2LO9

NMR solution structure of Mu-contoxin BuIIIB


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 1.2 of the entry. See complete history

Literature

Mammalian neuronal sodium channel blocker mu-conotoxin BuIIIB has a structured N-terminus that influences potency.

Kuang, Z.Zhang, M.M.Gupta, K.Gajewiak, J.Gulyas, J.Balaram, P.Rivier, J.E.Olivera, B.M.Yoshikami, D.Bulaj, G.Norton, R.S.

(2013) Acs Chem.Biol. 8: 1344-1351

  • DOI: 10.1021/cb300674x
  • Primary Citation of Related Structures:  2LOC

  • PubMed Abstract: 
  • Among the μ-conotoxins that block vertebrate voltage-gated sodium channels (VGSCs), some have been shown to be potent analgesics following systemic administration in mice. We have determined the solution structure of a new representative of this fami ...

    Among the μ-conotoxins that block vertebrate voltage-gated sodium channels (VGSCs), some have been shown to be potent analgesics following systemic administration in mice. We have determined the solution structure of a new representative of this family, μ-BuIIIB, and established its disulfide connectivities by direct mass spectrometric collision induced dissociation fragmentation of the peptide with disulfides intact. The major oxidative folding product adopts a 1-4/2-5/3-6 pattern with the following disulfide bridges: Cys5-Cys17, Cys6-Cys23, and Cys13-Cys24. The solution structure reveals that the unique N-terminal extension in μ-BuIIIB, which is also present in μ-BuIIIA and μ-BuIIIC but absent in other μ-conotoxins, forms part of a short α-helix encompassing Glu3 to Asn8. This helix is packed against the rest of the toxin and stabilized by the Cys5-Cys17 and Cys6-Cys23 disulfide bonds. As such, the side chain of Val1 is located close to the aromatic rings of Trp16 and His20, which are located on the canonical helix that displays several residues found to be essential for VGSC blockade in related μ-conotoxins. Mutations of residues 2 and 3 in the N-terminal extension enhanced the potency of μ-BuIIIB for NaV1.3. One analogue, [d-Ala2]BuIIIB, showed a 40-fold increase, making it the most potent peptide blocker of this channel characterized to date and thus a useful new tool with which to characterize this channel. On the basis of previous results for related μ-conotoxins, the dramatic effects of mutations at the N-terminus were unanticipated and suggest that further gains in potency might be achieved by additional modifications of this region.


    Organizational Affiliation

    The Walter and Eliza Hall Institute of Medical Research , 1G Royal Parade, Parkville, Victoria, 3052, Australia.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Mu-conotoxin BuIIIB
A
25Conus bullatusN/A
Find proteins for C1J5M6 (Conus bullatus)
Go to UniProtKB:  C1J5M6
Small Molecules
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
NH2
Query on NH2
A
NON-POLYMERH2 N

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Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 200 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 
  • Olderado: 2LO9 Olderado

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

  • Deposited Date: 2012-01-20 
  • Released Date: 2013-01-23 
  • Deposition Author(s): Kuang, Z.

Revision History 

  • Version 1.0: 2013-01-23
    Type: Initial release
  • Version 1.1: 2013-09-11
    Type: Database references
  • Version 1.2: 2014-02-19
    Type: Database references