A metal-peptide capsule by multiple ring threading.

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Biomimicry

Background:

• Cavity creation is fundamental to biological functions, with nature utilizing peptide folding and ring threading for structures like enzyme pockets and viral capsids.
• Interlocked molecules are typically studied for molecular machinery or synthetic challenges, not specifically for cavity creation.

Purpose of the Study:

• To explore the potential of interlocked molecules for creating large, defined cavities.
• To investigate the self-assembly of metal-peptide rings into complex supramolecular architectures.
• To demonstrate a novel method for achieving significant molecular cavity creation.

Main Methods:

• Self-assembly of six C4-propeller-shaped metal-peptide rings, each comprising four oligopeptides and silver ions (Ag+).
• Utilizing multiple threading events to entangle the rings.
• Characterization of the resulting supramolecular structure and its cavity.

Main Results:

• Successful formation of a large, 4 nm-sized spherical capsular framework through the entanglement of six metal-peptide rings.
• The assembly involved twelve threading events, resulting in a complex topology with a crossing number of 24.
• The resulting structure functions as a significant molecular capsule with a substantial internal cavity.

Conclusions:

• The study demonstrates a successful strategy for creating large molecular capsules via the controlled threading of metal-peptide rings.
• This work highlights the potential of topological control in supramolecular chemistry for designing functional cavities.
• The achieved cavity creation represents a novel application of interlocked molecules beyond traditional uses in molecular machines or synthesis.