Tailoring Artificial Hydration Microenvironments in Covalent Organic Frameworks for Enhanced Enzymatic Catalysis in...

Hydration at biological interfaces plays a crucial role in enzyme function by stabilizing structures and driving conformational dynamics essential for catalysis. However, preserving these delicate hydration microenvironments in organic solvents remains challenging, undermining nonaqueous enzymatic catalysis and impeding industrial biocatalytic applications. Here, we tailored artificial hydration-like microenvironments for enzymes by integrating flexible oligo(ethylene oxide) chains, rich in hydrogen-bonding acceptors, into the confined channels of covalent organic frameworks (COFs). These engineered microenvironments promote multiple hydrogen-bond interactions between the encapsulated enzyme and the pore walls, significantly enhancing enzyme activity and stability in organic media. Notably, the encapsulated enzyme exhibited approximately 13-fold higher conversion than the free enzyme under 0% relative humidity (RH), while maintaining high performance across a wide humidity range. Unlike the fragile natural hydration layer, this hydration-like environment engineered within the confined nanochannels is stable, effectively preserving enzyme activity in polar solvents, while also resisting elevated temperature. Molecular dynamics (MD) simulations reveal that the multiple hydrogen bond-mediated microenvironment enhances the local conformational flexibility of enzyme and stabilizes its catalytic active center. Furthermore, the versatility of this approach is demonstrated in the lipase-catalyzed regioselective synthesis of active pharmaceutical intermediates. This work establishes an effective strategy for constructing robust hydration-like microenvironments, advancing the design of efficient biocatalysts in nonaqueous systems.