Solution structure of toxin 2 from Centruroides noxius Hoffmann, a β-scorpion neurotoxin acting on sodium channels 1 1Edited by P. E. Wright

Pintar, Alessandro; Possani, Lourival D.; Delepierre, Muriel

doi:10.1006/jmbi.1999.2611

Cited by 76 publications

(60 citation statements)

References 45 publications

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“…This region has been shown to be important for neutralizing the toxic effect of Cn2 in mice by means of BCF2, a neutralizing mouse antibody that recognizes Cn2 (14,40) and synthetic peptides corresponding to these segments of the primary Cn2 structure (39). Furthermore, NMR three-dimensional structure determinations have shown that the same Cn2 segments are spatially packed together (13,41). The segment that mainly comprises the loop in positions Asp 7 -Cys 11 forms the central part of the epitope, a region that differs significantly between the primary structures of Cn2 and CssIV, as discussed above From top to bottom the following accession numbers have been used: P04775, P35498, Q99250, Q9NY46, P35499, Q14524, Q9UQD0, Q9WTU3, and O08562.…”

Section: Discussionmentioning

confidence: 99%

“…Additionally, the first 17 amino acid residues in the N-terminal region of CssIV were directly determined on the basis of automatic Edman degradation (LF 3000 Protein Sequencer; Beckman) in order to confirm the sequence. The CssIV sequence underwent homology modeling using the SWISS-MODEL server (17) and the lowest energy conformer in the Protein Data Bank entry 1Cn2 as template (13). After a second round of refinement, the quality of the final model is equivalent to that of the template (assessed by the WHAT_CHECK program (18)), so no further (on-bench) refinement was used.…”

Section: Toxin Purification and Molecular Modelingmentioning

confidence: 99%

“…We studied the biophysical effects of Cn2 toxin (13) purified from the venom of the Mexican scorpion Centruroides noxius on various human Na ϩ channel isoforms (Na v 1.1-Na v 1.7). We discovered that Cn2 is only capable of inducing the voltage sensor-trapping mechanism in the hNa v 1.6 channel current recorded in stably transfected HEK cells and in wild-type cerebellar Purkinje cells.…”

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confidence: 99%

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Resurgent Current and Voltage Sensor Trapping Enhanced Activation by a β-Scorpion Toxin Solely in Nav1.6 Channel

Schiavon

Sacco

Cassulini

et al. 2006

Journal of Biological Chemistry

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109

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Resurgent currents are functionally crucial in sustaining the high frequency firing of cerebellar Purkinje neurons expressing Na v 1.6 channels. ␤-Scorpion toxins, such as CssIV, induce a left shift in the voltage-dependent activation of Na v 1.2 channels by "trapping" the IIS4 voltage sensor segment. We found that the dangerous Cn2 ␤-scorpion peptide induces both the left shift voltage-dependent activation and a transient resurgent current only in human Na v 1.6 channels (among 1.1-1.7), whereas CssIV did not induce the resurgent current. Cn2 also produced both actions in mouse Purkinje cells. These findings suggest that only distinct ␤-toxins produce resurgent currents. We suggest that the novel and unique selectivity of Cn2 could make it a model drug to replace deep brain stimulation of the subthalamic nucleus in patients with Parkinson disease.

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Section: Discussionmentioning

confidence: 99%

Section: Toxin Purification and Molecular Modelingmentioning

confidence: 99%

mentioning

confidence: 99%

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Resurgent Current and Voltage Sensor Trapping Enhanced Activation by a β-Scorpion Toxin Solely in Nav1.6 Channel

Schiavon

Sacco

Cassulini

et al. 2006

Journal of Biological Chemistry

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109

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“…1) (15). Forty residues, which, according to the structural model, are exposed to the solvent, were scanned by substitution (mostly to Ala).…”

Section: Expression and Characterization Of Recombinantmentioning

confidence: 99%

“…However, Bj-xtrIT differs prominently from anti-mammalian ␤-toxins (e.g. Cn2 from Centruroides noxius, Css2, and Css4) in specificity (5,9,(12)(13)(14) and structure (8,15,16). It shares only 27% sequence identity with Css4, and the spatial arrangement of the fourth disulfide bridge and C-tail configuration vary greatly ( Fig.…”

