1kkt: Difference between revisions
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[[Image:1kkt.gif|left|200px]] | [[Image:1kkt.gif|left|200px]] | ||
'''Structure of P. citrinum alpha 1,2-mannosidase reveals the basis for differences in specificity of the ER and Golgi Class I enzymes''' | {{Structure | ||
|PDB= 1kkt |SIZE=350|CAPTION= <scene name='initialview01'>1kkt</scene>, resolution 2.2Å | |||
|SITE= | |||
|LIGAND= <scene name='pdbligand=CA:CALCIUM ION'>CA</scene> | |||
|ACTIVITY= [http://en.wikipedia.org/wiki/Mannosyl-oligosaccharide_1,2-alpha-mannosidase Mannosyl-oligosaccharide 1,2-alpha-mannosidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.113 3.2.1.113] | |||
|GENE= msdC ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=5077 Penicillium citrinum]) | |||
}} | |||
'''Structure of P. citrinum alpha 1,2-mannosidase reveals the basis for differences in specificity of the ER and Golgi Class I enzymes''' | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
1KKT is a [ | 1KKT is a [[Single protein]] structure of sequence from [http://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]. | ||
==Reference== | ==Reference== | ||
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:[http:// | 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:[http://www.ncbi.nlm.nih.gov/pubmed/11714724 11714724] | ||
[[Category: Mannosyl-oligosaccharide 1,2-alpha-mannosidase]] | [[Category: Mannosyl-oligosaccharide 1,2-alpha-mannosidase]] | ||
[[Category: Penicillium citrinum]] | [[Category: Penicillium citrinum]] | ||
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[[Category: (alpha/alpha)7-barrel]] | [[Category: (alpha/alpha)7-barrel]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 12:18:47 2008'' | ||
Revision as of 13:18, 20 March 2008
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| , resolution 2.2Å | |||||||
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| Ligands: | |||||||
| Gene: | msdC (Penicillium citrinum) | ||||||
| Activity: | Mannosyl-oligosaccharide 1,2-alpha-mannosidase, with EC number 3.2.1.113 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Structure of P. citrinum alpha 1,2-mannosidase reveals the basis for differences in specificity of the ER and Golgi Class I enzymes
OverviewOverview
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.
About this StructureAbout this Structure
1KKT is a Single protein structure of sequence from Penicillium citrinum. Full crystallographic information is available from OCA.
ReferenceReference
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
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