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Structure type: oligomer
Trivial name: GnM5X
Contained glycoepitopes: IEDB_114701,IEDB_123886,IEDB_123887,IEDB_130701,IEDB_135813,IEDB_137340,IEDB_137485,IEDB_1394182,IEDB_140116,IEDB_141793,IEDB_141807,IEDB_141828,IEDB_144983,IEDB_145668,IEDB_148491,IEDB_148492,IEDB_151079,IEDB_151531,IEDB_152206,IEDB_153212,IEDB_153220,IEDB_164174,IEDB_167188,IEDB_174332,IEDB_187201,IEDB_429156,IEDB_548907,IEDB_857734,IEDB_983930,SB_197,SB_198,SB_33,SB_44,SB_67,SB_72,SB_73,SB_74,SB_77,SB_85

• Article ID: 10936
  Kajiura H, Okamoto T, Misaki R, Matsuura Y, Fujiyama K "Arabidopsis β1,2-xylosyltransferase: substrate specificity and participation in the plant-specific N-glycosylation pathway" - Journal of Bioscience and Bioengineering 113 (2012) 48-54
  

  β1,2-Xylosyltransferase (XYLT) is a plant-specific glycosyltransferase that contributes to the biosynthesis of N-glycoproteins in plants. However, the specificity of XYLT for N-glycans has not yet been completely clarified. To gain insights into the function of XYLT in the plant N-glycosylation pathway, we examined the acceptor substrate specificity of recombinant Arabidopsis XYLT (AtXYLT) using 2-aminopyridine-labeled N-glycans as the substrates and confirmed the N-glycans of Arabidopsis xylt mutant. Recombinant AtXYLT expressed in insect cells required the β1,2-linked N-acetylglucosamine (GlcNAc) residue at the nonreducing terminus of the α1,3-branched mannose (Man) residue (GlcNAcβ1,2-Manα1,3-Man; GNM3B) for activity. However, AtXYLT showed decreased activity with substrates that contained α1,3-fucose at the chitobiose core-GlcNAc or a terminal GlcNAc at the α1,6-branched Man residue of GlcNAcβ1,2-Man (GlcNAcβ1,2-Manα1,6-Man; GNM3A), whose ratios were 10% and 50% of the optimal substrate, GNM3B, respectively. Moreover, AtXYLT did not show any activity in the transfer of the Xyl residue to N-glycans that contained a mammalian-type β1,4-linked galactose (Gal) residue at the nonreducing terminus of GlcNAcβ1,2-Man. These results indicate that a β1,2-linked GlcNAc residue at the nonreducing terminus of an α1,3-branched Man residue is necessary for AtXYLT activity and that mammalian-type β1,4-linked Gal residue(s) on the same branch completely inhibit(s) the activity. Furthermore, N-glycan analysis showed that approximately 30% of the N-glycans carry the Xyl residue in the wild type. These findings suggest that AtXYLT acts on protein-bound N-glycans prior to α1,3-fucosyltransferase and mannosidase II in planta.

  N-glycan, plant N-glycosylation, Arabidopsis β1, 2-xylosyltransferase, β1, 2-xylosylation, baculovirus

  Publication DOI: 10.1016/j.jbiosc.2011.09.011
  Journal NLM ID: 100888800
  Publisher: Osaka, Japan, Amsterdam, The Netherlands: Society for Bioscience and Bioengineering
  Correspondence: fujiyama@icb.osaka-u.ac.jp
  Institutions: International Center for Biotechnology, Osaka University, 2-1 Yamadaoka, Suita-shi, Osaka 565-0871, Japan, Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita-shi, Osaka 565-0871, Japan
  Methods: biological assays, HPLC, LC-MS/MS, genetic manipulations
  
   
  
  Arabidopsis thaliana
  CSDB ID 61026 (all data & tools)