S26: Nanobioreactors: encapsulating enzymes in viral capsids

The entrapment of enzymes in confined environments has become an attractive approach to many challenges in the field of biotechnology, including single enzyme experiments, protection from degradation, tissue targeting, and rate enhancement. The bacteriophage MS2 viral capsid offers a highly stable, easily modified, porous protein shell with great potential to encapsulate a wide variety of molecules. We have developed a simple charge-based approach to encapsulation of enzymes inside the MS2 capsid under mild conditions, greatly assisted by the addition of a protein stabilizing osmolyte trimethylamine-N-oxide. This osmolyte, which has been shown to prevent protein unfolding and aggregation, significantly enhances the yield of properly reassembled capsids. This technique confines enzymes inside the capsids with minimal effects on activity, as demonstrated with the model enzyme alkaline phosphatase. This system is now being applied to multiple enzymes and viral capsids with modified pores to answer fundamental biochemical questions and create targeted therapeutics.