N-glycosylation at Asn(491) in the Asn-Xaa-Cys motif of human transferrin.
Glycopeptides derived from human transferrin were exhaustively analyzed by matrix-assisted laser desorption ionization and electrospray ionization mass spectrometry (MS). Both MS techniques clearly revealed the sequences of and the attachment sites of bi-antennary complex-type oligosaccharides, at both Asn432 and Asn630, both of which are located in a well-known motif for N-glycosylation, Asn-Xaa-Ser/Thr, but also at Asn491 in the Asn-Xaa-Cys motif. The latter has been reported to be a minor N-glycosylation site in several glycoproteins. The relative abundance of this abnormal glycosylation was estimated to be approximately 2 mol% of the transferrin preparation used in this study.
Satomi
Yoshinori
Y
Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan.
Shimonishi
Yasutsugu
Y
Takao
Toshifumi
T
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001216:Asparagine / Q000737:chemistry*; D006020:Glycopeptides / Q000032:analysis / Q000378:metabolism; D006031:Glycosylation; D006801:Humans; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000032:analysis / Q000378:metabolism; D021241:Spectrometry, Mass, Electrospray Ionization; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014168:Transferrin / Q000737:chemistry*
D006020:Glycopeptides; D010446:Peptide Fragments; D014168:Transferrin; D001216:Asparagine