View source for 1kkt


==Structure of P. citrinum alpha 1,2-mannosidase reveals the basis for differences in specificity of the ER and Golgi Class I enzymes==
<StructureSection load='1kkt' size='340' side='right'caption='[[1kkt]], [[Resolution|resolution]] 2.20&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1kkt]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Penicillium_citrinum Penicillium citrinum]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1KKT OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1KKT 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]] 2.2&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=MAN:ALPHA-D-MANNOSE'>MAN</scene>, <scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</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=1kkt FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1kkt OCA], [https://pdbe.org/1kkt PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1kkt RCSB], [https://www.ebi.ac.uk/pdbsum/1kkt PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1kkt ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/MAN12_PENCI MAN12_PENCI] Involved in the maturation of Asn-linked oligosaccharides. Progressively trim alpha-1,2-linked mannose residues from Man(9)GlcNAc(2) to produce Man(5)GlcNAc(2).
== 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/kk/1kkt_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=1kkt ConSurf].
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== Publication Abstract from PubMed ==
Class I alpha1,2-mannosidases (glycosylhydrolase family 47) are key enzymes in the maturation of N-glycans. This protein family includes two distinct enzymatically active subgroups. Subgroup 1 includes the yeast and human endoplasmic reticulum (ER) alpha1,2-mannosidases that primarily trim Man(9)GlcNAc(2) to Man(8)GlcNAc(2) isomer B whereas subgroup 2 includes mammalian Golgi alpha1,2-mannosidases IA, IB, and IC that trim Man(9)GlcNAc(2) to Man(5)GlcNAc(2) via Man(8)GlcNAc(2) isomers A and C. The structure of the catalytic domain of the subgroup 2 alpha1,2-mannosidase from Penicillium citrinum has been determined by molecular replacement at 2.2-A resolution. The fungal alpha1,2-mannosidase is an (alphaalpha)(7)-helix barrel, very similar to the subgroup 1 yeast (Vallee, F., Lipari, F., Yip, P., Sleno, B., Herscovics, A., and Howell, P. L. (2000) EMBO J. 19, 581-588) and human (Vallee, F., Karaveg, K., Herscovics, A., Moremen, K. W., and Howell, P. L. (2000) J. Biol. Chem. 275, 41287-41298) ER enzymes. The location of the conserved acidic residues of the catalytic site and the binding of the inhibitors, kifunensine and 1-deoxymannojirimycin, to the essential calcium ion are conserved in the fungal enzyme. However, there are major structural differences in the oligosaccharide binding site between the two alpha1,2-mannosidase subgroups. In the subgroup 1 enzymes, an arginine residue plays a critical role in stabilizing the oligosaccharide substrate. In the fungal alpha1,2-mannosidase this arginine is replaced by glycine. This replacement and other sequence variations result in a more spacious carbohydrate binding site. Modeling studies of interactions between the yeast, human and fungal enzymes with different Man(8)GlcNAc(2) isomers indicate that there is a greater degree of freedom to bind the oligosaccharide in the active site of the fungal enzyme than in the yeast and human ER alpha1,2-mannosidases.

Structure of Penicillium citrinum alpha 1,2-mannosidase reveals the basis for differences in specificity of the endoplasmic reticulum and Golgi class I enzymes.,Lobsanov YD, Vallee F, Imberty A, Yoshida T, Yip P, Herscovics A, Howell PL J Biol Chem. 2002 Feb 15;277(7):5620-30. Epub 2001 Nov 19. PMID:11714724<ref>PMID:11714724</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 1kkt" style="background-color:#fffaf0;"></div>

==See Also==
*[[Mannosidase 3D structures|Mannosidase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Penicillium citrinum]]
[[Category: Herscovics A]]
[[Category: Howell PL]]
[[Category: Imberty A]]
[[Category: Lobsanov YD]]
[[Category: Vallee F]]
[[Category: Yip P]]
[[Category: Yoshida T]]