Studies of Highly-Ordered Heterodiantennary Mannose/Glucose-Functionalized Polymers and Concanavalin A Protein Interactions Using Isothermal Titration Calorimetry

• Published in: Biomacromolecules Vol. 16; no. 12; pp. 4013 - 4021
• Main Authors: Loka, Ravi S, McConnell, Matthew S, Nguyen, Hien M
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 14.12.2015
• Subjects: Binding Sites; Calorimetry - methods; Carbohydrate Conformation; Concanavalin A - chemistry; Glucose - chemistry; Kinetics; Mannose - chemistry; Polymerization
• ISSN: 1525-7797; 1526-4602
• DOI: 10.1021/acs.biomac.5b01380

Preparations of the highly ordered monoantennary, homofunctional diantennary, and heterofunctional diantennary neoglycopolymers of α-d-mannose and β-d-glucose residues were achieved via ring-opening metathesis polymerization. Isothermal titration calorimetry measurements of these synthetic neoglycopolymers with Concanavalin A (Con A), revealed that heterofunctional diantennary architectures bearing both α-mannose and nonbinding β-glucose units, poly­(Man-Glc), binds to Con A (K a = 16.1 × 106 M–1) comparably to homofunctional diantennary neoglycopolymer (K a = 30 × 106 M–1) bearing only α-mannose unit, poly­(Man-Man). In addition, poly­(Man-Glc) neoglycopolymer shows a nearly 5-fold increasing in binding affinity compared to monoantennary neoglycopolymer, poly­(Man). Although the exact mechanism for the high binding affinity of poly­(Man-Glc) to Con A is unclear, we hypothesize that the α-mannose bound to Con A might facilitate interaction of β-glucose with the extended binding site of Con A due to the close proximity of β-glucose to α-mannose residues in the designed polymerizable scaffold.