PMID: 7514386

 

    Legend: Sugar

Title : Structural study on the glycosyl-phosphatidylinositol anchor and the asparagine-linked sugar chain asparagine-linked sugar chain of a soluble form of CD59 in human urine

Abstract :
  1. CD59 is an 18-kDa glycoprotein widely expressed on human cells
  2. An important structural feature of CD59 is its attachment to the cell surface via a glycosyl-phosphatidylinositol ( GPI ) anchor
  3. CD59 , like many GPI-anchored proteins , has been found in urine, serum, and other body fluids
  4. The structures of the GPI anchor and the asparagine-linked sugar chain asparagine-linked sugar chain of a soluble form of CD59 in urine, U- CD59 , were determined
  5. Purified U- CD59 released 1 mol of inositol per mole of protein by nitrous acid deamination, which cleaved between glucosamine and inositol present commonly in the GPI anchor
  6. This indicates that a GPI anchor, which ended with inositol, is linked at the carboxy terminus of U- CD59
  7. The peptide containing an asparagine-linked sugar chain and the peptide containing a glycan portion asparagine-linked sugar chain and the peptide containing a glycan portion of the GPI anchor were isolated after trypsin digestion of U- CD59
  8. The asparagine-linked sugar chains and the glycan portion asparagine-linked sugar chains and the glycan portion of the GPI anchor were isolated from these peptides following hydrazinolysis or deamination and dephosphorylation, respectively
  9. Their structures were analyzed by sequential exoglycosidase digestion and methylation analyses
  10. The structures of the asparagine-linked sugar chains asparagine-linked sugar chains of U- CD59 were biantennary complex type , only 4.2% of which are monosialylated
  11. The backbone structure of the GPI anchor was similar to that of Try-panosoma brucei variant surface glycoprotein , but showed significant variations in its side- chain moieties
  12. This is the first detailed structural analysis of the human GPI anchor and the first detailed analysis of the carboxyl-terminal structure of the soluble-form GPI-anchored protein
  13. The results indicate that the backbone structure of the GPI anchor is conserved from parasites to human and that at least a part of the soluble-form GPI-anchored protein has the structure produced by the action of glycan-phosphatidylinositol-specific phospholipase D