N-glycans

HEMPAS (MIM 224100) Abnormalities in certain enzymes (eg, mannosidase II and others) involved in the biosynthesis of N-glycans, particularly affecting the red blood cell membrane. 

Hereditary erythroblastic multinuclearity witha positive acidified serum lysis test (congenital dyserythropoietic anemia type II). This is a relatively mild form of anemia. It reflects at least in part the presence in the red cell membranes of various glycoproteins with abnormal N-glycan chains, which contribute to the susceptibility to lysis. 

Type II disorders are due to mutations in genes encoding enzymes (eg, GIcNAc transferase-2, causing CDG lla) involved in the processing of N-glycan chains... 

Matsuda, K., Takahashi, N., Tsukamoto, Y., Honma, H., and Kohri, K., N-glycan structures of osteopontin from human bone, Biochem. Biophys. Res. Commun., 268, 814, 2000. 

Reason, A.J., Ellis, L.A., Appleton, J.A., Wisnewski, N., Grieve, R.B., McNeil, M., Wassom, D.L., Morris, H.R. and Dell, A. (1994) Novel tyvelose-containing tri- and tetra-antennary N-glycans in the immunodominant antigens of the intracellular parasite TrichineUa spiralis. Glycobiology 4, 593-603. 

Leteux, C., Childs, R.A., Chai, W., Stoll, M.S., Kogelberg, H., and Feizi, T. (1998) Biotinyl-L-3-(2-naph-thyl)-alanine hydrazide derivatives of N-glycans Versatile solid-phase probes for carbohydrate-recognition studies. Glycobiology 8, 227-236. 

Srikrishna, G., Toomre, D.K., Manzi, A., Panneerselvam, K., Freeze, H.H., Varki, A., and Varki, N.M. (2001) A novel anionic modification of N-glycans on mammalian endothelial cells is recognized by activated neutrophils and modulates acute inflammatory responses./. Immunol. 166, 624-632. 

Fig. 1.6 Structure of N-glycans isolated from (a) alfalfa-derived C5-1 and (b) murine C5-1.

Alfalfa, clover High yield, useful for animal vaccines, clonal propagation, homogenous N-glycans (alfalfa) Low protein stability in harvested material, presence of oxalic acid... 

Fig. 15.3 Plant and mammalian N-glycans have different structures. As illustrated here, a core structure (in gray) is common to plant and mammalian biantennary complex N-glycans. However, differences in the glycan processing machineries in plants and in mammals result in the absence of sialic acids in the terminal position of the antennae and the presence of a bisecting p (1,2) -xylose and of an a(l,3)-fucose residue in PMPs instead of the a(l,6)-fucose linked to the proximal N-acetylglucos-amine of native mammalian N-glycans.

Plant-made Pharmaceuticals Possess Immunogenic N-glycans 241... 

Plants are not the only heterogeneous expression system to produce potentially immunogenic N-glycans. When antibodies are produced in non-human mammalian... 

Current Strategies to Eliminate Immunogenic N-glycans from Plant-made Pharmaceuticals... 

Fig. 15.6 Glycosylation of antibodies produced with ER retention signals in tobacco plants. Antibodies fused with two (left panel) or four (middle panel) KDEL-ER retention signals are respectively or exclusively glycosylated with high mannose type, and probably non-immuno-genic, N-glycans.

Towards Humanized N-glycans on PMPs Through the Expression of Mammalian Glyco-syltransferases in the Plant Golgi Apparatus... 

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