title: Synthesis of misfolded glycoprotein dimers through native chemical ligation of a dimeric peptide thioester.
abstract: Glycoprotein quality control processes are very important for an efficient production of glycoproteins and for avoiding the accumulation of unwanted toxic species in cells. These complex processes consist of multiple enzymes and chaperones such as UGGT, calnexin/calreticulin, and glucosidase II. We designed and synthesized monomeric and dimeric misfolded glycoprotein probes. Synthetic homogeneous monomeric glycoproteins proved to be useful substrates for kinetic analyses of the folding sensor enzyme UGGT. For a concise synthesis of a bismaleimide-linked dimer, we examined double native chemical ligation (dNCL) of a dimeric peptide-α-thioester. The dNCL to two equivalents of glycopeptides gave a homodimer. The dNCL to a 1 : 1 mixture of a glycopeptide and a non-glycosylated peptide gave all the three possible ligation products consisting of two homodimers and a heterodimer. Both the homodimer bearing two Man9GlcNAc2 (M9) oligosaccharides and the heterodimer bearing one M9 oligosaccharide were found to be good substrates of UGGT.
authors.affiliation: Department of Chemistry, Graduate School of Science, Osaka Univeristy, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan. mizumi@chem.sci.osaka-u.ac.jp kajihara@chem.sci.osaka-u.ac.jp.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Izumi
authors.forename: Shinji
authors.initials: S
authors.lastname: Komaki
authors.forename: Ryo
authors.initials: R
authors.lastname: Okamoto
authors.forename: Akira
authors.initials: A
authors.lastname: Seko
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Takeda
authors.forename: Yukishige
authors.initials: Y
authors.lastname: Ito
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kajihara
mesh_terms: D000595:Amino Acid Sequence; D060326:Chemistry Techniques, Synthetic; D004952:Esters / Q000737:chemistry*; D006020:Glycopeptides / Q000138:chemical synthesis* / Q000737:chemistry*; D007700:Kinetics; D008958:Models, Molecular; D017510:Protein Folding; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D013438:Sulfhydryl Compounds / Q000737:chemistry*
chemical_list: D004952:Esters; D006020:Glycopeptides; D013438:Sulfhydryl Compounds