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Complex N (complex + n)
Selected AbstractsGlycan side chains on naturally presented MHC class II ligandsJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 1 2005Jörn Dengjel Abstract The molecular characterization of unknown naturally presented major histocompatibility complex (MHC) class II glycopeptides carrying complex glycans has so far not been achieved, reflecting the different fragmentation characteristics of sugars and peptides in mass spectrometric analysis. Human leukocyte antigen (HLA)-DR-bound peptides were isolated by affinity purification, separated via high performance liquid chromatography and analyzed by matrix-assisted laser desorption/ionization and electrospray ionization mass spectrometry. We were able to identify two naturally processed MHC class II ligands, CD53122,136 and CD53121,136, carrying complex N -linked glycan side chains by a combination of in-source and collision-induced fragmentation on a quadrupole time-of-flight tandem mass spectrometer. Copyright © 2005 John Wiley & Sons, Ltd. [source] Production of a monoclonal antibody in plants with a humanized N -glycosylation patternPLANT BIOTECHNOLOGY JOURNAL, Issue 5 2007Matthias Schähs Summary In recent years, plants have become an attractive alternative for the production of recombinant proteins. However, their inability to perform authentic mammalian N -glycosylation may cause limitations for the production of therapeutics. A major concern is the presence of ,1,2-xylose and core ,1,3-fucose residues on complex N -linked glycans, as these N -glycan epitopes are immunogenic in mammals. In our attempts towards the humanization of plant N -glycans, we have generated an Arabidopsis thaliana knockout line that synthesizes complex N -glycans lacking immunogenic xylose and fucose epitopes. Here, we report the expression of a monoclonal antibody in these glycan-engineered plants that carry a homogeneous mammalian-like complex N -glycan pattern without ,1,2-xylose and core ,1,3-fucose. Plant and Chinese hamster ovary (CHO)-derived immunoglobulins (IgGs) exhibited no differences in electrophoretic mobility and enzyme-linked immunosorbent specificity assays. Our results demonstrate the feasibility of a knockout strategy for N -glycan engineering of plants towards mammalian-like structures, thus providing a significant improvement in the use of plants as an expression platform. [source] Identification of genes encoding N -glycan processing ,- N -acetylglucosaminidases in Trichoplusia ni and Bombyx mori: Implications for glycoengineering of baculovirus expression systemsBIOTECHNOLOGY PROGRESS, Issue 1 2010Christoph Geisler Abstract Glycoproteins produced by non-engineered insects or insect cell lines characteristically bear truncated, paucimannose N -glycans in place of the complex N -glycans produced by mammalian cells. A key reason for this difference is the presence of a highly specific N -glycan processing ,- N -acetylglucosaminidase in insect, but not in mammalian systems. Thus, reducing or abolishing this enzyme could enhance the ability of glycoengineered insects or insect cell lines to produce complex N -glycans. Of the three insect species routinely used for recombinant glycoprotein production, the processing ,- N -acetylglucosaminidase gene has been isolated only from Spodoptera frugiperda. Thus, the purpose of this study was to isolate and characterize the genes encoding this important processing enzyme from the other two species, Bombyx mori and Trichoplusia ni. Bioinformatic analyses of putative processing ,- N -acetylglucosaminidase genes isolated from these two species indicated that each encoded a product that was, indeed, more similar to processing ,- N -acetylglucosaminidases than degradative or chitinolytic ,- N -acetylglucosaminidases. In addition, over-expression of each of these genes induced an enzyme activity with the substrate specificity characteristic of processing, but not degradative or chitinolytic enzymes. Together, these results demonstrated that the processing ,- N -acetylglucosaminidase genes had been successfully isolated from Trichoplusia ni and Bombyx mori. The identification of these genes has the potential to facilitate further glycoengineering of baculovirus-insect cell expression systems for the production of glycosylated proteins. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source] Arthrobacter Endo-,- N -Acetylglucosaminidase Shows Transglycosylation Activity on Complex-Type N -Glycan Oxazolines: One-Pot Conversion of Ribonuclease B to Sialylated Ribonuclease CCHEMBIOCHEM, Issue 10 2010Wei Huang Dr. Transforming protein glycosylation: The Arthrobacter endo-,- N -acetylglucosaminidase (Endo-A) was found to transglycosylate complex N -glycan oxazolines without product hydrolysis. Given its high activity in hydrolyzing high-mannose-type N -glycans, the newly discovered property enables a one-pot switch of glycans in a glycoprotein, as shown by the conversion of heterogeneous RNase B to homogeneous sialylated RNase C. [source] Monomeric Cu(II) Complex Containing Chiral Phase-transfer Catalyst as Ligand and Its Asymmetrically Catalytic ReactionCHINESE JOURNAL OF CHEMISTRY, Issue 2 2008Zhi-Rong QU Abstract The thermal treatment of CuCl2 with N -(4,-vinylbenzyl)cinchonidinium chloride (L1) afforded a monomeric discrete homochiral copper(II) complex N -4,-(vinylbenzyl)cinchonidinium trichlorocoprate(II) (1). Their applications to the enantioselectively catalytic alkylation reaction of N -(diphenylmethylidene)glycine tert -butyl ester (3) show that the higher ee value observed in catalyst 1 than that in the corresponding free ligand L1 is probably due to the rigidity enhancement after the coordination of N atom of quinoline ring to the copper ion. [source] | |||||||||||||