N-glycan structures of pigeon IgG: a major serum glycoprotein containing Galalpha1-4 Gal termini..
We had shown previously that all major glycoproteins of pigeon egg white contain Galalpha1-4Gal epitopes (Suzuki, N., Khoo, K. H., Chen, H. C., Johnson, J. R., and Lee, Y. C. (2001) J. Biol. Chem. 276, 23221-23229). We now report that Galalpha1-4Gal-bearing glycoproteins are also present in pigeon serum, lymphocytes, and liver, as probed by Western blot with Griffonia simplicifolia-I lectin (specific for terminal alpha-Gal) and anti-P1 (specific for Galalpha1-4Galbeta1-4GlcNAcbeta1-) monoclonal antibody. One of the major glycoproteins from pigeon plasma was identified as IgG (also known as IgY), which has Galalpha1-4Gal in its heavy chains. High pressure liquid chromatography, mass spectrometric (MS), and MS/MS analyses revealed that N-glycans of pigeon serum IgG included (i) high mannose-type (33.3%), (ii) disialylated biantennary complex-type (19.2%), and (iii) alpha-galactosylated complex-type N-glycans (47.5%). Bi- and tri-antennary oligosaccharides with bisecting GlcNAc and alpha1-6 Fuc on the Asn-linked GlcNAc were abundant among N-glycans possessing terminal Galalpha1-4Gal sequences. Moreover, MS/MS analysis identified Galalpha1-4Galbeta1-4Galbeta1-4GlcNAc branch terminals, which are not found in pigeon egg white glycoproteins. An additional interesting aspect is that about two-thirds of high mannose-type N-glycans from pigeon IgG were monoglucosylated. Comparison of the N-glycan structures with chicken and quail IgG indicated that the presence of high mannose-type oligosaccharides may be a characteristic of these avian IgG.
Suzuki
Noriko
N
Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA.
Khoo
Kay-Hooi
KH
Chen
Chin-Mei
CM
Chen
Hao-Chia
HC
Lee
Yuan C
YC
D000818:Animals; D015153:Blotting, Western; D010856:Columbidae / Q000276:immunology*; D004187:Disaccharides; D007074:Immunoglobulin G / Q000097:blood / Q000737:chemistry*; D007143:Immunoglobulin Heavy Chains / Q000737:chemistry; D008099:Liver / Q000737:chemistry / Q000276:immunology; D008214:Lymphocytes / Q000737:chemistry / Q000276:immunology; D008358:Mannose / Q000032:analysis; D011134:Polysaccharides / Q000032:analysis / Q000097:blood / Q000737:chemistry*
D004187:Disaccharides; D007074:Immunoglobulin G; D007143:Immunoglobulin Heavy Chains; D011134:Polysaccharides; C032103:4-O-alpha-D-galactopyranosyl-D-galactose; D008358:Mannose