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==CRYSTAL STRUCTURE OF HUMAN CLASS I ALPHA1,2-MANNOSIDASE IN COMPLEX WITH 1-DEOXYMANNOJIRIMYCIN== | |||
<StructureSection load='1fo2' size='340' side='right' caption='[[1fo2]], [[Resolution|resolution]] 2.38Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[1fo2]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1FO2 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1FO2 FirstGlance]. <br> | |||
</td></tr><tr><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=DMJ:1-DEOXYMANNOJIRIMYCIN'>DMJ</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene><br> | |||
<tr><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1fmi|1fmi]], [[1fo3|1fo3]]</td></tr> | |||
<tr><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Alpha-mannosidase Alpha-mannosidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.24 3.2.1.24] </span></td></tr> | |||
<tr><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1fo2 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1fo2 OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1fo2 RCSB], [http://www.ebi.ac.uk/pdbsum/1fo2 PDBsum]</span></td></tr> | |||
<table> | |||
== Disease == | |||
[[http://www.uniprot.org/uniprot/MA1B1_HUMAN MA1B1_HUMAN]] Defects in MAN1B1 are the cause of mental retardation autosomal recessive type 15 (MRT15) [MIM:[http://omim.org/entry/614202 614202]]. Mental retardation is characterized by significantly below average general intellectual functioning associated with impairments in adaptative behavior and manifested during the developmental period.<ref>PMID:21763484</ref> | |||
== Function == | |||
[[http://www.uniprot.org/uniprot/MA1B1_HUMAN MA1B1_HUMAN]] Involved in glycoprotein quality control targeting of misfolded glycoproteins for degradation. It primarily trims a single alpha-1,2-linked mannose residue from Man(9)GlcNAc(2) to produce Man(8)GlcNAc(2), but at high enzyme concentrations, as found in the ER quality control compartment (ERQC), it further trims the carbohydrates to Man(5-6)GlcNAc(2).<ref>PMID:12090241</ref> <ref>PMID:18003979</ref> | |||
== 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/fo/1fo2_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/chain_selection.php?pdb_ID=2ata ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Endoplasmic reticulum (ER) class I alpha1,2-mannosidase (also known as ER alpha-mannosidase I) is a critical enzyme in the maturation of N-linked oligosaccharides and ER-associated degradation. Trimming of a single mannose residue acts as a signal to target misfolded glycoproteins for degradation by the proteasome. Crystal structures of the catalytic domain of human ER class I alpha1,2-mannosidase have been determined both in the presence and absence of the potent inhibitors kifunensine and 1-deoxymannojirimycin. Both inhibitors bind to the protein at the bottom of the active-site cavity, with the essential calcium ion coordinating the O-2' and O-3' hydroxyls and stabilizing the six-membered rings of both inhibitors in a (1)C(4) conformation. This is the first direct evidence of the role of the calcium ion. The lack of major conformational changes upon inhibitor binding and structural comparisons with the yeast alpha1, 2-mannosidase enzyme-product complex suggest that this class of inverting enzymes has a novel catalytic mechanism. The structures also provide insight into the specificity of this class of enzymes and provide a blueprint for the future design of novel inhibitors that prevent degradation of misfolded proteins in genetic diseases. | |||
Structural basis for catalysis and inhibition of N-glycan processing class I alpha 1,2-mannosidases.,Vallee F, Karaveg K, Herscovics A, Moremen KW, Howell PL J Biol Chem. 2000 Dec 29;275(52):41287-98. PMID:10995765<ref>PMID:10995765</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
==See Also== | ==See Also== | ||
*[[Mannosidase|Mannosidase]] | *[[Mannosidase|Mannosidase]] | ||
== References == | |||
== | <references/> | ||
__TOC__ | |||
</StructureSection> | |||
[[Category: Alpha-mannosidase]] | [[Category: Alpha-mannosidase]] | ||
[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
Revision as of 20:18, 29 September 2014
CRYSTAL STRUCTURE OF HUMAN CLASS I ALPHA1,2-MANNOSIDASE IN COMPLEX WITH 1-DEOXYMANNOJIRIMYCINCRYSTAL STRUCTURE OF HUMAN CLASS I ALPHA1,2-MANNOSIDASE IN COMPLEX WITH 1-DEOXYMANNOJIRIMYCIN
Structural highlights
Disease[MA1B1_HUMAN] Defects in MAN1B1 are the cause of mental retardation autosomal recessive type 15 (MRT15) [MIM:614202]. Mental retardation is characterized by significantly below average general intellectual functioning associated with impairments in adaptative behavior and manifested during the developmental period.[1] Function[MA1B1_HUMAN] Involved in glycoprotein quality control targeting of misfolded glycoproteins for degradation. It primarily trims a single alpha-1,2-linked mannose residue from Man(9)GlcNAc(2) to produce Man(8)GlcNAc(2), but at high enzyme concentrations, as found in the ER quality control compartment (ERQC), it further trims the carbohydrates to Man(5-6)GlcNAc(2).[2] [3] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedEndoplasmic reticulum (ER) class I alpha1,2-mannosidase (also known as ER alpha-mannosidase I) is a critical enzyme in the maturation of N-linked oligosaccharides and ER-associated degradation. Trimming of a single mannose residue acts as a signal to target misfolded glycoproteins for degradation by the proteasome. Crystal structures of the catalytic domain of human ER class I alpha1,2-mannosidase have been determined both in the presence and absence of the potent inhibitors kifunensine and 1-deoxymannojirimycin. Both inhibitors bind to the protein at the bottom of the active-site cavity, with the essential calcium ion coordinating the O-2' and O-3' hydroxyls and stabilizing the six-membered rings of both inhibitors in a (1)C(4) conformation. This is the first direct evidence of the role of the calcium ion. The lack of major conformational changes upon inhibitor binding and structural comparisons with the yeast alpha1, 2-mannosidase enzyme-product complex suggest that this class of inverting enzymes has a novel catalytic mechanism. The structures also provide insight into the specificity of this class of enzymes and provide a blueprint for the future design of novel inhibitors that prevent degradation of misfolded proteins in genetic diseases. Structural basis for catalysis and inhibition of N-glycan processing class I alpha 1,2-mannosidases.,Vallee F, Karaveg K, Herscovics A, Moremen KW, Howell PL J Biol Chem. 2000 Dec 29;275(52):41287-98. PMID:10995765[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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