A Closed Cavity Strategy for Selective Dipeptide Binding by a Polyaromatic Receptor in Water

Area of Science:

• Supramolecular Chemistry
• Chemical Sensing
• Organic Chemistry

Background:

• Peptide recognition is challenging due to amino acid diversity and hydration.
• Existing synthetic receptors often use open cavities, limiting selectivity.
• Developing selective peptide sensors is crucial for various applications.

Purpose of the Study:

• To design and demonstrate a synthetic receptor for selective dipeptide recognition.
• To investigate the binding mechanism and selectivity of the receptor.
• To explore the potential of the receptor in chemical sensing applications.

Main Methods:

• Synthesis of a polyaromatic receptor with a closed hydrophobic cavity.
• Selective binding studies of phenylalanine dipeptide in aqueous solutions.
• Characterization using Nuclear Magnetic Resonance (NMR) and Mass Spectrometry (MS).
• Isothermal Titration Calorimetry (ITC) for thermodynamic analysis.

Main Results:

• The receptor selectively binds phenylalanine dipeptide from a mixture.
• Binding is achieved through CH-π and hydrogen-bonding interactions within the closed cavity.
• High selectivity was observed even in the presence of other dipeptides and aspartame.
• ITC revealed strong, enthalpically and entropically favorable binding (Ka = 1.1 × 10^5 M^-1).
• The receptor system enables emission detection of the dipeptide.

Conclusions:

• A closed cavity strategy enables highly selective dipeptide recognition.
• The developed receptor demonstrates robust binding and selectivity for phenylalanine dipeptide.
• This approach offers a promising platform for developing sensitive peptide detection systems.