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confidence: 99%

Common Features in the Functional Surface of Scorpion β-Toxins and Elements That Confer Specificity for Insect and Mammalian Voltage-gated Sodium Channels

Cohen

Karbat

Gilles

et al. 2005

Journal of Biological Chemistry

125

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Scorpion ␤-toxins that affect the activation of mammalian voltage-gated sodium channels (Na v s) have been studied extensively, but little is known about their functional surface and mode of interaction with the channel receptor. To enable a molecular approach to this question, we have established a successful expression system for the anti-mammalian scorpion ␤-toxin, Css4, whose effects on rat brain Na v s have been well characterized. A recombinant toxin, His-Css4, was obtained when fused to a His tag and a thrombin cleavage site and had similar binding affinity for and effect on Na currents of rat brain sodium channels as those of the native toxin isolated from the scorpion venom. Molecular dissection of His-Css4 elucidated a functional surface of 1245 Å 2 composed of the following: 1) a cluster of residues associated with the ␣-helix, which includes a putative "hot spot" (this cluster is conserved among scorpion ␤-toxins and contains their "pharmacophore"); 2) a hydrophobic cluster associated mainly with the ␤2 and ␤3 strands, which is likely to confer the specificity for mammalian Na v s; 3) a single bioactive residue (Trp-58) in the C-tail; and 4) a negatively charged residue (Glu-15) involved in voltage sensor trapping as inferred from our ability to uncouple toxin binding from activity upon its substitution. This study expands our understanding about the mode of action of scorpion ␤-toxins and illuminates differences in the functional surfaces that may dictate their specificities for mammalian versus insect sodium channels.

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Antibody BCF2 against scorpion toxin cn2 fromCentruroides noxius hoffmann: Primary structure and three-dimensional model as free fv fragment and complexed with its antigen

et al. 1999

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The antibody BCF2 generated against the mammal-specific toxin Cn2 of the scorpion Centuroides noxius Hoffmann neutralizes the effect of both the toxin and the venom. We cloned and sequenced the genes coding for the Fv fragment of BCF2. A three-dimensional (3D) model of the Fv fragment was generated using a knowledge-based approach. Furthermore, a 3D model of the complex Cn2-BCF2 was built using the nuclear magnetic resonance (NMR) structure of Cn2 and experimental results on a putative epitope region around the N and C termini. The initial complex conformations were submitted to a new refinement procedure of rigid-body energy minimization combined with flexible-side-chain molecular dynamics. The final complex, selected after an extensive evaluation, uses the loop 7-11 as the central part of the epitope. The generated complex allows the following conclusions: 1) the neutralizing capacity of BCF2 toward the venom of C. noxius might rather be caused by the high venom concentration and toxicity of Cn2 than by a broad specificity, 2) the region involved in the binding of Cn2 to the Na(+) channel, should overlap with the employed epitope region, and 3) contact residues SerL91, AsnL92, LeuH50, AspH56, TyrH95, and TyrH98 of BCF2 are candidates for mutations to broaden its specificity. Proteins 1999;37:130-143.

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Solution structure of toxin 2 from Centruroides noxius Hoffmann, a β-scorpion neurotoxin acting on sodium channels 1 1Edited by P. E. Wright

Cited by 76 publications

References 45 publications

Resurgent Current and Voltage Sensor Trapping Enhanced Activation by a β-Scorpion Toxin Solely in Nav1.6 Channel

Resurgent Current and Voltage Sensor Trapping Enhanced Activation by a β-Scorpion Toxin Solely in Nav1.6 Channel

Common Features in the Functional Surface of Scorpion β-Toxins and Elements That Confer Specificity for Insect and Mammalian Voltage-gated Sodium Channels

Antibody BCF2 against scorpion toxin cn2 fromCentruroides noxius hoffmann: Primary structure and three-dimensional model as free fv fragment and complexed with its antigen

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