View source for 1nea


==THREE-DIMENSIONAL SOLUTION STRUCTURE OF A CURAREMIMETIC TOXIN FROM NAJA NIGRICOLLIS VENOM: A PROTON NMR AND MOLECULAR MODELING STUDY==
<StructureSection load='1nea' size='340' side='right'caption='[[1nea]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1nea]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Naja_nigricollis Naja nigricollis]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1NEA OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1NEA FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR, 8 models</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=1nea FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1nea OCA], [https://pdbe.org/1nea PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1nea RCSB], [https://www.ebi.ac.uk/pdbsum/1nea PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1nea ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/3S11_NAJPA 3S11_NAJPA] Binds with high affinity to muscular nicotinic acetylcholine receptors (nAChRs) (tested on Torpedo marmorata AChR, Kd=0.07 nM) and with low affinity to neuronal alpha-7/CHRNA7 nAChRs (tested on chimeric receptor, Kd=3 uM) and inhibit acetylcholine from binding to the receptor, thereby impairing neuromuscular transmission (PubMed:9305882). Produces peripheral paralysis by blocking neuromuscular transmission at the postsynaptic site.<ref>PMID:9305882</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/ne/1nea_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=1nea ConSurf].
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== Publication Abstract from PubMed ==
The solution conformation of toxin alpha from Naja nigricollis (61 amino acids and four disulfides), a snake toxin which specifically blocks the activity of the nicotinic acetylcholine receptor (AcChoR), has been determined using nuclear magnetic resonance spectroscopy and molecular modeling. The solution structures were calculated using 409 distance and 73 dihedral angle restraints. The average atomic rms deviation between the eight refined structures and the mean structure is approximately 0.5 A for the backbone atoms. The overall folding of toxin alpha consists of three major loops which are stabilized by three disulfide bridges and one short C terminal loop stabilized by a fourth disulfide bridge. All the disulfides are grouped in the same region of the molecule, forming a highly constrained structure from which the loops protrude. As predicted, this structure appears to be very similar to the 1.4-A resolution crystal structure of another snake neurotoxin, namely, erabutoxin b from Laticauda semifasciata. The atomic rms deviation for the backbone atoms between the solution and crystal structures is approximately 1.7 A. The minor differences which are observed between the two structures are partly related to the deletion of one residue from the chain of toxin alpha. It is notable that, although the two toxins differ from each other by 16 amino acid substitutions, their side chains have an essentially similar spatial organization. However, most of the side chains which constitute the presumed AcChoR binding site for the curaremimetic toxins are poorly resolved in toxin alpha.(ABSTRACT TRUNCATED AT 250 WORDS)

Three-dimensional solution structure of a curaremimetic toxin from Naja nigricollis venom: a proton NMR and molecular modeling study.,Zinn-Justin S, Roumestand C, Gilquin B, Bontems F, Menez A, Toma F Biochemistry. 1992 Nov 24;31(46):11335-47. PMID:1332755<ref>PMID:1332755</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Naja nigricollis]]
[[Category: Bontems F]]
[[Category: Gilquin B]]
[[Category: Menez A]]
[[Category: Roumestand C]]
[[Category: Toma F]]
[[Category: Zinn-Justin S]]