The extensive study of protein assemblies promotes the rapid development of bioscience and biotechnology.[1] Among these well-organized supramolecular structures, in vivo protein crystals have been utilized as universal nanoplatforms for a wide range of applications due to their highly ordered spatial arrangement of protein molecules as porous materials, and the preparation of protein crystals is conducted spontaneously in cells requiring no further purification. The porous protein crystals have been used as universal vessels for dye encapsulation, enzyme reactions, etc.[2,3] These examples suggest that protein crystals are an excellent platform for designing hybrid protein assembly materials.
However, the system is limited to only exogenous protein encapsulation and has not been applied to complicated reactions, such as NADH generation promoted by a series of protein assemblies. Protein crystals have shown great potential to encapsulate various substances, including fluorescent dyes and enzymes, which are essential for photosynthesis for energy applications. Also, the stable and rigid structure of protein crystals could provide a compact arrangement for photosensitizers and enzymes. Moreover, the mature structural characterization and co-crystallization techniques of protein crystals make it convenient to design, analyze, and optimize the hybrid system. Based on the above background, this research is to develop enzyme-coupled artificial catalytic systems based on hybrid protein crystals (Figure 1). We will encapsulate the enzyme formate dehydrogenase (FDH) and the photosensitizer eosin Y (EY) in polyhedra crystals (PhC) to promote light-induced NADH generation.