View source for 1igx


==Crystal Structure of Eicosapentanoic Acid Bound in the Cyclooxygenase Channel of Prostaglandin Endoperoxide H Synthase-1.==
<StructureSection load='1igx' size='340' side='right'caption='[[1igx]], [[Resolution|resolution]] 3.10&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1igx]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Ovis_aries Ovis aries]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1IGX OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1IGX 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]] 3.1&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=BGC:BETA-D-GLUCOSE'>BGC</scene>, <scene name='pdbligand=BMA:BETA-D-MANNOSE'>BMA</scene>, <scene name='pdbligand=BOG:B-OCTYLGLUCOSIDE'>BOG</scene>, <scene name='pdbligand=EPA:5,8,11,14,17-EICOSAPENTAENOIC+ACID'>EPA</scene>, <scene name='pdbligand=MAN:ALPHA-D-MANNOSE'>MAN</scene>, <scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene>, <scene name='pdbligand=NDG:2-(ACETYLAMINO)-2-DEOXY-A-D-GLUCOPYRANOSE'>NDG</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=1igx FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1igx OCA], [https://pdbe.org/1igx PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1igx RCSB], [https://www.ebi.ac.uk/pdbsum/1igx PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1igx ProSAT]</span></td></tr>
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== Function ==
[https://www.uniprot.org/uniprot/PGH1_SHEEP PGH1_SHEEP] May play an important role in regulating or promoting cell proliferation in some normal and neoplastically transformed cells.
== 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/ig/1igx_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=1igx ConSurf].
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== Publication Abstract from PubMed ==
Prostaglandin endoperoxide H synthases-1 and -2 (PGHSs) can oxygenate 18-22 carbon polyunsaturated fatty acids, albeit with varying efficiencies. Here we report the crystal structures of eicosapentaenoic acid (EPA, 20:5 n-3) and linoleic acid (LA, 18:2 n-6) bound in the cyclooxygenase active site of Co(3+) protoporphyrin IX-reconstituted ovine PGHS-1 (Co(3+)-oPGHS-1) and compare the effects of active site substitutions on the rates of oxygenation of EPA, LA, and arachidonic acid (AA). Both EPA and LA bind in the active site with orientations similar to those seen previously with AA and dihomo-gamma-linolenic acid (DHLA). For EPA, the presence of an additional double bond (C-17/C-18) causes this substrate to bind in a "strained" conformation in which C-13 is misaligned with respect to Tyr-385, the residue that abstracts hydrogen from substrate fatty acids. Presumably, this misalignment is responsible for the low rate of EPA oxygenation. For LA, the carboxyl half binds in a more extended configuration than AA, which results in positioning C-11 next to Tyr-385. Val-349 and Ser-530, recently identified as important determinants for efficient oxygenation of DHLA by PGHS-1, play similar roles in the oxygenation of EPA and LA. Approximately 750- and 175-fold reductions in the oxygenation efficiency of EPA and LA were observed with V349A oPGHS-1, compared with a 2-fold change for AA. Val-349 contacts C-2 and C-3 of EPA and C-4 of LA orienting the carboxyl halves of these substrates so that the omega-ends are aligned properly for hydrogen abstraction. An S530T substitution decreases the V(max)/K(m) of EPA and LA by 375- and 140-fold. Ser-530 makes six contacts with EPA and four with LA involving C-8 through C-16; these interactions influence the alignment of the substrate for hydrogen abstraction. Interestingly, replacement of Phe-205 increases the volume of the cyclooxygenase site allowing EPA to be oxygenated more efficiently than with native oPGHS-1.

Structure of eicosapentaenoic and linoleic acids in the cyclooxygenase site of prostaglandin endoperoxide H synthase-1.,Malkowski MG, Thuresson ED, Lakkides KM, Rieke CJ, Micielli R, Smith WL, Garavito RM J Biol Chem. 2001 Oct 5;276(40):37547-55. Epub 2001 Jul 27. PMID:11477109<ref>PMID:11477109</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 1igx" style="background-color:#fffaf0;"></div>

==See Also==
*[[Cyclooxygenase 3D structures|Cyclooxygenase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Ovis aries]]
[[Category: Garavito RM]]
[[Category: Malkowski MG]]
[[Category: Smith WL]]
[[Category: Thuresson ED]]