Oligopeptide-CB[8] complexation with switchable binding pathways

Area of Science:

• Supramolecular Chemistry
• Chemical Biology

Background:

• Host-guest complexation is fundamental to supramolecular chemistry.
• Cucurbit[8]uril (CB[8]) is a macrocyclic host known for strong binding interactions.
• Oligopeptides can form complexes with CB[8], but their stoichiometry and assembly pathways require further elucidation.

Purpose of the Study:

• To investigate the binding stoichiometry of oligopeptides with cucurbit[8]uril (CB[8]).
• To understand the sequence-specific binding pathways of peptide-CB[8] association.
• To explore the potential for controlling self-assembly through tailored binding modes.

Main Methods:

• Systematic study of peptide-CB[8] association pathways.
• Analysis of binding stoichiometry (1:1 vs. 2:1).
• Diffusion-based characterization of complex formation.

Main Results:

• A phenylalanine-leucine dipeptide was observed to switch between 1:1 and 2:1 binding modes with CB[8].
• The presence of a 1:1 pairwise inclusion complex was confirmed under specific conditions.
• Differences in diffusion properties distinguished the various binding modes.

Conclusions:

• The binding stoichiometry of oligopeptide-CB[8] complexes can be modulated.
• This control over binding modes offers a method for designing custom supramolecular systems.
• Findings provide a versatile approach for directing self-assembly in supramolecular chemistry.