A Protein Needle Facilitates Encapsulation of Target Proteins via In-Cell Protein Crystallization

We have established a new method for encapsulating superfold green fluorescent protein (sfGFP) into polyhedra crystal (PhC) with high efficiency using a protein needle (PN). H1-sfGFP-PN, in which PN is fused to the C-terminus of H1-sfGFP, exhibits a 55 -fold increase in encapsulation of sfGFP relative to H1-sfGFP with the improvement provided by the synergistic effects of the H1-helix, PN, and the His-tag at the C-terminus of PN. This method is expected to provide useful materials based on encapsulation of various functional proteins.