v7f

Name:

Toxin

Title:

Solution structure of phrixotoxin 1

Structure:

Phrixotoxin 1. Chain: a. Synonym: patx1. Engineered: yes

Source:

Synthetic: yes. Paraphysa scrofa. Organism_taxid: 269635. Other_details: chemically synthetized

NMR struc:

25 models

Authors:

B.Chagot,P.Escoubas,E.Villegas,C.Bernard,G.Ferrat,G.Corzo, M.Lazdunski,H.Darbon

Key ref:

B.Chagot et al. (2004). Solution structure of Phrixotoxin 1, a specific peptide inhibitor of Kv4 potassium channels from the venom of the theraphosid spider Phrixotrichus auratus. Protein Sci, 13, 1197-1208. PubMed id: 15096626 DOI: 10.1110/ps.03584304

Date:

16-Dec-03 Release date: 23-Nov-04

Protein chain

P61230  (TXP1_PARSR) -  Kappa-theraphotoxin-Ps1a from Paraphysa scrofa

Seq: 29 a.a.

Struc: 30 a.a.

DOI no: 10.1110/ps.03584304

Protein Sci 13:1197-1208 (2004)

PubMed id: 15096626

Solution structure of Phrixotoxin 1, a specific peptide inhibitor of Kv4 potassium channels from the venom of the theraphosid spider Phrixotrichus auratus.

B.Chagot, P.Escoubas, E.Villegas, C.Bernard, G.Ferrat, G.Corzo, M.Lazdunski, H.Darbon.

ABSTRACT

Animal toxins block voltage-dependent potassium channels (Kv) either by occluding the conduction pore (pore blockers) or by modifying the channel gating properties (gating modifiers). Gating modifiers of Kv channels bind to four equivalent extracellular sites near the S3 and S4 segments, close to the voltage sensor. Phrixotoxins are gating modifiers that bind preferentially to the closed state of the channel and fold into the Inhibitory Cystine Knot structural motif. We have solved the solution structure of Phrixotoxin 1, a gating modifier of Kv4 potassium channels. Analysis of the molecular surface and the electrostatic anisotropy of Phrixotoxin 1 and of other toxins acting on voltage-dependent potassium channels allowed us to propose a toxin interacting surface that encompasses both the surface from which the dipole moment emerges and a neighboring hydrophobic surface rich in aromatic residues.

Selected figure(s)

Figure 4.
Figure 4. (A) MOLSCRIPT representation of the structure of ICK toxins that act against K[V] channels. From left to right: PaTx1 and HpTx2 (Kv4.2), HaTx1 (Kv2.1), -PVIIA (shaker K+). (B) Sequence alignment of PaTx1 with other toxins acting against K+ channels. PaTx1, PaTx2 (Phrixotoxins 1 and 2) from Phrixotrichus auratus, HpTx2 (Heteropodatoxin 2) from Heteropoda venatoria, HaTx1 (Hanatoxin 1) from Grammostola spatulata, ScTx1 (Stromatoxin 1) from Stromatopelma calceata, HmTx1 (Heteroscodratoxin 1) from Heteroscodra maculata, PVIIA ( -conotoxin PVIIA) from Conus purpurascens (see references in text).

Figure 5.
Figure 5. (A) Orientation of the dipole moment of PaTx1 (top center) emerging through Lys 26. The resulting putative functional surface of PaTx1 is represented (in the same orientation) in B, centered around Lys 26 and the hydrophobic patch (top center). The same procedure was used to generate the corresponding dipoles of HaTx1 (top left), HpTx2 (top right), ScTx1 (bottom left), and PaTx2 (bottom right). The residues are colored green for polar uncharged residues, blue for basic residues, red for acidic residues, purple for aromatic residues, and yellow for aromatic residues. (B) Putative functional surfaces of the toxins represented in CPK (TURBO software), in the same orientation as in A, centered around basic residues and the hydrophobic patch. The residues are colored green for polar uncharged residues, blue for basic residues, red for acidic residues, purple for aromatic residues, and yellow for aliphatic residues.

The above figures are reprinted by permission from the Protein Society: Protein Sci (2004, 13, 1197-1208) copyright 2004.

Figures were selected by an automated process.