View source for 1ws4


==Crystal structure of Jacalin- Me-alpha-Mannose complex: Promiscuity vs Specificity==
<StructureSection load='1ws4' size='340' side='right'caption='[[1ws4]], [[Resolution|resolution]] 1.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1ws4]] is a 8 chain structure with sequence from [https://en.wikipedia.org/wiki/Artocarpus_integer Artocarpus integer]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1WS4 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1WS4 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]] 1.9&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=AMG:ALPHA-METHYL-D-GALACTOSIDE'>AMG</scene>, <scene name='pdbligand=GYP:METHYL-ALPHA-D-GLUCOPYRANOSIDE'>GYP</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=1ws4 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ws4 OCA], [https://pdbe.org/1ws4 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1ws4 RCSB], [https://www.ebi.ac.uk/pdbsum/1ws4 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1ws4 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/LECA_ARTIN LECA_ARTIN] D-galactose-specific lectin, binds the T-antigen structure Gal-beta1,3-GalNAc (Thomsen-Friedenreich-antigen-specific lectin). Potent and selective stimulant of distinct T- and B-cell functions. Shows a unique ability to specifically recognize IgA-1 from human serum.
== 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/ws/1ws4_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=1ws4 ConSurf].
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== Publication Abstract from PubMed ==
Jacalin, a tetrameric lectin, is one of the two lectins present in jackfruit (Artocarpus integrifolia) seeds. Its crystal structure revealed, for the first time, the occurrence of the beta-prism I fold in lectins. The structure led to the elucidation of the crucial role of a new N terminus generated by post-translational proteolysis for the lectin's specificity for galactose. Subsequent X-ray studies on other carbohydrate complexes showed that the extended binding site of jacalin consisted of, in addition to the primary binding site, a hydrophobic secondary site A composed of aromatic residues and a secondary site B involved mainly in water-bridges. A recent investigation involving surface plasmon resonance and the X-ray analysis of a methyl-alpha-mannose complex, had led to a suggestion of promiscuity in the lectin's sugar specificity. To explore this suggestion further, detailed isothermal titration calorimetric studies on the interaction of galactose (Gal), mannose (Man), glucose (Glc), Me-alpha-Gal, Me-alpha-Man, Me-alpha-Glc and other mono- and oligosaccharides of biological relevance and crystallographic studies on the jacalin-Me-alpha-Glc complex and a new form of the jacalin-Me-alpha-Man complex, have been carried out. The binding affinity of Me-alpha-Man is 20 times weaker than that of Me-alpha-Gal. The corresponding number is 27, when the binding affinities of Gal and Me-alpha-Gal, and those of Man and Me-alpha-Man are compared. Glucose (Glc) shows no measurable binding, while the binding affinity of Me-alpha-Glc is slightly less than that of Me-alpha-Man. The available crystal structures of jacalin-sugar complexes provide a convincing explanation for the energetics of binding in terms of interactions at the primary binding site and secondary site A. The other sugars used in calorimetric studies show no detectable binding to jacalin. These results and other available evidence suggest that jacalin is specific to O-glycans and its affinity to N-glycans is extremely weak or non-existent and therefore of limited value in processes involving biological recognition.

Structural basis for the energetics of jacalin-sugar interactions: promiscuity versus specificity.,Arockia Jeyaprakash A, Jayashree G, Mahanta SK, Swaminathan CP, Sekar K, Surolia A, Vijayan M J Mol Biol. 2005 Mar 18;347(1):181-8. Epub 2005 Jan 18. PMID:15733927<ref>PMID:15733927</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Agglutinin 3D structures|Agglutinin 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Artocarpus integer]]
[[Category: Large Structures]]
[[Category: Jayashree G]]
[[Category: Jeyaprakash AA]]
[[Category: Mahanta SK]]
[[Category: Sekar K]]
[[Category: Surolia A]]
[[Category: Vijayan M]]