Roles of the structural units, glycotopes / mammalian N-glycans for Con A-glycan interactions, their codes, and their recognition factors.

Abstract

The binding property of Con A has been studied intensively and applied widely to glycoconjugates / glycobiology for over 80 years. However, its role and functional relationship of Con A with these mammalian structural units, glycotopes, N-glycan chains, as well as their polyvalent forms in N-glycoproteins involved in the Con A-glycan interactions have not been well defined and organized. In this study, the recognition factors involved in these interactions were analyzed by our well developed method- the enzyme linked lectinosorbent (ELLSA) and inhibition assay. Based on all the data obtained, it is concluded that Con A, as previously reported, has a relatively broad and wide recognition ability of the Manα1 → and Glcα1 → related glycans. It reacted not only strongly with yeast mannan and glycogens, but also bound well with a large number of mammalian N-glycans, including the N-glycans of rat sublingual gp (RSL), human Tamm-Horsfall glycoprotein (THGP), thyroglobulin and lactoferrin. The recognition specificity of Con A towards ligands, expressed by Molar Relative Potency (Molar R.P.), in a decreasing order is as follows: α1 → 3, α1 → 6 Mannopentaose (M₅) and Biantennary N-linked core pentasaccharide (M_Di) ≥ α1 → 3, α1 → 6 Mannotriose (M₃) > Manα1 → 3Man (α1 → 3Mannobiose), Manα1 → 2Man (α1 → 2Mannobiose), Manα1 → 6Man (α1 → 6Mannobiose), Manα1 → 4Man (α1 → 4Mannobiose) > GlcNAcβ1 → 2Man (β1 → 2 N-Acetyl glucosamine-mannose) > Manα1 → /Glcα1 → > Man > Glc, while Gal / GalNAc were inactive. Furthermore, the Man related code system, in this study, is proposed to express by both numbers of Man and GlcNAcβ1 → branches (M₃ to M₉ / M_{Mono to Penta etc.}) and a table of three Manα1 → and Glcα1 → related biomasses of six recognition factors involved in the Con A-glycan interactions has also been demonstrated. These themes should be one of the most valuable advances since 1980s.