title: Density variant glycan microarray for evaluating cross-linking of mucin-like glycoconjugates by lectins.
abstract: Interactions of mucin glycoproteins with cognate receptors are dictated by the structures and spatial organization of glycans that decorate the mucin polypeptide backbone. The glycan-binding proteins, or lectins, that interact with mucins are often oligomeric receptors with multiple ligand binding domains. In this work, we employed a microarray platform comprising synthetic glycopolymers that emulate natural mucins arrayed at different surface densities to evaluate how glycan valency and spatial separation affect the preferential binding mode of a particular lectin. We evaluated a panel of four lectins (Soybean agglutinin (SBA), Wisteria floribunda lectin (WFL), Vicia villosa-B-4 agglutinin (VVA), and Helix pomatia agglutin (HPA)) with specificity for α-N-acetylgalactosamine (α-GalNAc), an epitope displayed on mucins overexpressed in many adenocarcinomas. While these lectins possess the ability to agglutinate A(1)-blood cells carrying the α-GalNAc epitope and cross-link low valency glycoconjugates, only SBA showed a tendency to form intermolecular cross-links among the arrayed polyvalent mucin mimetics. These results suggest that glycopolymer microarrays can reveal discrete higher-order binding preferences beyond the recognition of individual glycan epitopes. Our findings indicate that glycan valency can set thresholds for cross-linking by lectins. More broadly, well-defined synthetic glycopolymers enable the integration of glycoconjugate structural and spatial diversity in a single microarray screening platform.
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720, United States.
authors.forename: Kamil
authors.initials: K
authors.lastname: Godula
authors.forename: Carolyn R
authors.initials: CR
authors.lastname: Bertozzi
mesh_terms: D005456:Fluorescent Dyes; D006001:Glycoconjugates / Q000737:chemistry*; D037102:Lectins / Q000737:chemistry*; D018716:Molecular Mimicry; D009077:Mucins / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry*
chemical_list: D005456:Fluorescent Dyes; D006001:Glycoconjugates; D037102:Lectins; D009077:Mucins; D011134:Polysaccharides