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| [[Image:2gac.gif|left|200px]]<br />
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| <applet load="2gac" size="450" color="white" frame="true" align="right" spinBox="true"
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| caption="2gac, resolution 2.1Å" />
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| '''T152C MUTANT GLYCOSYLASPARAGINASE FROM FLAVOBACTERIUM MENINGOSEPTICUM'''<br />
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| ==Overview== | | ==T152C MUTANT GLYCOSYLASPARAGINASE FROM FLAVOBACTERIUM MENINGOSEPTICUM== |
| Glycosylasparaginase (GA) is a member of a novel family of N-terminal, nucleophile hydrolases that catalytically use an N-terminal residue as, both a polarizing base and a nucleophile. These enzymes are activated from, a single chain precursor by intramolecular autoproteolysis to yield the, N-terminal nucleophile. A deficiency of GA results in the human genetic, disorder known as aspartylglycosaminuria. In this study, we report the, crystal structure of recombinant GA from Flavobacterium meningosepticum., Similar to the human structure, the bacterial GA forms an, alphabetabetaalpha sandwich. However, some significant differences are, observed between the Flavobacterium and human structures. The active site, of Flavobacterium glycosylasparaginase is in an open conformation when, compared with the human structure. We also describe the structure of a, mutant wherein the N-terminal nucleophile Thr152 is substituted by a, cysteine. In the bacterial GA crystals, we observe a heterotetrameric, structure similar to that found in the human structure, as well as that, observed in solution for eukaryotic glycosylasparaginases. The results, confirm the suitability of the bacterial enzyme as a model to study the, consequences of mutations in aspartylglycosaminuria patients. They also, suggest that further studies are necessary to understand the detail, mechanism of this enzyme. The presence of the heterotetrameric structure, in the crystals is significant because dimerization of precursors has been, suggested in the human enzyme to be a prerequisite to trigger, autoproteolysis.
| | <StructureSection load='2gac' size='340' side='right'caption='[[2gac]], [[Resolution|resolution]] 2.10Å' scene=''> |
| | == Structural highlights == |
| | <table><tr><td colspan='2'>[[2gac]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Elizabethkingia_meningoseptica Elizabethkingia meningoseptica]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2GAC OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2GAC 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='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=2gac FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2gac OCA], [https://pdbe.org/2gac PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2gac RCSB], [https://www.ebi.ac.uk/pdbsum/2gac PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2gac ProSAT]</span></td></tr> |
| | </table> |
| | == Function == |
| | [https://www.uniprot.org/uniprot/ASPG_ELIMR ASPG_ELIMR] Cleaves the GlcNAc-Asn bond which joins oligosaccharides to the peptide of asparagine-linked glycoproteins. Requires that the glycosylated asparagine moiety is not substituted on its N-(R1) and C- (R2) terminus. |
| | == 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/ga/2gac_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=2gac ConSurf]. |
| | <div style="clear:both"></div> |
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| ==About this Structure== | | ==See Also== |
| 2GAC is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Elizabethkingia_meningoseptica Elizabethkingia meningoseptica]. Active as [http://en.wikipedia.org/wiki/N(4)-(beta-N-acetylglucosaminyl)-L-asparaginase N(4)-(beta-N-acetylglucosaminyl)-L-asparaginase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.1.26 3.5.1.26] Structure known Active Site: CAT. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2GAC OCA].
| | *[[Glycosylasparaginase|Glycosylasparaginase]] |
| | | __TOC__ |
| ==Reference==
| | </StructureSection> |
| Crystal structures of Flavobacterium glycosylasparaginase. An N-terminal nucleophile hydrolase activated by intramolecular proteolysis., Guo HC, Xu Q, Buckley D, Guan C, J Biol Chem. 1998 Aug 7;273(32):20205-12. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=9685368 9685368]
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| [[Category: Elizabethkingia meningoseptica]] | | [[Category: Elizabethkingia meningoseptica]] |
| [[Category: N(4)-(beta-N-acetylglucosaminyl)-L-asparaginase]] | | [[Category: Large Structures]] |
| [[Category: Protein complex]]
| | [[Category: Guo H-C]] |
| [[Category: Guo, H.C.]] | | [[Category: Xu Q]] |
| [[Category: Xu, Q.]] | |
| [[Category: autoproteolysis]]
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| [[Category: glycosylasparaginase]]
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| [[Category: mutant]]
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| [[Category: n-terminal nucleophile hydrolase]]
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| ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 18:15:54 2007''
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