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 
  • R-Value Observed: 0.171 

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 U S A 103: 3615

  • DOI: 10.1073/pnas.0507889103
  • Primary Citation of Related Structures:  
    2C9T

  • 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 the receptor is unknown at the structural level ...

    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:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
SOLUBLE ACETYLCHOLINE RECEPTOR
A, B, C, D, E, F, G, H
A, B, C, D, E, F, G, H, I, J
217Aplysia californicaMutation(s): 0 
UniProt
Find proteins for Q8WSF8 (Aplysia californica)
Explore Q8WSF8 
Go to UniProtKB:  Q8WSF8
Protein Feature View
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  • Reference Sequence
  • Find similar proteins by:  Sequence   |   Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
ALPHA-CONOTOXIN IMIK, L [auth M], M [auth O], N [auth P], O [auth Q], P [auth R], Q [auth S], R [auth T]13Conus imperialisMutation(s): 0 
UniProt
Find proteins for P50983 (Conus imperialis)
Explore P50983 
Go to UniProtKB:  P50983
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.25 Å
  • R-Value Free: 0.227 
  • R-Value Work: 0.168 
  • R-Value Observed: 0.171 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 113.211α = 90
b = 123.131β = 117.47
c = 118.749γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
MOSFLMdata reduction
SCALAdata scaling
MOLREPphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

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