2ph9

Galanthamine bound to an ACh-binding ProteinGalanthamine bound to an ACh-binding Protein

Structural highlights 2ph9 is a 5 chain structure with sequence from Aplysia californica. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.88Å Ligands: , Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q8WSF8_APLCA Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed 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. 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 SB, Taylor P J Mol Biol. 2007 Jun 15;369(4):895-901. Epub 2007 Mar 31. PMID:17481657 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Acetylcholine binding protein 3D structures

spinqualitylabelsall models 2ph9, resolution 2.88Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image