Selective binding of choline by a phosphate-coordination-based triple helicate featuring an aromatic box

Area of Science:

• Supramolecular Chemistry
• Biomimetic Chemistry
• Molecular Recognition

Background:

• Proteins utilize specific cavities for selective guest capture.
• Molecular recognition principles like self-assembly and complementarity guide receptor design.
• The choline-binding protein ChoX demonstrates selective binding through a dual-site mechanism.

Purpose of the Study:

• To design and synthesize a biomimetic receptor that mimics the selective binding of the choline-binding protein ChoX.
• To investigate the binding mode and selectivity of the novel receptor for choline and its analogues.
• To develop a fluorescence displacement sensor for discriminating choline and related compounds.

Main Methods:

• Self-assembly of a triple anion helicate (host 2).
• X-ray crystallography and Density Functional Theory (DFT) for structural elucidation.
• Nuclear Magnetic Resonance (NMR) and fluorescence spectroscopy for binding and selectivity studies.

Main Results:

• A self-assembled triple anion helicate (host 2) with a cavity structure similar to ChoX was successfully synthesized.
• Host 2 exhibits a unique dual-site-binding mode for choline.
• Host 2 demonstrates high selectivity for choline over its derivatives, mimicking ChoX's selectivity.
• Host 2 functions as an effective fluorescence displacement sensor for discriminating choline, acetylcholine, L-carnitine, and glycine betaine.

Conclusions:

• The designed biomimetic receptor effectively mimics the natural protein's binding mechanism and selectivity.
• The dual-site-binding mode is crucial for achieving high selectivity for choline.
• The developed receptor holds potential as a sensitive sensor for choline and related biomolecules.