J. Biochem, 1988, Vol. 103, No. 5 894-899
© 1988 Japanese Biochemical Society
research-article |
Carbohydrate Binding Specificity of a Beetle (Allomyrina dichotoma) Lectin1
Division of Chemical Toxicology and Immunochemistry, The University of Tokyo Bunkyo-ku, Tokyo 113
2To whom correspondence should be addressed.
Carbohydrate binding specificity of a lectin, allo A, isolated from a beetle (Allomyrina dichotoma), was investigated by means of lectin affinity chromatography. Sialylated complex-type and hybrid-type oligosaccharides/glycopeptides, and sialyllactose were retained by the column, whereas desialylated ones were retarded but not retained by the column. The association constants of allo A for biantennary oligosaccharides from human serum transferrin, determined by frontal analysis, were 8.0 × 105 M–1, 4.5 × 105 M–1, and 2.5 × 105 M–1 for disialo-, monosialo-, and asialo-oligosaccharides, respectively. Removal of the ß-galactose residues markedly reduced the association constant to 3.5 × 103 M–1 Furthermore, allo A was found to have no affinity for mucin-type glycopeptides carrying the sialylated Gal.ß1
3 Ga1NAc sugar sequence (Ka: 3.5 × 103 M–1). The results of this study indicated that allo A strongly binds to the trisaccharide structure, NeuAc
2–3(6)Gal, ß1–4G1cNAc, and that its binding potency is affected by the inner core structures of oligosaccharides and glycopeptides, because the presence of a bisecting N-acetyl-glucosamine residue and an a-fucose residue linked to the innermost N-acetylglucosamine residue reduced the association constants for oligosaccharides and glycopeptides.
1This work was supported by a Grant-in-Aid for Scientific Research (No. 61304063) from the Ministry of Education, Science and Culture of Japan. Portions of this paper (i.e. "EXPERIMENTAL PROCEDURES" and Figs. 1S-9S) are presented as a miniprint at the end of this paper.