Biorecognition of sugar containing N-(2-hydroxypropyl)methacrylamide copolymers by immobilized lectin

The interactions of sugar containing N-(2-hydroxypropyl)methacrylamide (HPMA) copolymers with Tetragonolobus purpureas (Lotus tetragonolobus) lectin immobilized on 4% beaded agarose have been studied. HPMA copolymers containing side-chains terminating in N-acylated amino sugars, namely, fucosylamine, galactosamine, glucosamine and mannosamine were synthesized and their biorecognition evaluated. As expected, only fucosylamine containing HPMA copolymers showed specific binding to the lectin. The dissociation constants (K-d) for HPMA copolymers were determined by frontal affinity chromatography. The binding constant was dependent on the amount of fucosylamine residues per macromolecule. An increase in fucosylamine content from 9,9 to 33,2 mol-% resulted in a decrease of K-d by one order of magnitude. Incorporation of hydrophobic side-chains such as glycylglycyl-5-[4-(2-aminoethylcarbamoyl)phenylazo]salicylic acid, 1'-(beta-hydroxyethyl)-3',3'-dimethyl-6-nitrospiro(2H-1-benzopyran-2,2'-indoline) (SP), or 1'-(beta-glycylglycyloxyethyl)-3',3'-dimethyl-6-nitrospiro(2H-1-benzopyran-2,2'-indoline) (GG-SP) into the copolymers increased the non-specific binding to the lectin. Photoinduced isomerization of bound spiropyrans to merocyanines was accompanied by changes in the conformation and biorecognition of HPMA copolymers. The results obtained demonstrated the impact of the structure and solution conformation of sugar containing HPMA copolymers on their biorecognition.