2aec: Difference between revisions
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'''Crystal Structure of Human M340H-Beta1,4-Galactosyltransferase-I (M340H-B4GAL-T1) in Complex with GlcNAc-beta1,2-Man-alpha1,6-Man-beta-OR'''<br /> | '''Crystal Structure of Human M340H-Beta1,4-Galactosyltransferase-I (M340H-B4GAL-T1) in Complex with GlcNAc-beta1,2-Man-alpha1,6-Man-beta-OR'''<br /> | ||
==Overview== | ==Overview== | ||
beta-1,4-Galactosyltransferase-I (beta4Gal-T1) transfers galactose from | beta-1,4-Galactosyltransferase-I (beta4Gal-T1) transfers galactose from UDP-galactose to N-acetylglucosamine (GlcNAc) residues of the branched N-linked oligosaccharide chains of glycoproteins. In an N-linked biantennary oligosaccharide chain, one antenna is attached to the 3-hydroxyl-(1,3-arm), and the other to the 6-hydroxyl-(1,6-arm) group of mannose, which is beta-1,4-linked to an N-linked chitobiose, attached to the aspargine residue of a protein. For a better understanding of the branch specificity of beta4Gal-T1 towards the GlcNAc residues of N-glycans, we have carried out kinetic and crystallographic studies with the wild-type human beta4Gal-T1 (h-beta4Gal-T1) and the mutant Met340His-beta4Gal-T1 (h-M340H-beta4Gal-T1) in complex with a GlcNAc-containing pentasaccharide and several GlcNAc-containing trisaccharides present in N-glycans. The oligosaccharides used were: pentasaccharide GlcNAcbeta1,2-Manalpha1,6 (GlcNAcbeta1,2-Manalpha1,3)Man; the 1,6-arm trisaccharide, GlcNAcbeta1,2-Manalpha1,6-Manbeta-OR (1,2-1,6-arm); the 1,3-arm trisaccharides, GlcNAcbeta1,2-Manalpha1,3-Manbeta-OR (1,2-1,3-arm) and GlcNAcbeta1,4-Manalpha1,3-Manbeta-OR (1,4-1,3-arm); and the trisaccharide GlcNAcbeta1,4-GlcNAcbeta1,4-GlcNAc (chitotriose). With the wild-type h-beta4Gal-T1, the K(m) of 1,2-1,6-arm is approximately tenfold lower than for 1,2-1,3-arm and 1,4-1,3-arm, and 22-fold lower than for chitotriose. Crystal structures of h-M340H-beta4Gal-T1 in complex with the pentasaccharide and various trisaccharides at 1.9-2.0A resolution showed that beta4Gal-T1 is in a closed conformation with the oligosaccharide bound to the enzyme, and the 1,2-1,6-arm trisaccharide makes the maximum number of interactions with the enzyme, which is in concurrence with the lowest K(m) for the trisaccharide. Present studies suggest that beta4Gal-T1 interacts preferentially with the 1,2-1,6-arm trisaccharide rather than with the 1,2-1,3-arm or 1,4-1,3-arm of a bi- or tri-antennary oligosaccharide chain of N-glycan. | ||
==Disease== | ==Disease== | ||
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==About this Structure== | ==About this Structure== | ||
2AEC is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with MN, SO4, UDH, DIO, MES and GOL as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/N-acetyllactosamine_synthase N-acetyllactosamine synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.1.90 2.4.1.90] Full crystallographic information is available from [http:// | 2AEC is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with <scene name='pdbligand=MN:'>MN</scene>, <scene name='pdbligand=SO4:'>SO4</scene>, <scene name='pdbligand=UDH:'>UDH</scene>, <scene name='pdbligand=DIO:'>DIO</scene>, <scene name='pdbligand=MES:'>MES</scene> and <scene name='pdbligand=GOL:'>GOL</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/N-acetyllactosamine_synthase N-acetyllactosamine synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.1.90 2.4.1.90] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2AEC OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Boeggeman, E.]] | [[Category: Boeggeman, E.]] | ||
