Carbohydrate-protein interactions by "clicked" carbohydrate self-assembled monolayers

Area of Science:

• Carbohydrate chemistry
• Biomolecular interactions
• Surface science

Background:

• Carbohydrate-protein interactions are crucial in biological processes.
• Developing stable and specific carbohydrate surfaces is essential for their study.
• Click chemistry offers a versatile tool for surface functionalization.

Purpose of the Study:

• To fabricate carbohydrate self-assembled monolayers (SAMs) using click chemistry.
• To investigate the specific binding of carbohydrate SAMs with proteins.
• To establish a platform for high-throughput analysis of carbohydrate-protein interactions.

Main Methods:

• Utilized Huisgen 1,3-dipolar cycloaddition (click chemistry) to immobilize azido sugars (mannose, lactose, alpha-Gal) onto gold surfaces.
• Employed preformed SAM templates with alkyne terminal groups for anchoring sugars.
• Characterized carbohydrate SAMs and their interactions using Surface Plasmon Resonance (SPR), Quartz Crystal Microbalance (QCM), Atomic Force Microscopy (AFM), and electrochemistry.

Main Results:

• Successfully fabricated well-packed, stable, and rigid carbohydrate SAMs.
• Demonstrated specific binding of mannose, lactose, and alpha-Gal SAMs to their respective binding partners (Con A, ECL, anti-Gal).
• Quantified apparent affinity constants for these interactions, showing high specificity and low non-specific adsorption.

Conclusions:

• Clicked carbohydrate SAMs provide a potent and specific platform for analyzing carbohydrate-protein interactions.
• The combination of carbohydrate SAMs with label-free QCM or SPR is effective for high-throughput characterization.
• This approach complements existing methods like ITC and ELISA, offering valuable insights into glycobiological processes.