title: Synthesis of N-glycan units for assessment of substrate structural requirements of N-acetylglucosaminyltransferase III.
abstract: N-Acetylglucosaminyltransferase (GnT) III is a glycosyltransferase which produces bisected N-glycans by transferring GlcNAc to the 4-position of core mannose. Bisected N-glycans are involved in physiological and pathological processes through the functional regulation of their carrier proteins. An understanding of the biological functions of bisected glycans will be greatly accelerated by use of specific inhibitors of GnT-III. Thus far, however, such inhibitors have not been developed and even the substrate-binding mode of GnT-III is not fully understood. To gain insight into structural features required of the substrate, we systematically synthesized four N-glycan units, the branching parts of the bisected and non-bisected N-glycans. The series of syntheses were achieved from a common core trimannose, giving bisected tetra- and hexasaccharides as well as non-bisected tri- and pentasaccharides. A competitive GnT-III inhibition assay using the synthetic substrates revealed a vital role for the Manβ(1-4)GlcNAc moiety. In keeping with previous reports, GlcNAc at the α1,3-branch is also involved in the interaction. The structural requirements of GnT-III elucidated in this study will provide a basis for rational inhibitor design.
authors.affiliation: Structural Glycobiology Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center for Systems Chemical Biology, RIKEN Global Research Cluster, Wako, Saitama 351-0198, Japan; Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Hanashima
authors.affiliation: Disease Glycomics Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center for Systems Chemical Biology, RIKEN Global Research Cluster, Wako, Saitama 351-0198, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Korekane
authors.affiliation: Disease Glycomics Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center for Systems Chemical Biology, RIKEN Global Research Cluster, Wako, Saitama 351-0198, Japan.
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Taniguchi
authors.affiliation: Structural Glycobiology Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center for Systems Chemical Biology, RIKEN Global Research Cluster, Wako, Saitama 351-0198, Japan. Electronic address: yyoshiki@riken.jp.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Yamaguchi
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D008969:Molecular Sequence Data; D017351:N-Acetylglucosaminyltransferases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011134:Polysaccharides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D013329:Structure-Activity Relationship
chemical_list: D004791:Enzyme Inhibitors; D011134:Polysaccharides; D017351:N-Acetylglucosaminyltransferases; C054599:beta-1,4-mannosyl-glycoprotein beta-1,4-N-acetylglucosaminyltransferase
keywords: Bisecting GlcNAc; Glycosylation; N-Acetylglucosaminyltransferase III; N-Glycan; Synthesis