HPLC‐ESI‐MS and MS/MS structural characterization of multifucosylated N‐glycoforms of the basic proline‐rich protein IB‐8a CON1+ in human saliva

摘要: This study describes the characterization of glycan moieties and peptide backbone six glycoforms IB-8a CON1(+), a basic proline-rich protein present in human saliva. MS analyses on intact glycoproteins before after N-deglycosylation with PNGase F high-resolution MS/MS sequencing by LTQ Orbitrap XL peptides glycopeptides from tryptic digests allowed structural polypeptide backbone, as well to establish glycosylation site at asparagine residue 98th position. Five carry biantennary N-linked fucosylated innermost N-acetylglucosamine core showing zero four additional fucoses antennal region. The sixth glycoform carries monoantennary monofucosylated oligosaccharide. cluster was detected 28 71 adult saliva specimens. Level fucosylation showed interindividual variability major relative abundance for trifucosylated glycoform. Nonglycosylated CON1(+) variant CON1(-), lacking site, have been also