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| [[Image:1sll.jpg|left|200px]]<br /><applet load="1sll" size="450" color="white" frame="true" align="right" spinBox="true"
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| caption="1sll, resolution 2.0Å" />
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| '''SIALIDASE L FROM LEECH MACROBDELLA DECORA'''<br />
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| ==Overview== | | ==SIALIDASE L FROM LEECH MACROBDELLA DECORA== |
| BACKGROUND: Intramolecular trans-sialidase from leech (Macrobdella decora), is a unique enzyme which cleaves the terminal neuraminic acid (NeuAc), residue from sialoglycoconjugates, releasing 2, 7-anhydro-neuraminic acid, (2,7-anhydro-NeuAc). It is the first enzyme found to exhibit strictly, specific cleavage of NeuAc alpha2-->3Gal linkages in sialoglycoconjugates., The release of 2,7-anhydro-NeuAc instead of NeuAc implies a unique, mechanism, in which the sialosyl linkage is transferred within the, sialoglycoconjugate rather than hydrolyzed. The aims of the structural, study were to gain structural insight into the strict specificity and, unique mechanism of this unusual enzyme. Results:. The 2.0 A crystal, structure of recombinant leech intramolecular trans-sialidase has been, solved by multiple isomorphous replacement. The 1.8 A structure of the, enzyme in complex with 2-deoxy-2, 3-didehydro-NeuAc was also solved. The, refined model comprising residues 81-769 has a catalytic beta-propeller, domain (C), a N-terminal lectin-like domain (II) and an irregular, beta-stranded domain (III) inserted into the catalytic domain. The, structure reveals several possible carbohydrate-binding features: domain, II has a concave face, like that of other sialidases, and there is a, suitable surface charge distribution at the domain III-C interface., CONCLUSIONS: Structural comparisons showed closer evolutionary, relationships to bacterial sialidases than to viral neuraminidases., Mainchain and sidechain atoms around Thr593 make the glycerol-binding, pocket incapable of accommodating an extended equatorial 6-glycerol group, implying that the 6-glycerol group of the reaction intermediate may occupy, an axial position, which is also required by the catalytic mechanism. The, steric hindrance introduced by the bulky sidechain of Trp734 above the, 2-carboxylate group may explain the lack of water involvement in the, cleavage reaction and the substrate specificity.
| | <StructureSection load='1sll' size='340' side='right'caption='[[1sll]], [[Resolution|resolution]] 2.00Å' scene=''> |
| | | == Structural highlights == |
| ==About this Structure== | | <table><tr><td colspan='2'>[[1sll]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Macrobdella_decora Macrobdella decora]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1SLL OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1SLL FirstGlance]. <br> |
| 1SLL is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Macrobdella_decora Macrobdella decora]. Active as [http://en.wikipedia.org/wiki/Exo-alpha-sialidase Exo-alpha-sialidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.18 3.2.1.18] Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1SLL OCA].
| | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2Å</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=1sll FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1sll OCA], [https://pdbe.org/1sll PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1sll RCSB], [https://www.ebi.ac.uk/pdbsum/1sll PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1sll ProSAT]</span></td></tr> |
| ==Reference== | | </table> |
| The crystal structure of an intramolecular trans-sialidase with a NeuAc alpha2-->3Gal specificity., Luo Y, Li SC, Chou MY, Li YT, Luo M, Structure. 1998 Apr 15;6(4):521-30. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=9562562 9562562]
| | == Function == |
| [[Category: Exo-alpha-sialidase]] | | [https://www.uniprot.org/uniprot/NANL_MACDE NANL_MACDE] |
| | == 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/sl/1sll_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=1sll ConSurf]. |
| | <div style="clear:both"></div> |
| | __TOC__ |
| | </StructureSection> |
| | [[Category: Large Structures]] |
| [[Category: Macrobdella decora]] | | [[Category: Macrobdella decora]] |
| [[Category: Single protein]]
| | [[Category: Chou MY]] |
| [[Category: Chou, M.Y.]] | | [[Category: Li SC]] |
| [[Category: Li, S.C.]] | | [[Category: Li YT]] |
| [[Category: Li, Y.T.]] | | [[Category: Luo M]] |
| [[Category: Luo, M.]] | | [[Category: Luo Y]] |
| [[Category: Luo, Y.]] | |
| [[Category: hydrolase]]
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| [[Category: sialidase]]
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| ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Wed Nov 21 02:28:09 2007''
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