PDBsum entry 2b3c

Toxin

PDB id: 2b3c

Contents

Protein chain

64 a.a. *

* Residue conservation analysis

PDB id:

2b3c

Name:

Toxin

Title:

Solution structure of a beta-neurotoxin from the new world scorpion centruroides sculpturatus ewing

Structure:

Protein (neurotoxin cse-i). Chain: a

Source:

Centruroides sculpturatus. Bark scorpion. Organism_taxid: 218467. Other_details: scorpions collected mesa, az, usa

NMR struc:

1 models

Authors:

M.J.Jablonsky,P.L.Jackson,J.O.Trent,D.D.Watt,N.R.Krishna

Key ref:

M.J.Jablonsky et al. (1999). Solution structure of a beta-neurotoxin from the New World scorpion Centruroides sculpturatus Ewing. Biochem Biophys Res Commun, 254, 406-412. PubMed id: 9918851 DOI: 10.1006/bbrc.1998.9904

Date:

09-Dec-98 Release date: 16-Dec-98

Protein chain

P01491  (SCXI_CENSC) -  Beta-toxin CsEI from Centruroides sculpturatus

Seq: 86 a.a.

Struc: 64 a.a.

DOI no: 10.1006/bbrc.1998.9904

Biochem Biophys Res Commun 254:406-412 (1999)

PubMed id: 9918851

Solution structure of a beta-neurotoxin from the New World scorpion Centruroides sculpturatus Ewing.

M.J.Jablonsky, P.L.Jackson, J.O.Trent, D.D.Watt, N.R.Krishna.

ABSTRACT

We report the detailed solution structure of the 7.2 kDa protein CsE-I, a beta-neurotoxin from the New World scorpion Centruroides sculpturatus Ewing. This toxin binds to sodium channels, but unlike the alpha-neurotoxins, shifts the voltage of activation toward more negative potentials causing the membrane to fire spontaneously. Sequence-specific proton NMR assignments were made using 600 MHz 2D-NMR data. Distance geometry and dynamical simulated annealing refinements were performed using experimental distance and torsion angle constraints from NOESY and pH-COSY data. A family of 40 structures without constraint violations was generated, and an energy-minimized average structure was computed. The backbone conformation of the CsE-I toxin shows similar secondary structural features as the prototypical alpha-neurotoxin, CsE-v3, and is characterized by a short 2(1/2)-turn alpha-helix and a 3-strand antiparallel beta-sheet, both held together by disulfide bridges. The RMSD for the backbone atoms between CsE-I and CsE-v3 is 1.48 A. Despite this similarity in the overall backbone folding, the these two proteins show some important differences in the primary structure (sequence) and electrostatic potential surfaces. Our studies provide a basis for unravelling the role of these differences in relation to the known differences in the receptor sites on the voltage sensitive sodium channel for the alpha- and beta-neurotoxins.