Crystalline protein assemblies of polyhedra crystal (PhC) can be utilized as solid enzyme containers for long-term storage of enzymes with retention of their enzymatic activity. The enzymes can be released from the crystals at the optimum pH for the enzymatic activity by dissolution of the crystals using in vivo crystal engineering.

Cross-linking of protein crystals promotes disulfide-mediated nanotubes.

Protein crystals are formed via ordered arrangements of proteins, which assemble to form supramolecular structures. Here, we show a method for the assembly of supramolecular protein cages within a crystalline environment. The cages are stabilized by covalent cross-linking allowing their release via dissolution of the crystal. The high stability of the desiccated protein crystals allows cages to be constructed.

Protein assemblies can be designed for development of nano–bio materials. This has been achieved by modulating protein–protein interactions. However, fabrication of highly ordered protein assemblies remains challenging. Protein crystals, which have highly ordered arrangements of protein molecules, provide useful source matrices for synthesizing artificial protein assemblies. Here, we describe construction of a supramolecular filament structure by engineering covalent and non‐covalent interactions in a protein crystal. Performing in‐cell crystallization of Trypanosoma brucei cysteine protease cathepsin B (TbCatB), we achieved a precise arrangement of protein molecules while suppressing random aggregation due to disulfide bonds. We succeeded in synthesizing bundled filament from the crystals by autoxidation of cysteinyl thiols after the isolation of the crystals from living cells.

Protein assemblies can be designed for development of nano–bio materials. This has been achieved by modulating protein–protein interactions. However, fabrication of highly ordered protein assemblies remains challenging. Protein crystals, which have highly ordered arrangements of protein molecules, provide useful source matrices for synthesizing artificial protein assemblies. Here, we describe construction of a supramolecular filament structure by engineering covalent and non‐covalent interactions in a protein crystal. Performing in‐cell crystallization of Trypanosoma brucei cysteine protease cathepsin B (TbCatB), we achieved a precise arrangement of protein molecules while suppressing random aggregation due to disulfide bonds. We succeeded in synthesizing bundled filament from the crystals by autoxidation of cysteinyl thiols after the isolation of the crystals from living cells.