Crosslinked Network with Rotatable Binding Sites Based on Monocarboxylated α-Cyclodextrin [2]Rotaxane Capable of Angiotensin†III Recognition.

Synthetic receptors selective for target peptides or proteins have received attention because of their potential applications in the separation of biomolecules and biomedical diagnostics. Herein, a [2]rotaxane-based functional monomer containing monocarboxylated α-cyclodextrin (α-CD) was synthesized, and its crosslinked polymers were evaluated to determine their binding ability to a model peptide, angiotensin III (Arg-Val-Tyr-Ile-His-Pro-Phe), containing an arginine (Arg) residue. The binding ability of the resulting polymers toward angiotensin III, angiotensin IV (Val-Tyr-Ile-His-Pro-Phe), and FMRF-amide (Phe-Met-Arg-Phe) was examined by the batch-binding assay and compared with that of control polymers, in which maleic acid-introduced α-CD was chemically crosslinked. The results suggest that the [2]rotaxane-based functional monomer in the crosslinked polymer contributes to the high affinity toward angiotensin III. The α-CD motion and rotation within the [2]rotaxane-based crosslinked polymer may be applicable for designing molecular recognition materials.