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==CRYSTAL STRUCTURE OF PSEUDOMONAS 7A GLUTAMINASE-ASPARAGINASE WITH THE INHIBITOR DON COVALENTLY BOUND IN THE ACTIVE SITE== | |||
<StructureSection load='1djp' size='340' side='right'caption='[[1djp]], [[Resolution|resolution]] 1.90Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[1djp]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Pseudomonas_sp._7A Pseudomonas sp. 7A]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1DJP OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1DJP 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]] 1.9Å</td></tr> | |||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=DO2:5,5-DIHYDROXY-6-OXO-L-NORLEUCINE'>DO2</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=1djp FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1djp OCA], [https://pdbe.org/1djp PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1djp RCSB], [https://www.ebi.ac.uk/pdbsum/1djp PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1djp ProSAT]</span></td></tr> | |||
</table> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/ASPQ_PSES7 ASPQ_PSES7] | |||
== 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/dj/1djp_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=1djp ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Pseudomonas 7A glutaminase-asparaginase (PGA) catalyzes the hydrolysis of D and L isomers of glutamine and asparagine. Crystals of PGA were reacted with diazo analogues of glutamine (6-diazo-5-oxo-L-norleucine, DON) and asparagine (5-diazo-4-oxo-L-norvaline, DONV), which are known inhibitors of the enzyme. The derivatized crystals remained isomorphous to native PGA crystals. Their structures were refined to crystallographic R = 0.20 and R(free) = 0.24 for PGA-DON and R = 0.19 and R = 0.23 for PGA-DONV. Difference Fourier electron density maps clearly showed that both DON and DONV inactivate PGA through covalent inhibition. Continuous electron density connecting the inhibitor to both Thr20 and Tyr34 of the flexible loop was observed providing strong evidence that Thr20 is the primary catalytic nucleophile and that Tyr34 plays an important role in catalysis as well. The unexpected covalent binding observed in the PGA-DON and PGA-DONV complexes shows that a secondary reaction involving the formation of a Tyr34-inhibitor bond takes place with concomitant inactivation of PGA. The predicted covalent linkage is not seen, however, suggesting an alternative method of inhibition not yet seen for these diazo analogues. These surprising results give insight as to the role of the flexible loop Thr and Tyr in the catalytic mechanism. | |||
Reactions of Pseudomonas 7A glutaminase-asparaginase with diazo analogues of glutamine and asparagine result in unexpected covalent inhibitions and suggests an unusual catalytic triad Thr-Tyr-Glu.,Ortlund E, Lacount MW, Lewinski K, Lebioda L Biochemistry. 2000 Feb 15;39(6):1199-204. PMID:10684596<ref>PMID:10684596</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 1djp" style="background-color:#fffaf0;"></div> | |||
== | ==See Also== | ||
[[ | *[[Glutaminase 3D structures|Glutaminase 3D structures]] | ||
== References == | |||
== | <references/> | ||
< | __TOC__ | ||
[[Category: Pseudomonas sp.]] | </StructureSection> | ||
[[Category: Lacount | [[Category: Large Structures]] | ||
[[Category: Lebioda | [[Category: Pseudomonas sp. 7A]] | ||
[[Category: Lewinski | [[Category: Lacount MW]] | ||
[[Category: Ortlund | [[Category: Lebioda L]] | ||
[[Category: Lewinski K]] | |||
[[Category: Ortlund E]] | |||
Latest revision as of 12:35, 25 December 2024
CRYSTAL STRUCTURE OF PSEUDOMONAS 7A GLUTAMINASE-ASPARAGINASE WITH THE INHIBITOR DON COVALENTLY BOUND IN THE ACTIVE SITECRYSTAL STRUCTURE OF PSEUDOMONAS 7A GLUTAMINASE-ASPARAGINASE WITH THE INHIBITOR DON COVALENTLY BOUND IN THE ACTIVE SITE
Structural highlights
FunctionEvolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedPseudomonas 7A glutaminase-asparaginase (PGA) catalyzes the hydrolysis of D and L isomers of glutamine and asparagine. Crystals of PGA were reacted with diazo analogues of glutamine (6-diazo-5-oxo-L-norleucine, DON) and asparagine (5-diazo-4-oxo-L-norvaline, DONV), which are known inhibitors of the enzyme. The derivatized crystals remained isomorphous to native PGA crystals. Their structures were refined to crystallographic R = 0.20 and R(free) = 0.24 for PGA-DON and R = 0.19 and R = 0.23 for PGA-DONV. Difference Fourier electron density maps clearly showed that both DON and DONV inactivate PGA through covalent inhibition. Continuous electron density connecting the inhibitor to both Thr20 and Tyr34 of the flexible loop was observed providing strong evidence that Thr20 is the primary catalytic nucleophile and that Tyr34 plays an important role in catalysis as well. The unexpected covalent binding observed in the PGA-DON and PGA-DONV complexes shows that a secondary reaction involving the formation of a Tyr34-inhibitor bond takes place with concomitant inactivation of PGA. The predicted covalent linkage is not seen, however, suggesting an alternative method of inhibition not yet seen for these diazo analogues. These surprising results give insight as to the role of the flexible loop Thr and Tyr in the catalytic mechanism. Reactions of Pseudomonas 7A glutaminase-asparaginase with diazo analogues of glutamine and asparagine result in unexpected covalent inhibitions and suggests an unusual catalytic triad Thr-Tyr-Glu.,Ortlund E, Lacount MW, Lewinski K, Lebioda L Biochemistry. 2000 Feb 15;39(6):1199-204. PMID:10684596[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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