PMID: 7525874

 

    Legend: Sugar

Title : Carbohydrate structures of beta-trace protein from human cerebrospinal fluid: evidence for "brain-type" N-glycosylation

Abstract :
  1. The carbohydrate structures of beta-trace protein from human cerebrospinal fluid have been elucidated
  2. This protein carries exclusively N-linked oligosaccharides at two sites ( Asn29 and Asn56 )
  3. Enzymatically released N-glycans were studied by com position al and methylation analyses, high-pH anion-exchange chromatography, and liquid secondary ion mass spectrometry
  4. All glycans were found to be of the complex type , and most (90%) of them were biantennary with no (40%), one (40%), or two (20%) N-acetylneuraminic acid residues
  5. The rest were triantennary chains or biantennary chains with intact or truncated lactosamine repeats.
  6. The innermost N-acetylglucosamine residues of nearly all structures were found to be alpha 1,6-fucosylated
  7. Peripheral fucose (about 20% alpha 1,3-linked to N-acetylglucosamine) was also detected
  8. Seventy percent of the oligosaccharides contained a bisecting N-acetylglucosamine.
  9. Especially in the neutral, but also in the monosialylated oligosaccharide fractions, many incomplete antennae consisting of N-acetylglucosamine only were present
  10. At least 20 different N-glycans were identified
  11. Analysis of the site-specific glycosylation patterns at Asn29 and Asn56 revealed only minor differences
  12. According to the structural features (a high degree of fucosylation , high amounts of bisecting N-acetylglucosamine, as well as terminal N-acetylglucosamine and galactose residues , and significant amounts of N-acetylneuraminic acid in alpha 2,3 linkage), this protein can be classified as "brain-type" glycosylated