In-Cell Engineering of Protein Crystals into Hybrid Solid Catalysts for Artificial Photosynthesis

The emergence of protein-based crystalline materialsoffers promisingopportunities in enzyme immobilization. However, the current systemsused for encapsulation of protein crystals are limited to either exogenoussmall molecules or monomeric proteins. In this work, polyhedra crystalswere used to simultaneously encapsulate the foreign enzymes FDH andthe organic photocatalyst eosin Y. These hybrid protein crystals areprepared easily by cocrystallization within a cell without a requirement for complex purification processes becausethey spontaneously form 1 & mu;m scale solid particles. After immobilizationwithin protein crystals, the recombinant FDH is recyclable and thermallystable and maintains 94.4% activity compared to the free enzyme. Inaddition, the incorporation of eosin Y endows the solid catalyst withCO(2)-formate conversion activity based on a cascadereaction. This work indicates that engineering protein crystals byboth in vivo and in vitro strategieswill provide robust and environmentally friendly solid catalysts forartificial photosynthesis.

Automated summary

The emergence of protein-based crystalline materials provides promising opportunities for enzyme immobilization. This study demonstrates the use of polyhedra crystals to simultaneously encapsulate the foreign enzymes FDH and the organic photocatalyst eosin Y. These hybrid protein crystals, prepared easily by cocrystallization within a cell, form solid particles at a scale of 1 μm without the need for complex purification processes. The immobilized FDH within protein crystals exhibits recyclability, thermal stability, and maintains 94.4% activity compared to the free enzyme. Additionally, the incorporation of eosin Y enables CO(2)-formate conversion activity in the solid catalyst through a cascade reaction. This work highlights the potential of engineering protein crystals for the development of robust and environmentally friendly solid catalysts for artificial photosynthesis.