2LMZ

Solution NMR structure of the novel conotoxin im23a from Conus imperialis


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 200 
  • 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

A helical conotoxin from Conus imperialis has a novel cysteine framework and defines a new superfamily.

Ye, M.Khoo, K.K.Xu, S.Zhou, M.Boonyalai, N.Perugini, M.A.Shao, X.Chi, C.Galea, C.A.Wang, C.Norton, R.S.

(2012) J.Biol.Chem. 287: 14973-14983

  • DOI: 10.1074/jbc.M111.334615

  • PubMed Abstract: 
  • Cone snail venoms are a rich source of peptides, many of which are potent and selective modulators of ion channels and receptors. Here we report the isolation and characterization of two novel conotoxins from the venom of Conus imperialis. These two ...

    Cone snail venoms are a rich source of peptides, many of which are potent and selective modulators of ion channels and receptors. Here we report the isolation and characterization of two novel conotoxins from the venom of Conus imperialis. These two toxins contain a novel cysteine framework, C-C-C-CC-C, which has not been found in other conotoxins described to date. We name it framework XXIII and designate the two toxins im23a and im23b; cDNAs of these toxins exhibit a novel signal peptide sequence, which defines a new K-superfamily. The disulfide connectivity of im23a has been mapped by chemical mapping of partially reduced intermediates and by NMR structure calculations, both of which establish a I-II, III-IV, V-VI pattern of disulfide bridges. This pattern was also confirmed by synthesis of im23a with orthogonal protection of individual cysteine residues. The solution structure of im23a reveals that im23a adopts a novel helical hairpin fold. A cluster of acidic residues on the surface of the molecule is able to bind calcium. The biological activity of the native and recombinant peptides was tested by injection into mice intracranially and intravenously to assess the effects on the central and peripheral nervous systems, respectively. Intracranial injection of im23a or im23b into mice induced excitatory symptoms; however, the biological target of these new toxins has yet to be identified.


    Organizational Affiliation

    Institute of Protein Research, Tongji University, 1239 Siping Road, Shanghai 20092, China.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Conotoxin im17a
A
42Conus imperialisMutation(s): 0 
Find proteins for D0PX84 (Conus imperialis)
Go to UniProtKB:  D0PX84
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 200 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 
  • Olderado: 2LMZ Olderado

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2012-03-14
    Type: Initial release
  • Version 1.1: 2020-01-01
    Type: Data collection, Database references, Derived calculations