N-Glycan Structures from the Major Glycoproteins of Pigeon Egg White

Abstract

N-Glycans from major glycoproteins of pigeon egg white (ovotransferrin, ovomucoid, and ovalbumins) were enzymatically released and were reductively aminated with 2-aminopyridine, separated, and structurally characterized by mass spectrometry and a three-dimensional mapping technique using three different columns of high performance liquid chromatography (HPLC) (Takahashi, N., Nakagawa, H., Fujikawa, K., Kawamura, Y., and Tomiya, N. (1995) Anal. Biochem. 226, 139 -146). Twentyfive major N-glycan structures, all of them hitherto unknown, were identified as pyridylamino derivatives. Of these, 13 were neutral, 10 were monosialyl, and 2 were disialyl oligosaccharides. All N-glycans contain from one to four Gal␣(1,4)Gal␤(1,4) sequences at the nonreducing terminal positions and are devoid of fucose residues. NAcetylneuraminic acids were ␣(2,6)-linked only to ␤-galactose. The HPLC profiles of the N-glycans from four different glycoproteins were qualitatively very similar to each other, but not identical in the peak distributions. Monosialyl glycans were most abundant in all four glycoproteins, followed by neutral glycans. Disialyl glycans were lowest in ovotransferrin, and highest in ovomucoid. Triantennary structures with bisecting GlcNAc were predominant in ovotransferrin, and tetra-antennary (with and without bisecting GlcNAc-containing) structures were predominant in other glycoproteins. Penta-antennary structures (with a sialic acid and without bisecting GlcNAc residue) were also found in small quantities in all four glycoproteins. In contrast to the chicken egg white counterparts, which contain mostly high mannose and hybrid types, all N-glycan structures in the major pigeon egg white glycoproteins are complex type.The presence of galabiose (Gal␣4Gal) sequence in N-glycans in any animal is only rarely noted. The only documented presence of such a sequence in N-glycan was that found in turtle dove ovomucoid (1, 2). The only other recorded presence of galabiose sequence were both in the O-glycosides found in the Chinese swiftlet nest (3) and in an insect cell line Mamestra brassicae clone SPCMb-92-C6 (4). As shown in the preceding paper (5), we have demonstrated that galabiose sequence is abundantly present in pigeon egg white (PEW) 1 glycoproteins, and it always occupies the terminal positions of the multiantennary structures. In the major N-glycans from the pigeon ovalbumin, no sialylation is found on the branch that contains the galabiose sequence. In contrast, chicken ovalbumin contained mostly high mannose type and hybrid types (6, 7) whereas chicken ovomucoid contains mostly galactose-less complex type (8). The preceding paper (5) also notes that, in contrast to the chicken and other avian egg whites hitherto investigated, the N-glycans in pigeon egg white glycoproteins seem to be more "mature," containing more of the multiantennary complex type structures. In view of these unique structural features, we felt that detailed structural studies were in order, not only to understand the underlying evolutionary sig...

Catch Bond-mediated Adhesion without a Shear Threshold

“…When P-fimbriated E. coli were allowed to accumulate on pigeon ovalbumin, a Gal-1,4-Gal-presenting glycoprotein (27,28), for 5 min at shears ranging from 0.01 to 4.3 pN/m 2 ( Fig. 7A), no shear threshold was seen, and accumulation decreased with increased shear.…”

Phylogenetic expression of Galα1-4Gal on avian glycoproteins: Glycan differentiation inscribed in the early history of modern birds

“…As expected, major proteins from all samples were visualized in the range of 30-80 kDa, although the mobility patterns varied from species to species. Different properties of avian egg white proteins, attributable to amino acid sequences and glycosylations in a species-specific manner, might have manifested in the Representative N-glycan structures of ovalbumins from chicken (36 -38) and pigeon (12,13). Specificity of lectins (Con A, RCA-I, and GS-I) and anti-P 1 mAb for the detection of oligosaccharides were also indicated.…”

“…We recently showed that pigeon (Rock Dove, Columba livia) express Gal␣1-4Gal (galabiose) antigens attached on glycoproteins from egg white (12,13) and serum (14), and analyzed their N-glycan structures (Fig. 1).…”

Warfare between Pathogens and Hosts: The Trickery of Sugars

“…A rather unexpected finding from the studies of pigeon ® E.coli E.coli α egg white N-glycans was that the NeuAc-Gal linkages in pigeon egg whites are α(2-6)-, which is the linkage found in humans, rather than α(2-3)-found in most other birds (8). Indeed, pigeons are found to be more resistant to avian influenza than other birds (41).…”

“…However, little is known about how the multivalency of such epitopes (i.e., clustering of glycan chains) will enhance the binding affinity. We fortuitously found that the pigeon egg white glycoproteins contain Neu5Acα(2-6)Gal linkage rather than Neu5Acα(2-3)Gal commonly found in other avian species (8). A subsequent report (9) showed that pigeons indeed are more resistant to avian flu.…”