Expanding the Enzymatic Polymerization Landscape by Lipid Mesophase Soft Nanoconfinement

Soft nanoconfinement can increase chemical reactivity in nature and has therefore led to considerable interest in transferring this universal feature to artificial biological systems. However, little is known about the underlying principles of soft nanoconfinement responsible for the enhancement of biochemical reactions. Herein we demonstrate how enzymatic polymerization can be expanded, optimized, and engineered when carried out under soft nanoconfinement mediated by lipidic mesophases. By systematically varying the water content in the mesophase and thus the diameter of the confined water nanochannels, we show higher efficiency, turnover rate, and degrees of polymerization as compared to the bulk aqueous solution, all controlled by soft nanoconfinement effects. Furthermore, we exploit the unique properties of unfreezing soft nanoconfined water to perform the first enzymatic polymerization at -20 degrees C in pure aqueous media. These results underpin lipidic mesophases as a versatile host system for chemical reactions and promote them as an original and unexplored platform for enzymatic polymerization. The enzymatic synthesis of dextran in lipidic mesophase catalyzed by the enzyme dextransucrase DSR-M not only yields polymers at 30 degrees C that are six times longer than in bulk solution at identical concentrations of reactants, but also allows the reaction to be carried out in subzero liquid water at temperatures as low as -20 degrees C.image