1h19: Difference between revisions
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== | ==STRUCTURE OF [E271Q]LEUKOTRIENE A4 HYDROLASE== | ||
<StructureSection load='1h19' size='340' side='right'caption='[[1h19]], [[Resolution|resolution]] 2.10Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[1h19]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1H19 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1H19 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]] 2.1Å</td></tr> | |||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ACY:ACETIC+ACID'>ACY</scene>, <scene name='pdbligand=IMD:IMIDAZOLE'>IMD</scene>, <scene name='pdbligand=YB:YTTERBIUM+(III)+ION'>YB</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</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=1h19 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1h19 OCA], [https://pdbe.org/1h19 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1h19 RCSB], [https://www.ebi.ac.uk/pdbsum/1h19 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1h19 ProSAT]</span></td></tr> | |||
</table> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/LKHA4_HUMAN LKHA4_HUMAN] Epoxide hydrolase that catalyzes the final step in the biosynthesis of the proinflammatory mediator leukotriene B4. Has also aminopeptidase activity.<ref>PMID:1897988</ref> <ref>PMID:1975494</ref> <ref>PMID:2244921</ref> <ref>PMID:12207002</ref> <ref>PMID:11917124</ref> <ref>PMID:15078870</ref> <ref>PMID:18804029</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/h1/1h19_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=1h19 ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Leukotriene A(4) hydrolase/aminopeptidase is a bifunctional zinc metalloenzyme that converts the fatty acid epoxide leukotriene A(4) into leukotriene B(4), a potent chemoattractant and immune-modulating lipid mediator. Recently, the structure of leukotriene A(4) hydrolase revealed that Glu-271, which belongs to a conserved GXMEN motif in the M1 family of zinc peptidases, and Gln-136 are located at the active site. Here we report that mutagenetic replacements of Glu-271, but not Gln-136, abrogate both catalytic activities of leukotriene A(4) hydrolase. Furthermore, the 2.1 A crystal structure of [E271Q]leukotriene A(4) hydrolase revealed minimal conformational changes that could not explain the loss of enzyme function. We propose that the carboxylate of Glu-271 participates in an acid-induced opening of the epoxide moiety of leukotriene A(4) and formation of a carbocation intermediate. Moreover, Glu-271 appears to act as an N-terminal recognition site and may potentially stabilize the transition-state during turnover of peptides, a property that most likely pertains to all members of the M1 family of zinc aminopeptidases. Hence, Glu-271 is a unique example of an amino acid, which has dual and separate functions in two different catalytic reactions, involving lipid and peptide substrates, respectively. | Leukotriene A(4) hydrolase/aminopeptidase is a bifunctional zinc metalloenzyme that converts the fatty acid epoxide leukotriene A(4) into leukotriene B(4), a potent chemoattractant and immune-modulating lipid mediator. Recently, the structure of leukotriene A(4) hydrolase revealed that Glu-271, which belongs to a conserved GXMEN motif in the M1 family of zinc peptidases, and Gln-136 are located at the active site. Here we report that mutagenetic replacements of Glu-271, but not Gln-136, abrogate both catalytic activities of leukotriene A(4) hydrolase. Furthermore, the 2.1 A crystal structure of [E271Q]leukotriene A(4) hydrolase revealed minimal conformational changes that could not explain the loss of enzyme function. We propose that the carboxylate of Glu-271 participates in an acid-induced opening of the epoxide moiety of leukotriene A(4) and formation of a carbocation intermediate. Moreover, Glu-271 appears to act as an N-terminal recognition site and may potentially stabilize the transition-state during turnover of peptides, a property that most likely pertains to all members of the M1 family of zinc aminopeptidases. Hence, Glu-271 is a unique example of an amino acid, which has dual and separate functions in two different catalytic reactions, involving lipid and peptide substrates, respectively. | ||
Leukotriene A4 hydrolase/aminopeptidase. Glutamate 271 is a catalytic residue with specific roles in two distinct enzyme mechanisms.,Rudberg PC, Tholander F, Thunnissen MM, Haeggstrom JZ J Biol Chem. 2002 Jan 11;277(2):1398-404. Epub 2001 Oct 23. PMID:11675384<ref>PMID:11675384</ref> | |||
== | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | ||
Leukotriene A4 | </div> | ||
<div class="pdbe-citations 1h19" style="background-color:#fffaf0;"></div> | |||
==See Also== | |||
*[[Leukotriene A4 Hydrolase|Leukotriene A4 Hydrolase]] | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
[[Category: | [[Category: Large Structures]] | ||
[[Category: Haeggstrom JZ]] | |||
[[Category: Haeggstrom | [[Category: Rudberg PC]] | ||
[[Category: Rudberg | [[Category: Tholander F]] | ||
[[Category: Tholander | [[Category: Thunnissen MMGM]] | ||
[[Category: Thunnissen | |||