N-Acetyllactosamine (LacNAc; Galβ4GlcNAc) is a typical disaccharide ligand of galectins. The most abundant members of these human lectins, galectin-1 (Gal-1) and galectin-3 (Gal-3), participate in a number of pathologies including cancerogenesis and metastatic formation. In this study, we synthesized a series of fifteen N-(2-hydroxypropyl)methacrylamide (HPMA)-based glycopolymers with varying LacNAc amounts and presentations and evaluated the impact of their architecture on the binding affinity to Gal-1 and Gal-3. The controlled radical reversible addition-fragmentation chain transfer copolymerization technique afforded linear polymer precursors with comparable molecular weight (Mn ≈ 22,000 g mol-1) and narrow dispersity (D̵ ≈ 1.1). The precursors were conjugated with the functionalized LacNAc disaccharide (4-22 mol % content in glycopolymer) prepared by enzymatic synthesis under catalysis by β-galactosidase from Bacillus circulans. The structure-affinity relationship study based on the enzyme-linked immunosorbent assay revealed that the type of LacNAc presentation, individual or clustered on bi- or trivalent linkers, brings a clear discrimination (almost 300-fold) between Gal-1 and Gal-3, reaching avidity to Gal-1 in the nanomolar range. Whereas Gal-1 strongly preferred a dense presentation of individually distributed LacNAc epitopes, Gal-3 preferred a clustered LacNAc presentation. Such a strong galectin preference based just on the structure of a multivalent glycopolymer type is exceptional. The prepared nontoxic, nonimmunogenic, and biocompatible glycopolymers are prospective for therapeutic applications requiring selectivity for one particular galectin.

Department of Health Care Disciplines and Population Protection Faculty of Biomedical Engineering Czech Technical University Prague Sítná sq 3105 CZ 272 01 Kladno Czech Republic

Institute of Biotechnology and Helmholtz Institute for Biomedical Engineering RWTH Aachen Pauwelstr 20 D 52079 Aachen Germany

Institute of Macromolecular Chemistry Czech Academy of Sciences Heyrovského náměstí 2 CZ 162 06 Prague 6 Czech Republic

Institute of Microbiology Czech Academy of Sciences Vídeňská 1083 CZ 142 20 Prague 4 Czech Republic

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