Synthetic Virus-like Particles for Glutathione Biosynthesis

Protein-based nanocompartments found in nature have inspired the development of functional nanomaterials for a range of applications including delivery of catalytic activities with therapeutic effects. As glutathione (GSH) plays a vital role in metabolic adaptation and many diseases are associated with its deficiency, supplementation of GSH biosynthetic activity might be a potential therapeutic when delivered directly to the disease site. Here, we report the successful design and production of active nanoreactors capable of catalyzing the partial or complete pathway for GSH biosynthesis, which was realized by encapsulating essential enzymes of the pathway inside the virus-like particle (VLP) derived from the bacteriophage P22. These nanoreactors are the first examples of nanocages specifically designed for the biosynthesis of oligomeric biomolecules. A dense packing of enzymes is achieved within the cavities of the nanoreactors, which allows us to study enzyme behavior, in a crowded and confined environment, including enzymatic kinetics and protein stability. In addition, the biomedical utility of the nanoreactors in protection against oxidative stress was confirmed using an in vitro cell culture model. Given that P22 VLP capsid was suggested as a potential liver-tropic nanocarrier in vivo, it will be promising to test the efficacy of these GSH nanoreactors as a novel treatment for GSH-deficient hepatic diseases.