View source for 1rir


==Crystal structure of meso-tetrasulphonatophenylporphyrin in complex with Peanut lectin.==
<StructureSection load='1rir' size='340' side='right'caption='[[1rir]], [[Resolution|resolution]] 2.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1rir]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Arachis_hypogaea Arachis hypogaea]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1RIR OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1RIR 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]] 2.9&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=MN:MANGANESE+(II)+ION'>MN</scene>, <scene name='pdbligand=SFP:5,10,15,20-TETRAKIS(4-SULPFONATOPHENYL)-21H,23H-PORPHINE'>SFP</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=1rir FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1rir OCA], [https://pdbe.org/1rir PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1rir RCSB], [https://www.ebi.ac.uk/pdbsum/1rir PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1rir ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/LECG_ARAHY LECG_ARAHY] D-galactose specific lectin.
== 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/ri/1rir_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=1rir ConSurf].
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== Publication Abstract from PubMed ==
The extraordinary recognition specificity of lectins for carbohydrate ligands appears to be violated as they also bind to porphyrins and other noncarbohydrate ligands. In this study, crystal structures of meso-tetrasulfonatophenylporphyrin (H(2)TPPS) bound to peanut agglutinin (PNA) in the presence and absence of lactose were determined. The binding of H(2)TPPS with PNA involved 11 molecules of H(2)TPPS in different supramolecular stacking arrangements associated with a tetramer of PNA in the crystals of the PNA-H(2)TPPS binary complex as well as the PNA-H(2)TPPS-lactose ternary complex. The ternary complex involved lactose binding only to two subunits of the PNA tetramer, which did not have porphyrin interacting in the vicinity of the carbohydrate-binding site. Comparison of the two structures highlighted the plasticity of the carbohydrate-binding site expressed in terms of the conformational change in lactose binding. The unusual quaternary structure of PNA, which results in exposed protein-protein interaction sites, might be responsible for the porphyrin binding. The association of porphyrin in diverse oligomeric stacking arrangements observed in the PNA-H(2)TPPS complex suggested the possibility of protein-porphyrin aggregation under abnormal physiological conditions. The structures described here provide a possible native conformation of the carbohydrate-binding site of PNA in the absence of the ligand, highlight mapping of the unsaturated binding surfaces of PNA using porphyrin interactions, indicate new leads toward possible application of this lectin in photodynamic therapy, and exhibit diverse modes of porphyrin-lectin interactions with implications to porphyria, a disease that results from abnormal accumulation of porphyrins.

Crystal structures of the PNA-porphyrin complex in the presence and absence of lactose: mapping the conformational changes on lactose binding, interacting surfaces, and supramolecular aggregations.,Goel M, Damai RS, Sethi DK, Kaur KJ, Maiya BG, Swamy MJ, Salunke DM Biochemistry. 2005 Apr 19;44(15):5588-96. PMID:15823017<ref>PMID:15823017</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 1rir" style="background-color:#fffaf0;"></div>

==See Also==
*[[Galactose-binding lectin|Galactose-binding lectin]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Arachis hypogaea]]
[[Category: Large Structures]]
[[Category: Goel M]]
[[Category: Kaur KJ]]
[[Category: Maiya BG]]
[[Category: Salunke DM]]
[[Category: Swamy MJ]]