Metal-α-Helix Peptide Frameworks.

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Biomimetic Chemistry

Background:

• Metal-peptide frameworks (MPFs) are an emerging class of metal-organic frameworks.
• Limited MPFs exist with secondary structures and natural amino acid side chains for accurate metalloprotein mimicry.

Purpose of the Study:

• To design a robust and modular strategy for creating MPFs with biomimetic metal sites.
• To explore the impact of peptide sequence variation on framework structure and metal coordination.

Main Methods:

• Designed short α-helical peptides incorporating Glu and His residues for metal binding.
• Utilized mutagenesis of single amino acids to generate a library of peptide variants.
• Characterized framework structures using single-crystal X-ray diffraction.

Main Results:

• Successfully generated diverse MPFs with varying metal node coordination geometries and compositions using Co(II).
• 16 out of 20 variants were structurally characterized, revealing noncovalent interactions' influence on metal coordination spheres.
• Demonstrated ligand-triggered conformational changes in one variant, mimicking metalloprotein dynamic behavior.
• Showcased framework assembly with multiple metal ions (Mn(II), Fe(II), Cu(II), Zn(II)), confirming the approach's generality.

Conclusions:

• The developed peptide-based strategy provides an accessible platform for engineering biomimetic metal centers in porous materials.
• The modularity and ease of synthesis facilitate the study and application of MPFs in areas like catalysis and separations.