View source for 2btx


==SOLUTION NMR STRUCTURE OF THE COMPLEX OF ALPHA-BUNGAROTOXIN WITH A LIBRARY DERIVED PEPTIDE, NMR, MINIMIZED AVERAGE STRUCTURE==
<StructureSection load='2btx' size='340' side='right'caption='[[2btx]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2btx]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Bungarus_multicinctus Bungarus multicinctus]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2BTX OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2BTX FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR, 1 model</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=2btx FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2btx OCA], [https://pdbe.org/2btx PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2btx RCSB], [https://www.ebi.ac.uk/pdbsum/2btx PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2btx ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/3L21A_BUNMU 3L21A_BUNMU] Binds with high affinity to muscular (tested on Torpedo marmorata, Kd=0.4 nM) and neuronal (tested on chimeric alpha-7/CHRNA7, Kd=0.95 nM) nicotinic acetylcholine receptor (nAChR) and inhibits acetylcholine from binding to the receptor, thereby impairing neuromuscular and neuronal transmission (PubMed:9305882). It also shows an activity on GABA(A) receptors (PubMed:16549768, PubMed:25634239). It antagonises GABA-activated currents with high potency when tested on primary hippocampal neurons (PubMed:25634239). It inhibits recombinantly expressed GABA(A) receptors composed of alpha-2-beta-2-gamma-2 (GABRA2-GABRB2-GABRG2) subunits with high potency (62.3% inhibition at 20 uM of toxin) (PubMed:25634239). It also shows a weaker inhibition on GABA(A) receptors composed of alpha-1-beta-2-gamma-2 (GABRA1-GABRB2-GABRG2) subunits, alpha-4-beta-2-gamma-2 (GABRA4-GABRB2-GABRG2) subunits, and alpha-5-beta-2-gamma-2 (GABRA5-GABRB2-GABRG2) subunits (PubMed:25634239). A very weak inhibition is also observed on GABA(A) receptor composed of alpha-1-beta-3-gamma-2 (GABRA1-GABRB3-GABRG2) (PubMed:26221036). It has also been shown to bind and inhibit recombinant GABA(A) receptor beta-3/GABRB3 subunit (Kd=about 50 nM) (PubMed:16549768). In addition, it blocks the extracellular increase of dopamine evoked by nicotine only at the higher dose (4.2 uM) (PubMed:9840221).<ref>PMID:16549768</ref> <ref>PMID:25634239</ref> <ref>PMID:9305882</ref> <ref>PMID:9840221</ref> 
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/bt/2btx_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=2btx ConSurf].
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== Publication Abstract from PubMed ==
The solution structure of the complex between alpha-bungarotoxin (alpha-BTX) and a 13-residue library-derived peptide (MRYYESSLKSYPD) has been solved using two-dimensional proton-NMR spectroscopy. The bound peptide adopts an almost-globular conformation resulting from three turns that surround a hydrophobic core formed by Tyr-11 of the peptide. The peptide fills an alpha-BTX pocket made of residues located at fingers I and II, as well as at the C-terminal region. Of the peptide residues, the largest contact area is formed by Tyr-3 and Tyr-4. These findings are in accord with the previous data in which it had been shown that substitution of these aromatic residues by aliphatic amino acids leads to loss of binding of the modified peptide with alpha-BTX. Glu-5 and Leu-8, which also remarkably contribute to the contact area with the toxin, are present in all the library-derived peptides that bind strongly to alpha-BTX. The structure of the complex may explain the fact that the library-derived peptide binds alpha-BTX with a 15-fold higher affinity than that shown by the acetylcholine receptor peptide (alpha185-196). Although both peptides bind to similar sites on alpha-BTX, the latter adopts an extended conformation when bound to the toxin [Basus, V., Song, G. &amp; Hawrot, E. (1993) Biochemistry 32, 12290-12298], whereas the library peptide is nearly globular and occupies a larger surface area of alpha-BTX binding site.

Three-dimensional solution structure of the complex of alpha-bungarotoxin with a library-derived peptide.,Scherf T, Balass M, Fuchs S, Katchalski-Katzir E, Anglister J Proc Natl Acad Sci U S A. 1997 Jun 10;94(12):6059-64. PMID:9177168<ref>PMID:9177168</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 2btx" style="background-color:#fffaf0;"></div>

==See Also==
*[[Bungarotoxin 3D structures|Bungarotoxin 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Bungarus multicinctus]]
[[Category: Large Structures]]
[[Category: Anglister J]]
[[Category: Balass M]]
[[Category: Fuchs S]]
[[Category: Katchalski-Katzir E]]
[[Category: Scherf T]]