Templating carbohydrate-functionalised polymer-scaffolded dynamic combinatorial libraries with lectins†
A conceptually new approach to the design of macromolecular receptors for lectins is outlined. Carbohydrate-functionalised Polymer-Scaffolded Dynamic Combinatorial Libraries (PS-DCLs) have been prepared in aqueous solution by the reversible conjugation of carbohydrates possessing acylhydrazide functionalities in their aglycone on to an aldehyde-functionalised polymer scaffold. PS-DCLs have been shown to undergo compositional change in response to the addition of lectin templates, with polymer scaffolds preferentially incorporating carbohydrate units which recognise the lectin added. This compositional change has been shown to generate polymers of significantly enhanced affinity for the lectin added, with enhancements in free energy of binding in the range of 5.2–8.8 kJ mol−1 observed. Experiments indicate that these enhancements are not only as a consequence of increased display of the preferred carbohydrate upon the polymer scaffold, but that templation also reorganises key residues into strategic positions in order to interact more strongly with the target.