Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Submitted: 

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This is version 1.3 of the entry. See complete history


Sequential assignment and structure determination of spider toxin omega-Aga-IVB.

Yu, H.Rosen, M.K.Saccomano, N.A.Phillips, D.Volkmann, R.A.Schreiber, S.L.

(1993) Biochemistry 32: 13123-13129

  • DOI: https://doi.org/10.1021/bi00211a022
  • Primary Citation of Related Structures:  
    1OMA, 1OMB

  • PubMed Abstract: 

    The solution structure of a peptide toxin isolated from funnel web spider venom, omega-Aga-IVB, was determined by 2D NMR methods. omega-Aga-IVB is a high-affinity specific blocker of P-type voltage-dependent calcium channels. Nearly all of the proton resonances of this 48-residue protein were assigned using conventional 2D homonuclear NMR experiments. The three-dimensional structure of the molecule was determined by simulated annealing. The distance and dihedral restraints used in the structure calculations were derived from NOESY and COSY-type experiments, respectively. Mass spectrometric analysis of omega-Aga-IVB suggests that the protein contains four disulfide bonds. In the absence of chemical data to identify the pattern of cysteine pairing, the disulfide bonds of the toxin are proposed from the NMR data and subsequent structural calculations. The structure of the toxin can be described as a three-stranded anti-parallel beta sheet connected by flexible loops. A striking feature of the structure is that the C-terminal 10 residues of this protein adopt random coil conformations. Several positively charged amino acid side chains are found localized on one face of the molecule, in close proximity to the C-terminal tail. This observation has led us to propose a speculative model of the toxins blockade mechanism.

  • Organizational Affiliation

    Department of Chemistry, Harvard University, Cambridge, Massachusetts 02138.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
OMEGA-AGA-IVB48Agelenopsis apertaMutation(s): 0 
Find proteins for P37045 (Agelenopsis aperta)
Explore P37045 
Go to UniProtKB:  P37045
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UniProt GroupP37045
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Submitted: 

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1993-10-31
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-11-29
    Changes: Derived calculations, Other