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==1.1 ANGSTROM CRYSTAL STRUCTURE OF A-CONOTOXIN [TYR15]-EPI== | |||
<StructureSection load='1a0m' size='340' side='right'caption='[[1a0m]], [[Resolution|resolution]] 1.10Å' scene=''> | |||
| | == Structural highlights == | ||
<table><tr><td colspan='2'>[[1a0m]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Conus_episcopatus Conus episcopatus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1A0M OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1A0M FirstGlance]. <br> | |||
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.1Å</td></tr> | |||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=NH2:AMINO+GROUP'>NH2</scene></td></tr> | |||
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1a0m FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1a0m OCA], [https://pdbe.org/1a0m PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1a0m RCSB], [https://www.ebi.ac.uk/pdbsum/1a0m PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1a0m ProSAT]</span></td></tr> | |||
</table> | |||
'' | == Function == | ||
[https://www.uniprot.org/uniprot/CA1A_CONEP CA1A_CONEP] Alpha-conotoxins act on postsynaptic membranes, they bind to the nicotinic acetylcholine receptors (nAChR) and thus inhibit them. This native peptide blocks mammalian nicotinic acetylcholine receptors composed of alpha-3-beta-2/CHRNA3-CHRNB2 and alpha-3-beta-4/CHRNA3-CHRNB4 subunits (PubMed:9624161).<ref>PMID:9624161</ref> | |||
<div style="background-color:#fffaf0;"> | |||
== | == Publication Abstract from PubMed == | ||
Conotoxins are valuable probes of receptors and ion channels because of their small size and highly selective activity. alpha-Conotoxin EpI, a 16-residue peptide from the mollusk-hunting Conus episcopatus, has the amino acid sequence GCCSDPRCNMNNPDY(SO3H)C-NH2 and appears to be an extremely potent and selective inhibitor of the alpha3beta2 and alpha3beta4 neuronal subtypes of the nicotinic acetylcholine receptor (nAChR). The desulfated form of EpI ([Tyr15]EpI) has a potency and selectivity for the nAChR receptor similar to those of EpI. Here we describe the crystal structure of [Tyr15]EpI solved at a resolution of 1.1 A using SnB. The asymmetric unit has a total of 284 non-hydrogen atoms, making this one of the largest structures solved de novo by direct methods. The [Tyr15]EpI structure brings to six the number of alpha-conotoxin structures that have been determined to date. Four of these, [Tyr15]EpI, PnIA, PnIB, and MII, have an alpha4/7 cysteine framework and are selective for the neuronal subtype of the nAChR. The structure of [Tyr15]EpI has the same backbone fold as the other alpha4/7-conotoxin structures, supporting the notion that this conotoxin cysteine framework and spacing give rise to a conserved fold. The surface charge distribution of [Tyr15]EpI is similar to that of PnIA and PnIB but is likely to be different from that of MII, suggesting that [Tyr15]EpI and MII may have different binding modes for the same receptor subtype. | Conotoxins are valuable probes of receptors and ion channels because of their small size and highly selective activity. alpha-Conotoxin EpI, a 16-residue peptide from the mollusk-hunting Conus episcopatus, has the amino acid sequence GCCSDPRCNMNNPDY(SO3H)C-NH2 and appears to be an extremely potent and selective inhibitor of the alpha3beta2 and alpha3beta4 neuronal subtypes of the nicotinic acetylcholine receptor (nAChR). The desulfated form of EpI ([Tyr15]EpI) has a potency and selectivity for the nAChR receptor similar to those of EpI. Here we describe the crystal structure of [Tyr15]EpI solved at a resolution of 1.1 A using SnB. The asymmetric unit has a total of 284 non-hydrogen atoms, making this one of the largest structures solved de novo by direct methods. The [Tyr15]EpI structure brings to six the number of alpha-conotoxin structures that have been determined to date. Four of these, [Tyr15]EpI, PnIA, PnIB, and MII, have an alpha4/7 cysteine framework and are selective for the neuronal subtype of the nAChR. The structure of [Tyr15]EpI has the same backbone fold as the other alpha4/7-conotoxin structures, supporting the notion that this conotoxin cysteine framework and spacing give rise to a conserved fold. The surface charge distribution of [Tyr15]EpI is similar to that of PnIA and PnIB but is likely to be different from that of MII, suggesting that [Tyr15]EpI and MII may have different binding modes for the same receptor subtype. | ||
The 1.1 A resolution crystal structure of [Tyr15]EpI, a novel alpha-conotoxin from Conus episcopatus, solved by direct methods.,Hu SH, Loughnan M, Miller R, Weeks CM, Blessing RH, Alewood PF, Lewis RJ, Martin JL Biochemistry. 1998 Aug 18;37(33):11425-33. PMID:9708977<ref>PMID:9708977</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 1a0m" style="background-color:#fffaf0;"></div> | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Conus episcopatus]] | [[Category: Conus episcopatus]] | ||
[[Category: | [[Category: Large Structures]] | ||
[[Category: Alewood | [[Category: Alewood PF]] | ||
[[Category: Blessing | [[Category: Blessing RH]] | ||
[[Category: Hu | [[Category: Hu S-H]] | ||
[[Category: Lewis | [[Category: Lewis RJ]] | ||
[[Category: Loughnan | [[Category: Loughnan M]] | ||
[[Category: Martin | [[Category: Martin JL]] | ||
[[Category: Miller | [[Category: Miller R]] | ||
[[Category: Weeks | [[Category: Weeks CM]] | ||