First evidence for occurrence of Galbeta1-3GlcNAcbeta1-4Man unit in N-glycans of insect glycoprotein: beta1-3Gal and beta1-4GlcNAc transferases are involved in N-glycan processing of royal jelly glycoproteins.
On a way of structural analysis of total N-glycans linked to glycoproteins in royal jelly (Kimura, Y. et al., Biosci. Biotechnol. Biochem., 64, 2109-2120 (2000), Kimura, M. et al., Biosci. Biotechnol. Biochem., 66, 1985-1989 (2002)), we found that some complex type N-glycans containing a beta1-3galactose residue occur on the insect glycoproteins. Up to date, it has been considered that naturally occurring insect glycoproteins do not bear the galactose-containing N-glycans, therefore, in this report we describe the structural analysis of the complex type N-glycans of royal jelly glycoproteins. By a combination of endo- and exo-glycosidase digestions, IS-MS analysis, and 1H-NMR spectroscopy, the structures of the beta1-3 galactose-containing N-glycan were identified as the following; GlcNAcbeta1-2Manalpha1-6[GlcNAcbeta1-2(Galbeta1-3GlcNAcbeta1-4)Manalpha1-3]Manbeta1-4GlcNAcbeta1-4GlcNAc, Manalpha1-3Manalpha1-6[GlcNAcbeta1-2(Galbeta1-3GlcNAcbeta1-4)Manalpha1-3]Manbeta1-4GlcNAcbeta1-4GlcNAc, and Manalpha1-6(Manalpha1-3)Manalpha1-6[GlcNAcbeta1-2(Galbeta1-3GlcNAcbeta1-4)Manalpha1-3]Manbeta1-4GlcNAcbeta1-4GlcNAc. To our knowledge, this is the first report showing that the Galbeta1-3GlcNAcbeta1-4Man unit occurs in N-glycans of insect glycoproteins, indicating a beta1-3 galactosyl transferase and beta1-4GlcNAc transferase (GNT-IV) are expressed in the honeybee cells.
Kimura
Yoshinobu
Y
Department of Bioresources Chemistry, Faculty of Agriculture, Okayama University, Tsushima-Naka 1-1-1, Okayama 700-8530, Japan. yosh8mar@cc.okayama-u.ac.jp
Tsumura
Kazunori
K
Kimura
Mariko
M
Okihara
Kiyoshi
K
Sugimoto
Hiroyuki
H
Yamada
Hideo
H
D000818:Animals; D001516:Bees / Q000737:chemistry / Q000201:enzymology; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism*; D005690:Galactose / Q000031:analogs & derivatives*; D005700:Galactosyltransferases / Q000378:metabolism*; D005964:Glucosyltransferases / Q000378:metabolism*; D006023:Glycoproteins / Q000737:chemistry* / Q000378:metabolism; D019476:Insect Proteins / Q000737:chemistry* / Q000378:metabolism; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D011134:Polysaccharides / Q000737:chemistry* / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization; D000099219:Royal Jelly
D005227:Fatty Acids; D005690:Galactose; D005700:Galactosyltransferases; D005964:Glucosyltransferases; D006023:Glycoproteins; D019476:Insect Proteins; D011134:Polysaccharides; D000099219:Royal Jelly