2C9T

Crystal Structure Of Acetylcholine Binding Protein (AChBP) From Aplysia Californica In Complex With alpha-Conotoxin ImI


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.25 Å
  • R-Value Free: 0.227 
  • R-Value Work: 0.168 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural Determinants of Selective {Alpha}-Conotoxin Binding to a Nicotinic Acetylcholine Receptor Homolog Achbp.

Ulens, C.Hogg, R.C.Celie, P.H.Bertrand, D.Tsetlin, V.Smit, A.B.Sixma, T.K.

(2006) Proc.Natl.Acad.Sci.USA 103: 3615

  • DOI: 10.1073/pnas.0507889103
  • Also Cited By: 2MOA

  • PubMed Abstract: 
  • The nicotinic acetylcholine receptor (nAChR) is the prototype member of the superfamily of pentameric ligand-gated ion channels. How the extracellular ligand-binding domain coordinates selective binding of ligand molecules to different subtypes of th ...

    The nicotinic acetylcholine receptor (nAChR) is the prototype member of the superfamily of pentameric ligand-gated ion channels. How the extracellular ligand-binding domain coordinates selective binding of ligand molecules to different subtypes of the receptor is unknown at the structural level. Here, we present the 2.2-A crystal structure of a homolog of the ligand-binding domain of the nAChR, Aplysia californica AChBP (Ac-AChBP), in complex with alpha-conotoxin ImI. This conotoxin is unique in its selectivity toward the neuronal alpha3beta2 and alpha7 nAChR, a feature that is reflected in its selective binding to Ac-AChBP compared with other AChBP homologs. We observe a network of interactions between the residues of the ligand-binding site and the toxin, in which ImI Arg-7 and Trp-10 play a key role. The toxin also forms interactions in the ligand-binding site that were not seen in the complex of Ac-AChBP with PnIA(A10L D14K), a conotoxin variant that lacks binding selectivity to AChBP homologs. In combination with electrophysiological recordings obtained by using the wild-type alpha7 nAChR and L247T mutant, we show that conotoxin ImI inhibits ion conduction by stabilizing the receptor in a desensitized conformation. Comparison of the Ac-AChBP-ImI crystal structure with existing AChBP structures offers structural insight into the extent of flexibility of the interface loops and how their movement may couple ligand binding to channel gating in the context of a nAChR.


    Organizational Affiliation

    Division of Molecular Carcinogenesis, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
SOLUBLE ACETYLCHOLINE RECEPTOR
A, B, C, D, E, F, G, H, I, J
217Aplysia californica
Find proteins for Q8WSF8 (Aplysia californica)
Go to UniProtKB:  Q8WSF8
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
ALPHA-CONOTOXIN IMI
K, M, O, P, Q, R, S, T
13Conus imperialis
Find proteins for P50983 (Conus imperialis)
Go to UniProtKB:  P50983
Small Molecules
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
NH2
Query on NH2
K, M, O, P, Q, R, S, T
NON-POLYMERH2 N

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Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.25 Å
  • R-Value Free: 0.227 
  • R-Value Work: 0.168 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 113.211α = 90.00
b = 123.131β = 117.47
c = 118.749γ = 90.00
Software Package:
Software NamePurpose
MOSFLMdata reduction
REFMACrefinement
SCALAdata scaling
MOLREPphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2006-02-13
    Type: Initial release
  • Version 1.1: 2011-05-08
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance