1IXT

Structure of a Novel P-Superfamily Spasmodic Conotoxin Reveals an Inhibitory Cystine Knot Motif


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 200 
  • Conformers Submitted: 20 
  • Selection Criteria: back calculated data agree with experimental NOESY spectrum,structures with the least restraint violations,structures with the lowest energy 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structure of a Novel P-Superfamily Spasmodic Conotoxin Reveals an Inhibitory Cystine Knot Motif

Miles, L.A.Dy, C.Y.Nielsen, J.Barnham, K.J.Hinds, M.G.Olivera, B.M.Bulaj, G.Norton, R.S.

(2002) J.Biol.Chem. 277: 43033-43040

  • DOI: 10.1074/jbc.M206690200

  • PubMed Abstract: 
  • Conotoxin gm9a, a putative 27-residue polypeptide encoded by Conus gloriamaris, was recently identified as a homologue of the "spasmodic peptide", tx9a, isolated from the venom of the mollusk-hunting cone shell Conus textile (Lirazan, M. B., Hooper, ...

    Conotoxin gm9a, a putative 27-residue polypeptide encoded by Conus gloriamaris, was recently identified as a homologue of the "spasmodic peptide", tx9a, isolated from the venom of the mollusk-hunting cone shell Conus textile (Lirazan, M. B., Hooper, D., Corpuz, G. P., Ramilo, C. A., Bandyopadhyay, P., Cruz, L. J., and Olivera, B. M. (2000) Biochemistry 39, 1583-1588). The C. gloriamaris spasmodic peptide has been synthesized, and the refolded polypeptide was shown to be biologically active using a mouse bioassay. The chemically synthesized gm9a elicited the same symptomatology described previously for natively folded tx9a, and gm9a and tx9a were of similar potency, implying that neither the two gamma-carboxyglutamate (Gla) residues found in tx9a (Ser(8) and Ala(13) in gm9a) nor Gly(1) (Ser(1) in gm9a) are crucial for biological activity. We have determined the three-dimensional structure of gm9a in aqueous solution and demonstrated that the molecule adopts the well known inhibitory cystine knot motif constrained by three disulfide bonds involving Cys(2)-Cys(16), Cys(6)-Cys(18) and Cys(12)-Cys(23). Based on the gm9a structure, the sites of Gla substitution in tx9a are in loops located on one surface of the molecule, which is unlikely to be involved directly in receptor binding. Because this is the first structure reported for a member of the newly defined P-superfamily conotoxins, a comparison has been made with structurally related conotoxins. This shows that the structural scaffold that characterizes the P-conotoxins has the greatest potential for exhibiting structural diversity among the robust inhibitory cystine knot-containing conotoxins, a finding that has implications for functional epitope mimicry and protein engineering.


    Organizational Affiliation

    The Walter and Eliza Hall Institute of Medical Research, NMR Laboratory, 381 Royal Parade, Parkville 3052, Australia.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
spasmodic protein tx9a-like protein
A
27Conus gloriamarisN/A
Find proteins for Q9GU57 (Conus gloriamaris)
Go to UniProtKB:  Q9GU57
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 200 
  • Conformers Submitted: 20 
  • Selection Criteria: back calculated data agree with experimental NOESY spectrum,structures with the least restraint violations,structures with the lowest energy 
  • Olderado: 1IXT Olderado

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2003-01-28
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance