Structural features of N-glycans linked to royal jelly glycoproteins: structures of high-mannose type, hybrid type, and biantennary type glycans.
The structures of N-glycans of total glycoproteins in royal jelly have been explored to clarify whether antigenic N-glycans occur in the famous health food. The structural feature of N-glycans linked to glycoproteins in royal jelly was first characterized by immunoblotting with an antiserum against plant complex type N-glycan and lectin-blotting with Con A and WGA. For the detail structural analysis of such N-glycans, the pyridylaminated (PA-) N-glycans were prepared from hydrazinolysates of total glycoproteins in royal jelly and each PA-sugar chain was purified by reverse-phase HPLC and size-fractionation HPLC. Each structure of the PA-sugar chains purified was identified by the combination of two-dimensional PA-sugar chain mapping, ESI-MS and MS/MS analyses, sequential exoglycosidase digestions, and 500 MHz 1H-NMR spectrometry. The immunoblotting and lectinblotting analyses preliminarily suggested the absence of antigenic N-glycan bearing beta1-2 xylosyl and/or alpha1-3 fucosyl residue(s) and occurrence of beta1-4GlcNAc residue in the insect glycoproteins. The detailed structural analysis of N-glycans of total royal jelly glycoproteins revealed that the antigenic N-glycans do not occur but the typical high mannose-type structure (Man(9 to approximately 4)GlcNAc2) occupies 71.6% of total N-glycan, biantennary-type structures (GlcNAc2Man3 GlcNAc2) 8.4%, and hybrid type structure (GlcNAc1 Man4GlcNAc2) 3.0%. Although the complete structures of the remaining 17% N-glycans; C4, (HexNAc3 Hex3HexNAc2: 3.0%), D2 (HexNAc2Hex5HexNAc2: 4.5%), and D3 (HexNAc3Hex4HexNAc2: 9.5%) are still obscure so far, ESI-MS analysis, exoglycosidase digestions by two kinds of beta-N-acetylglucosaminidase, and WGA blotting suggested that these N-glycans might bear a beta1-4 linkage N-acetylglucosaminyl residue.
Kimura
Y
Y
Department of Bioresources Chemistry, Faculty of Agriculture, Okayama University, Japan. yosh8mar@cc.okayama-u.ac.jp
Miyagi
C
C
Kimura
M
M
Nitoda
T
T
Kawai
N
N
Sugimoto
H
H
D015153:Blotting, Western; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002851:Chromatography, High Pressure Liquid; D005227:Fatty Acids / Q000737:chemistry*; D006023:Glycoproteins / Q000737:chemistry*; D008358:Mannose / Q000737:chemistry*; D008969:Molecular Sequence Data; D011134:Polysaccharides / Q000737:chemistry* / Q000302:isolation & purification; D000099219:Royal Jelly
D005227:Fatty Acids; D006023:Glycoproteins; D008358:Mannose; D011134:Polysaccharides; D000099219:Royal Jelly