2JRY

Structure and Sodium Channel Activity of an Excitatory I1-Superfamily Conotoxin


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Structure and sodium channel activity of an excitatory I1-superfamily conotoxin.

Buczek, O.Wei, D.Babon, J.J.Yang, X.Fiedler, B.Chen, P.Yoshikami, D.Olivera, B.M.Bulaj, G.Norton, R.S.

(2007) Biochemistry 46: 9929-9940

  • DOI: 10.1021/bi700797f
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Conotoxin iota-RXIA, from the fish-hunting species Conus radiatus, is a member of the recently characterized I1-superfamily, which contains eight cysteine residues arranged in a -C-C-CC-CC-C-C- pattern. iota-RXIA (formerly designated r11a) is one of ...

    Conotoxin iota-RXIA, from the fish-hunting species Conus radiatus, is a member of the recently characterized I1-superfamily, which contains eight cysteine residues arranged in a -C-C-CC-CC-C-C- pattern. iota-RXIA (formerly designated r11a) is one of three characterized I1 peptides in which the third last residue is posttranslationally isomerized to the d configuration. Naturally occurring iota-RXIA with d-Phe44 is significantly more active as an excitotoxin than the l-Phe analogue both in vitro and in vivo. We have determined the solution structures of both forms by NMR spectroscopy, the first for an I1-superfamily member. The disulfide connectivities were determined from structure calculations and confirmed chemically as 5-19, 12-22, 18-27, and 21-38, suggesting that iota-RXIA has an ICK structural motif with one additional disulfide (21-38). Indeed, apart from the first few residues, the structure is well defined up to around residue 35 and does adopt an ICK structure. The C-terminal region, including Phe44, is disordered. Comparison of the d-Phe44 and l-Phe44 forms indicates that the switch from one enantiomer to the other has very little effect on the structure, even though it is clearly important for receptor interaction based on activity data. Finally, we identify the target of iota-RXIA as a voltage-gated sodium channel; iota-RXIA is an agonist, shifting the voltage dependence of activation of mouse NaV1.6 expressed in Xenopus oocytes to more hyperpolarized potentials. Thus, there is a convergence of structure and function in iota-RXIA, as its disulfide pairing and structure resemble those of funnel web spider toxins that also target sodium channels.


    Organizational Affiliation

    Department of Biology, University of Utah, Salt Lake City, Utah 84112, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
I-superfamily conotoxin r11a
A
46Conus radiatusMutation(s): 0 
Find proteins for Q7Z094 (Conus radiatus)
Go to UniProtKB:  Q7Z094
Small Molecules
Modified Residues  2 Unique
IDChainsTypeFormula2D DiagramParent
HYP
Query on HYP
A
L-PEPTIDE LINKINGC5 H9 N O3PRO
DPN
Query on DPN
A
D-PEPTIDE LINKINGC9 H11 N O2

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Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 
  • Olderado: 2JRY Olderado

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2007-10-23
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance