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==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='1krf' size='340' side='right'caption='[[1krf]], [[Resolution|resolution]] 2.20Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[1krf]] 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=1KRF OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1KRF 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]] 2.2Å</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=KIF:KIFUNENSINE'>KIF</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=1krf FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1krf OCA], [https://pdbe.org/1krf PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1krf RCSB], [https://www.ebi.ac.uk/pdbsum/1krf PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1krf 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/kr/1krf_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=1krf ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== 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®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 1krf" style="background-color:#fffaf0;"></div> | |||
==See Also== | ==See Also== | ||
*[[Mannosidase|Mannosidase]] | *[[Mannosidase 3D structures|Mannosidase 3D structures]] | ||
== References == | |||
== | <references/> | ||
< | __TOC__ | ||
[[Category: | </StructureSection> | ||
[[Category: Large Structures]] | |||
[[Category: Penicillium citrinum]] | [[Category: Penicillium citrinum]] | ||
[[Category: Herscovics | [[Category: Herscovics A]] | ||
[[Category: Howell | [[Category: Howell PL]] | ||
[[Category: Imberty | [[Category: Imberty A]] | ||
[[Category: Lobsanov | [[Category: Lobsanov YD]] | ||
[[Category: Vallee | [[Category: Vallee F]] | ||
[[Category: Yip | [[Category: Yip P]] | ||
[[Category: Yoshida | [[Category: Yoshida T]] | ||