Conserved catalytic motifs encode enzyme-like supramolecular peptide assemblies.

A seven-residue fragment derived from the active site of carbonic anhydrase spontaneously forms Zn²⁺-binding amyloid fibrils that catalyze carbon dioxide hydration with catalytic efficiencies surpassing previous carbonic anhydrase mimics and approaching those of natural enzymes. Cryo-electron microscopy at 2.2 Å resolution, supported by PAC spectroscopy, solid-state NMR, molecular dynamics simulations, and QM/MM calculations, revealed a supramolecular active site that recapitulates key structural and mechanistic features of the enzyme despite arising from a fundamentally different protein fold. Minimal sequence modifications further increased activity to 1.3 × 10⁶ M⁻¹ s⁻¹. Extending this strategy to a conserved superoxide dismutase motif yielded copper-binding amyloids with near diffusion-limited activity, demonstrating that conserved catalytic motifs encode sufficient information to construct highly active supramolecular active sites independently of the globular protein fold. More broadly, they demonstrate that complex catalytic function can emerge from remarkably simple self-assembling peptide architectures, providing an experimentally tractable framework for investigating the fundamental principles that underlie enzymatic catalysis.