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 all defined and organzied. In this study, the recognition factors involved in these inteactions were azalyzed by our well developed method- the enzyme linked lectinosorbent (ELLSA) and inhibition assay. Based on all data obtained, it is concluded that Con A, as previous report, has a relatively broad and wide recognition ability with the Manα1→ and Glcα1→ related glycans. In addition to it reacted strongly with yeast mannan and glycogens, it 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), thyroglobin and lactosferrin. The recognition specificity of Con A towards ligands, expressed by Molar Relative Potency (Molar R.P.), in a decreasing order is as follows: a1→3, a1→6 Mannopentaose (M5) and Biantennary N-linked core pentasaccharide (MDi) ≥ a1→3, a1→6 Mannotriose (M3) > Mana1→3Man (α1→3Mannobiose), Mana1→2Man (α1→2Mannobiose), Mana1→6Man (α1→6Mannobiose), Mana1→4Man (α1→4Mannobiose) > GlcNAcb1→2Man (b1→2 N-Acetyl glucosamine-mannose) > Mana1→/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 GlcNAcb1→ branches (M3 to M9 / MMono to Penta etc.) and a table of three Mana1→ and Glca1→ 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.

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

“…The glycan codes for Gal/GalNAc speci c lectin-glycan interactions has been de ned since early 1990 [7,31]. It is one of the best and easy ways to elucidate the structures and functional roles of Gal/GalNAc related glycan complexes.…”

“…The Factors involved in the recognition process of the lectin-glycan interactions are de ned as Recognition Factors (RFs) [31]. During the past 70 years, six of them have been selected and applied to demonstrate the mammalian Gal/GalNAc related glycoconjugate-glycan interactions [7,31,35,60]. They are: (i) Sub-monosaccharide speci city: anomers and epimers in the pyranose form of monosaccharides;…”

“…Although RFs of the most (ii)-(iv) [i.e RF-2 to RF-5] are the weak ones, while they are the essential and core elements in the recognition process, which are similar to amino acids peptide sequence in a protein. They have also been used to classify the applied lectins [7,31,35]. As the intensities and avidities of the polyvalency of the Gal/GalNAc related glycotopes and their resulting conformational features [RF-(vi)] has been found to be the critical factor for the most mechanism of lectin-glycan interactions.…”

“…As the intensities and avidities of the polyvalency of the Gal/GalNAc related glycotopes and their resulting conformational features [RF-(vi)] has been found to be the critical factor for the most mechanism of lectin-glycan interactions. Their intensities can be increased 1.0×10 6 times more than their monomeric status [31,35]. Therefore, the RF-(vi), in the Gal/GalNAc system was coined as super recognition factor for the mechanism of lectin-glycan interactions.…”