Exceptionally stable, redox-active supramolecular protein assemblies with emergent properties

Area of Science:

• Biomolecular engineering
• Materials science
• Protein self-assembly

Background:

• Protein-protein interactions are key to designing functional supramolecular architectures.
• RIDC3, a cytochrome cb562 variant, self-assembles via Zn(2+) coordination into 1D nanotubes and 2D arrays.
• Understanding and controlling protein assembly offers opportunities for novel material properties.

Purpose of the Study:

• To investigate the chemical and thermal stability of RIDC3 supramolecular assemblies.
• To explore the potential for controlled nanocrystal growth using these protein frameworks.
• To demonstrate a thermally induced crystalline-to-crystalline conversion in biomolecular assemblies.

Main Methods:

• Utilized Zn(2+) coordination for self-assembly of RIDC3 proteins into 1D and 2D structures.
• Assessed structural integrity in various organic solvents (THF, iPrOH) and at elevated temperatures.
• Investigated the templated growth of platinum (Pt(0)) nanocrystals on the RIDC3 assemblies.

Main Results:

• RIDC3 assemblies exhibited high stability in ≥90% organic solvents, unlike denatured monomers.
• 1D nanotubes and 2D arrays showed thermostability up to 70 °C and 90 °C, respectively.
• A thermally induced conversion of 1D nanotubes to 2D arrays was observed above 70 °C.
• Zn-directed RIDC3 assemblies successfully templated the growth of Pt(0) nanocrystals.

Conclusions:

• Metal-mediated self-assembly significantly enhances the stability of RIDC3 proteins.
• RIDC3 assemblies provide a robust platform for controlled nanocrystal synthesis.
• The observed thermal conversion highlights unique dynamic properties of biomolecular assemblies.