[[Category: Qasba, P | [[Category: Qasba, P K.]] | ||
[[Category: Ramakrishnan, B.]] | [[Category: Ramakrishnan, B.]] | ||
[[Category: Ramasamy, V.]] | [[Category: Ramasamy, V.]] | ||
[[Category: Ratner, D | [[Category: Ratner, D M.]] | ||
[[Category: Seeberger, P | [[Category: Seeberger, P H.]] | ||
[[Category: DIO]] | [[Category: DIO]] | ||
[[Category: GOL]] | [[Category: GOL]] | ||
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[[Category: beta1]] | [[Category: beta1]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:26:32 2008'' | ||
Revision as of 17:26, 21 February 2008
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Crystal Structure of Human M340H-Beta1,4-Galactosyltransferase-I (M340H-B4GAL-T1) in Complex with GlcNAc-beta1,2-Man-alpha1,6-Man-beta-OR
OverviewOverview
beta-1,4-Galactosyltransferase-I (beta4Gal-T1) transfers galactose from UDP-galactose to N-acetylglucosamine (GlcNAc) residues of the branched N-linked oligosaccharide chains of glycoproteins. In an N-linked biantennary oligosaccharide chain, one antenna is attached to the 3-hydroxyl-(1,3-arm), and the other to the 6-hydroxyl-(1,6-arm) group of mannose, which is beta-1,4-linked to an N-linked chitobiose, attached to the aspargine residue of a protein. For a better understanding of the branch specificity of beta4Gal-T1 towards the GlcNAc residues of N-glycans, we have carried out kinetic and crystallographic studies with the wild-type human beta4Gal-T1 (h-beta4Gal-T1) and the mutant Met340His-beta4Gal-T1 (h-M340H-beta4Gal-T1) in complex with a GlcNAc-containing pentasaccharide and several GlcNAc-containing trisaccharides present in N-glycans. The oligosaccharides used were: pentasaccharide GlcNAcbeta1,2-Manalpha1,6 (GlcNAcbeta1,2-Manalpha1,3)Man; the 1,6-arm trisaccharide, GlcNAcbeta1,2-Manalpha1,6-Manbeta-OR (1,2-1,6-arm); the 1,3-arm trisaccharides, GlcNAcbeta1,2-Manalpha1,3-Manbeta-OR (1,2-1,3-arm) and GlcNAcbeta1,4-Manalpha1,3-Manbeta-OR (1,4-1,3-arm); and the trisaccharide GlcNAcbeta1,4-GlcNAcbeta1,4-GlcNAc (chitotriose). With the wild-type h-beta4Gal-T1, the K(m) of 1,2-1,6-arm is approximately tenfold lower than for 1,2-1,3-arm and 1,4-1,3-arm, and 22-fold lower than for chitotriose. Crystal structures of h-M340H-beta4Gal-T1 in complex with the pentasaccharide and various trisaccharides at 1.9-2.0A resolution showed that beta4Gal-T1 is in a closed conformation with the oligosaccharide bound to the enzyme, and the 1,2-1,6-arm trisaccharide makes the maximum number of interactions with the enzyme, which is in concurrence with the lowest K(m) for the trisaccharide. Present studies suggest that beta4Gal-T1 interacts preferentially with the 1,2-1,6-arm trisaccharide rather than with the 1,2-1,3-arm or 1,4-1,3-arm of a bi- or tri-antennary oligosaccharide chain of N-glycan.
DiseaseDisease
Known diseases associated with this structure: Congenital disorder of glycosylation, type IId OMIM:[137060]
About this StructureAbout this Structure
2AEC is a Single protein structure of sequence from Homo sapiens with , , , , and as ligands. Active as N-acetyllactosamine synthase, with EC number 2.4.1.90 Full crystallographic information is available from OCA.
ReferenceReference
Oligosaccharide preferences of beta1,4-galactosyltransferase-I: crystal structures of Met340His mutant of human beta1,4-galactosyltransferase-I with a pentasaccharide and trisaccharides of the N-glycan moiety., Ramasamy V, Ramakrishnan B, Boeggeman E, Ratner DM, Seeberger PH, Qasba PK, J Mol Biol. 2005 Oct 14;353(1):53-67. PMID:16157350
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