High prevalence of 2-mono- and 2,6-di-substituted manol-terminating sequences among O-glycans released from brain glycopeptides by reductive alkaline hydrolysis.
Di- to heptasaccharides isolated from total nondialyzable brain glycopeptides after release by alkaline borohydride treatment have been subjected to mass spectrometric and nuclear magnetic resonance spectroscopic analyses supplemented by TLC-MS analyses of derived neoglycolipids. A family of Manol-terminating oligosaccharides has been revealed which includes novel sequences with a 2, 6-disubstituted Manol: In contrast to the Manol-terminating HNK-1 antigen-positive chains described previously that occur as a minor population [Yuen, C.-T., Chai, W., Loveless, R.W., Lawson, A.M., Margolis, R.U. & Feizi, T. (1997) J. Biol. Chem. 272, 8924-8931], the above oligosaccharides are abundant. The ratio of these compounds to the classical N-acetylgalactosaminitol-terminating oligosaccharides is about 1 : 3. Thus, there appears to be in higher eukaryotes a major alternative pathway related to the yeast-type protein O-mannosylation, the enzymatic basis and functional importance of which now require investigation.
Chai
W
W
The Glycosciences Laboratory, Imperial College School of Medicine, Northwick Park Hospital, Harrow, Middlesex, UK.
Yuen
C T
CT
Kogelberg
H
H
Carruthers
R A
RA
Margolis
R U
RU
Feizi
T
T
Lawson
A M
AM
D000818:Animals; D001923:Brain Chemistry; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002852:Chromatography, Ion Exchange; D002855:Chromatography, Thin Layer; D006020:Glycopeptides / Q000737:chemistry* / Q000302:isolation & purification; D007202:Indicators and Reagents; D008353:Mannitol / Q000032:analysis*; D013058:Mass Spectrometry; D008745:Methylation; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry* / Q000302:isolation & purification; D011817:Rabbits
D006020:Glycopeptides; D007202:Indicators and Reagents; D009844:Oligosaccharides; D008353:Mannitol