Occurrence of free sialyl oligosaccharides related to N-glycans (sialyl free N-glycans) in animal sera.
Free oligosaccharides that are structurally related to N-glycans [free N-glycans (FNGs)] are widely distributed in the cytosol of animal cells. The diverse molecular mechanisms responsible for the formation of these FNGs have been well clarified. In this study we demonstrate the wide occurrence of sialylated FNGs in sera of various animals. The features of these extracellular FNGs are quite distinct from the cytosolic FNGs, as they are Gn2-type glycans, bearing an N,N'-diacetylchitobiose unit at their reducing termini, while the cytosolic FNGs are predominantly Gn1-type, with a single GlcNAc at their reducing termini. The major structures observed varied from species to species, and the structures of the FNGs appear to be correlated with the major sialyl N-glycans on serum glycoproteins, suggesting that the serum FNGs are produced by hepatocytes. Interestingly, glycan-profiles of the FNGs indicated that they are altered in a developmental stage-dependent manner. Sialyl FNGs in the sera may not only be of biological relevance, in that they might reflect the functionality of the liver, but also can be attractive sources for obtaining uniform sialyl FNGs in the chemoenzymatic synthesis of glycoproteins.
Glycometabolome Team, RIKEN-Max Planck Institute Joint Research Center, RIKEN Global Research Cluster, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
Junichi
J
Seino
Glycometabolome Team, RIKEN-Max Planck Institute Joint Research Center, RIKEN Global Research Cluster, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
Haruhiko
H
Fujihira
Division of Functional Glycomics, Life Science Research Center, Institute of Research Promotion, Kagawa University, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0793, Japan.
Shin-Ichi
SI
Nakakita
Glycometabolome Team, RIKEN-Max Planck Institute Joint Research Center, RIKEN Global Research Cluster, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
Yuki
Y
Masahara-Negishi
Department of Molecular Biochemistry and Clinical Investigation, Osaka University School of Medicine, 1-7 Yamada-oka, Suita, Osaka 565-0871, Japan.
Eiji
E
Miyoshi
Division of Functional Glycomics, Life Science Research Center, Institute of Research Promotion, Kagawa University, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0793, Japan.
Jun
J
Hirabayashi
Glycometabolome Team, RIKEN-Max Planck Institute Joint Research Center, RIKEN Global Research Cluster, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan tsuzuki_gm@riken.jp.
Tadashi
T
Suzuki
D000818:Animals; D002645:Chickens / Q000097:blood; D003600:Cytosol / Q000737:chemistry; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D011134:Polysaccharides / Q000097:blood* / Q000737:chemistry; D011817:Rabbits; D051381:Rats; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013552:Swine / Q000097:blood
D011134:Polysaccharides
HPLC; asialoglycoprotein receptor; serum; sialyl free N-glycan