Supramolecular nucleotide hydrogel as an artificial carbonic anhydrase for CO2 sequestration

Natural metalloenzymes achieve remarkable catalytic efficiency through precisely organized metal-ligand active sites within protein scaffolds, yet synthetically recreating this complexity remains challenging. Herein, we present a supramolecular strategy mimicking the architecture and function of a natural metalloenzyme in non-proteinaceous system. Exploiting the self-assembly of 5′-GMP into hierarchical supramolecular structures as a structural and functional analog of protein matrices, a tetrahedral Zn(His)3(H2O) center is spontaneously stabilized within an organized nanofibrous hydrogel. Experimental analyses combined with molecular simulations, demonstrate that nucleotide-directed supramolecular confinement cooperatively stabilizes the biomimetic Zn(His)3(H2O) coordination environment, creating an enzyme-like catalytic pocket. This minimalistic yet robust design, combining metal complexes with supramolecular assemblies, yields an artificial enzyme built solely from native biomolecules that closely resembles carbonic anhydrase II architecturally and functionally. The resulting ZnHG hydrogel exhibits efficient esterase and CO2 hydration activity with thermal stability and recyclability. CO2 hydration promotes biomineralization into diverse metal carbonates under aqueous conditions, establishing supramolecular nucleotide hydrogels as a protein-free platform for artificial enzymology. Natural metalloenzymes exhibit high catalytic efficiency, but replicating their complexity synthetically remains challenging. Here, the authors present a supramolecular artificial enzyme that mimics natural metalloenzymes and enables efficient, recyclable carbon dioxide hydration catalysis.