View source for 1abr


==CRYSTAL STRUCTURE OF ABRIN-A==
<StructureSection load='1abr' size='340' side='right'caption='[[1abr]], [[Resolution|resolution]] 2.14&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1abr]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Abrpr Abrpr]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1ABR OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1ABR FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=BGC:BETA-D-GLUCOSE'>BGC</scene>, <scene name='pdbligand=BMA:BETA-D-MANNOSE'>BMA</scene>, <scene name='pdbligand=MAN:ALPHA-D-MANNOSE'>MAN</scene>, <scene name='pdbligand=NDG:2-(ACETYLAMINO)-2-DEOXY-A-D-GLUCOPYRANOSE'>NDG</scene>, <scene name='pdbligand=NGZ:2-(ACETYLAMINO)-2-DEOXY-ALPHA-L-GLUCOPYRANOSE'>NGZ</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1abr FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1abr OCA], [http://pdbe.org/1abr PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1abr RCSB], [http://www.ebi.ac.uk/pdbsum/1abr PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1abr ProSAT]</span></td></tr>
</table>
== Function ==
[[http://www.uniprot.org/uniprot/ABRA_ABRPR ABRA_ABRPR]] The A chain is responsible for inhibiting protein synthesis through the catalytic inactivation of 60S ribosomal subunits by removing adenine from position 4,324 of 28S rRNA. Abrin-a is more toxic than ricin.  The B chain is a galactose-specific lectin that facilitates the binding of abrin to the cell membrane that precedes endocytosis. 
== 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/ab/1abr_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.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=1abr ConSurf].
<div style="clear:both"></div>
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== Publication Abstract from PubMed ==
The crystal structure of abrin-a, a type II ribosome-inactivating protein from the seeds of Abrus precatorius, has been determined from a novel crystalline form by the molecular replacement method using the coordinates of ricin. The structure has been refined at 2.14 A to a R-factor of 18.9%. The root-mean-square deviations of bond lengths and angles from the standard values are 0.013 A and 1.82 degrees, respectively. The overall protein folding is similar to that of ricin, but there are differences in the secondary structure, mostly of the A-chain. Several parts of the molecular surface differ significantly; some of them are quite near the active site cleft, and probably influence ribosome recognition. The positions of invariant active site residues remain the same, except the position of Tyr74. Two water molecules of hydrogen-bonded active site residues have been located in the active site cleft. Both of them may be responsible for hydrolyzing the N-C glycosidic bond. The current abrin-a structure is lactose free; this is probably essential for abrin-a crystallization. The B-chain is a glycoprotein, and the positions of several sugar residues of two sugar chains linked to earlier predicted glycosylation sites were determined. One of the sugar chains is a bridge between two neighboring molecules, since one of its mannose residues is connected to the galactose binding site of the neighboring molecule. Another sugar chain covers the surface of the B-chain.

Crystal structure of abrin-a at 2.14 A.,Tahirov TH, Lu TH, Liaw YC, Chen YL, Lin JY J Mol Biol. 1995 Jul 14;250(3):354-67. PMID:7608980<ref>PMID:7608980</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 1abr" style="background-color:#fffaf0;"></div>

==See Also==
*[[Abrin|Abrin]]
*[[Abrin 3D structures|Abrin 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Abrpr]]
[[Category: Large Structures]]
[[Category: Chu, S C]]
[[Category: Liaw, Y C]]
[[Category: Lin, J Y]]
[[Category: Lu, T H]]
[[Category: Tahirov, T H]]
[[Category: Glycoprotein]]
[[Category: Glycosidase-carbohydrate complex]]
[[Category: Lectin]]
[[Category: Plant seed protein]]
[[Category: Plant toxin]]
[[Category: Protein synthesis inhibitor]]
[[Category: Toxin]]