1a2a: Difference between revisions

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[[Image:1a2a.gif|left|200px]]<br />
<applet load="1a2a" size="450" color="white" frame="true" align="right" spinBox="true"
caption="1a2a, resolution 2.80&Aring;" />
'''AGKISTROTOXIN, A PHOSPHOLIPASE A2-TYPE PRESYNAPTIC NEUROTOXIN FROM AGKISTRODON HALYS PALLAS'''<br />


==Overview==
==AGKISTROTOXIN, A PHOSPHOLIPASE A2-TYPE PRESYNAPTIC NEUROTOXIN FROM AGKISTRODON HALYS PALLAS==
The crystal structure of agkistrodotoxin containing eight copies of, molecules in the asymmetric unit has been determined at 2.8 A resolution, to a crystallographic R factor of 0.207 by the molecular replacement, technique. Two spatially adjacent regions of agkistrodotoxin molecule, turn 55-61 and stretch 85-91, are remarkably different from those of, non-neurotoxic isoforms in conformation and electrostatic characteristics., These regions are likely to be involved in the recognition of, agkistrodotoxin towards the specific receptor at the presynaptic membrane., The structural comparison of the interfacial recognition site with, non-neurotoxic isoforms reveals a decreased hydrophobicity and lack of, residues with bulky hydrophobic side-chains (i.e. Trp) to serve as, membrane anchors. This structural feature of agkistrodotoxin may be, related to the reduced non-specific binding of the toxin to non-targeted, membrane before it arrives at the presynaptic membrane and recognizes the, putative receptor. A unique hydrophobic patch including residues I19, P20, F21, A23, F24, M118 and F119 is found on the surface of the molecule near, the entrance of the hydrophobic channel which plays an important role in, crystal packing. The interaction mode between the patches might give a, clue to the binding of the neurotoxin on the membrane. The agkistrodotoxin, molecules in the asymmetric unit form two tetramers and each tetramer, exhibits a novel "dimer of dimers"-like structure. A molecule-spanning, four-stranded antiparallel beta-sheet is formed by the beta-wings of two, molecules within a tetramer.
<StructureSection load='1a2a' size='340' side='right'caption='[[1a2a]], [[Resolution|resolution]] 2.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1a2a]] is a 8 chain structure with sequence from [https://en.wikipedia.org/wiki/Gloydius_halys Gloydius halys]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1A2A OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1A2A 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]] 2.8&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</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=1a2a FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1a2a OCA], [https://pdbe.org/1a2a PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1a2a RCSB], [https://www.ebi.ac.uk/pdbsum/1a2a PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1a2a ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/PA2N_GLOHA PA2N_GLOHA] Snake venom phospholipase A2 (PLA2) that inhibits neuromuscular transmission by blocking acetylcholine release from the nerve termini. PLA2 catalyzes the calcium-dependent hydrolysis of the 2-acyl groups in 3-sn-phosphoglycerides.<ref>PMID:15032748</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/a2/1a2a_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=1a2a ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The crystal structure of agkistrodotoxin containing eight copies of molecules in the asymmetric unit has been determined at 2.8 A resolution to a crystallographic R factor of 0.207 by the molecular replacement technique. Two spatially adjacent regions of agkistrodotoxin molecule, turn 55-61 and stretch 85-91, are remarkably different from those of non-neurotoxic isoforms in conformation and electrostatic characteristics. These regions are likely to be involved in the recognition of agkistrodotoxin towards the specific receptor at the presynaptic membrane. The structural comparison of the interfacial recognition site with non-neurotoxic isoforms reveals a decreased hydrophobicity and lack of residues with bulky hydrophobic side-chains (i.e. Trp) to serve as membrane anchors. This structural feature of agkistrodotoxin may be related to the reduced non-specific binding of the toxin to non-targeted membrane before it arrives at the presynaptic membrane and recognizes the putative receptor. A unique hydrophobic patch including residues I19, P20, F21, A23, F24, M118 and F119 is found on the surface of the molecule near the entrance of the hydrophobic channel which plays an important role in crystal packing. The interaction mode between the patches might give a clue to the binding of the neurotoxin on the membrane. The agkistrodotoxin molecules in the asymmetric unit form two tetramers and each tetramer exhibits a novel "dimer of dimers"-like structure. A molecule-spanning four-stranded antiparallel beta-sheet is formed by the beta-wings of two molecules within a tetramer.


==About this Structure==
Crystal structure of agkistrodotoxin, a phospholipase A2-type presynaptic neurotoxin from agkistrodon halys pallas.,Tang L, Zhou YC, Lin ZJ J Mol Biol. 1998 Sep 11;282(1):1-11. PMID:9733637<ref>PMID:9733637</ref>
1A2A is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Gloydius_halys Gloydius halys] with CL as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Phospholipase_A(2) Phospholipase A(2)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.1.4 3.1.1.4] Structure known Active Site: NIC. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1A2A OCA].


==Reference==
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
Crystal structure of agkistrodotoxin, a phospholipase A2-type presynaptic neurotoxin from agkistrodon halys pallas., Tang L, Zhou YC, Lin ZJ, J Mol Biol. 1998 Sep 11;282(1):1-11. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=9733637 9733637]
</div>
<div class="pdbe-citations 1a2a" style="background-color:#fffaf0;"></div>
 
==See Also==
*[[Phospholipase A2 3D structures|Phospholipase A2 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Gloydius halys]]
[[Category: Gloydius halys]]
[[Category: Phospholipase A(2)]]
[[Category: Large Structures]]
[[Category: Single protein]]
[[Category: Lin Z]]
[[Category: Lin, Z.]]
[[Category: Tang L]]
[[Category: Tang, L.]]
[[Category: Zhou Y]]
[[Category: Zhou, Y.]]
[[Category: CL]]
[[Category: hydrolase]]
[[Category: lipid degradation]]
[[Category: phospholipase a2]]
[[Category: presynaptic neurotoxin]]
 
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