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PDBsum entry 2b3c
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Contents |
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* Residue conservation analysis
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References listed in PDB file
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Key reference
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Title
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Solution structure of a beta-Neurotoxin from the new world scorpion centruroides sculpturatus ewing.
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Authors
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M.J.Jablonsky,
P.L.Jackson,
J.O.Trent,
D.D.Watt,
N.R.Krishna.
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Ref.
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Biochem Biophys Res Commun, 1999,
254,
406-412.
[DOI no: ]
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PubMed id
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Abstract
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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.
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