2PH9

Galanthamine bound to an ACh-binding Protein


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.88 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.205 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Galanthamine and non-competitive inhibitor binding to ACh-binding protein: evidence for a binding site on non-alpha-subunit interfaces of heteromeric neuronal nicotinic receptors.

Hansen, S.B.Taylor, P.

(2007) J.Mol.Biol. 369: 895-901

  • DOI: 10.1016/j.jmb.2007.03.067
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Rapid neurotransmission is mediated through a superfamily of Cys-loop receptors that includes the nicotinic acetylcholine (nAChR), gamma-aminobutyric acid (GABA(A)), serotonin (5-HT(3)) and glycine receptors. A class of ligands, including galanthamin ...

    Rapid neurotransmission is mediated through a superfamily of Cys-loop receptors that includes the nicotinic acetylcholine (nAChR), gamma-aminobutyric acid (GABA(A)), serotonin (5-HT(3)) and glycine receptors. A class of ligands, including galanthamine, local anesthetics and certain toxins, interact with nAChRs non-competitively. Suggested modes of action include blockade of the ion channel, modulation from undefined extracellular sites, stabilization of desensitized states, and association with annular or boundary lipid. Alignment of mammalian Cys-loop receptors shows aromatic residues, found in the acetylcholine or ligand-binding pocket of nAChRs, are conserved in all subunit interfaces of neuronal nAChRs, including those that are not formed by alpha subunits on the principal side of the transmitter binding site. The amino-terminal domain containing the ligand recognition site is homologous to the soluble acetylcholine-binding protein (AChBP) from mollusks, an established structural and functional surrogate. We assess ligand specificity and employ X-ray crystallography with AChBP to demonstrate ligand interactions at subunit interfaces lacking vicinal cysteines (i.e. the non-alpha subunit interfaces in nAChRs). Non-competitive nicotinic ligands bind AChBP with high affinity (K(d) 0.015-6 microM). We mutated the vicinal cysteine residues in loop C of AChBP to mimic the non-alpha subunit interfaces of neuronal nAChRs and other Cys loop receptors. Classical nicotinic agonists show a 10-40-fold reduction in binding affinity, whereas binding of ligands known to be non-competitive are not affected. X-ray structures of cocaine and galanthamine bound to AChBP (1.8 A and 2.9 A resolution, respectively) reveal interactions deep within the subunit interface and the absence of a contact surface with the tip of loop C. Hence, in addition to channel blocking, non-competitive interactions with heteromeric neuronal nAChR appear to occur at the non-alpha subunit interface, a site presumed to be similar to that of modulating benzodiazepines on GABA(A) receptors.


    Organizational Affiliation

    Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093-0650, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Soluble acetylcholine receptor
A, B, C, D, E
230Aplysia californicaMutation(s): 0 
Find proteins for Q8WSF8 (Aplysia californica)
Go to UniProtKB:  Q8WSF8
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
PG4
Query on PG4

Download SDF File 
Download CCD File 
B
TETRAETHYLENE GLYCOL
C8 H18 O5
UWHCKJMYHZGTIT-UHFFFAOYSA-N
 Ligand Interaction
GNT
Query on GNT

Download SDF File 
Download CCD File 
A, C, D, E
(-)-GALANTHAMINE
C17 H21 N O3
ASUTZQLVASHGKV-JDFRZJQESA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
GNTKd: 1300 nM PDBBIND
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.88 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.205 
  • Space Group: C 2 2 21
Unit Cell:
Length (Å)Angle (°)
a = 143.950α = 90.00
b = 145.472β = 90.00
c = 143.555γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
HKL-2000data scaling
DENZOdata reduction
AMoREphasing
SCALEPACKdata scaling
PDB_EXTRACTdata extraction
HKL-2000data collection
HKL-2000data reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2007-07-03
    Type: Initial release
  • Version 1.1: 2008-05-01
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Advisory, Refinement description, Version format compliance
  • Version 1.3: 2017-10-18
    Type: Refinement description