View source for 1kba


==CRYSTAL STRUCTURE OF KAPPA-BUNGAROTOXIN AT 2.3-ANGSTROM RESOLUTION==
<StructureSection load='1kba' size='340' side='right'caption='[[1kba]], [[Resolution|resolution]] 2.30&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1kba]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Bungarus_multicinctus Bungarus multicinctus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1KBA OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1KBA 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]] 2.3&#8491;</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=1kba FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1kba OCA], [https://pdbe.org/1kba PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1kba RCSB], [https://www.ebi.ac.uk/pdbsum/1kba PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1kba ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/3LKB_BUNMU 3LKB_BUNMU] Postsynaptic neurotoxin that binds and inhibits neuronal nicotinic acetylcholine receptors (nAChR) with high affinity (IC(50)<100 nM). Is a selective, and slowly reversible antagonist of alpha-3/CHRNA3-containing and some alpha-4/CHRNA4-containing AChRs.<ref>PMID:3986193</ref> <ref>PMID:9027980</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/kb/1kba_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=1kba ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
kappa-Neurotoxins display a very low affinity for neuromuscular receptors, but bind tightly to, and inhibit, nicotinic acetylcholine receptors in neuronal tissue such as the chick ciliary ganglia. In contrast, alpha-neurotoxins bind with high affinity and inhibit nicotinic acetylcholine receptors at the neuromuscular junction. The origin of this difference in specificity has been a long-studied question in the field. Here we report the first crystal structure of a kappa-neurotoxin, kappa-bungarotoxin. Unlike the NMR structure previously reported [Sutcliffe, M. J., Dobson, C. M., &amp; Oswald, R. E. (1992) Biochemistry 31, 2962-2970], the present crystal structure more accurately defines the polypeptide fold and the nature of the interaction between subunits in the active dimer, which is a unique feature of the kappa-neurotoxins. The structure has been refined to R = 19.6% with X-ray diffraction data extending to a resolution of 2.3 A. There are two independent protein molecules (66 amino acid residues each) in the asymmetric unit that are arranged as a dimer with the two subunits related by a rotation of 178.6 degrees. Each subunit consists of three main-chain loops. Three of the five beta-strands of each subunit form an antiparallel beta-sheet which becomes an extended six-stranded antiparallel beta-sheet, by virtue of the approximate 2-fold symmetry of the dimer. The interactions at the dimer interface consist of six main-chain-main-chain hydrogen bonds, as well as three other hydrogen-bonding interactions involving side chains.(ABSTRACT TRUNCATED AT 250 WORDS)

Crystal structure of kappa-bungarotoxin at 2.3-A resolution.,Dewan JC, Grant GA, Sacchettini JC Biochemistry. 1994 Nov 8;33(44):13147-54. PMID:7947721<ref>PMID:7947721</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 1kba" style="background-color:#fffaf0;"></div>

==See Also==
*[[Bungarotoxin 3D structures|Bungarotoxin 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Bungarus multicinctus]]
[[Category: Large Structures]]
[[Category: Dewan JC]]
[[Category: Grant GA]]
[[Category: Sacchettini JC]]