Protein Nanoparticle Formation Using a Circularly Permuted α-Helix-Rich Trimeric Protein.

We here report the production of highly spherical protein nanoparticles based on the domain-swapping oligomerization of a circularly permuted trimeric protein, major histocompatibility complex (MHC) class II associated chaperonin. The size distribution of the nanoparticles can be adjusted to between 40 and 100 nm in diameter, and thus, these particles are suitable as drug carriers following purification under basic conditions. Our approach involves no harsh treatments and could provide an alternative approach for protein nanoparticle formation.