Enzyme-Induced Nanocavity Formation in Leaf-shaped Zeolitic Imidazolate Frameworks for Functional Entrapment of Carbonic Anhydrase

Immobilizing carbonic anhydrases for CO₂ hydration holds great promise for efficient carbon capture. However, understanding how immobilization affects enzyme activity and host material structure is crucial for advancing this strategy. Here, we investigate the structural and functional consequences of entrapping Persephonella marina carbonic anhydrase (PmCA) within leaf-shaped zeolitic imidazolate frameworks (ZIF-L). ZIF-L was selected due to its uniform morphology, large surface area, and mild synthesis conditions, which support reproducibility and enable high-resolution structural characterization. Our results reveal that PmCA retains its activity, therefore its structural integrity, after entrapment. Interestingly, while ZIF-L retains crystallinity, it appears to adapt to the enzyme by forming nanocavities of approximately 5 nm in size, remarkably similar to the dimensions of PmCA, suggesting a host response during synthesis to uptake the biomolecule. By integrating detailed structural analysis with functional assay, this study uncovers insights into the underlying structural phenomenon, advancing our understanding on enzyme-incorporated biocatalytic systems.