Quantitative Packaging of Active Enzymes into a Protein Cage

Genetic fusion of cargo proteins to a positively supercharged variant of green fluorescent protein enables their quantitative encapsulation by engineered lumazine synthase capsids possessing a negatively charged lumenal surface. This simple tagging system provides a robust and versatile means of creating hierarchically ordered protein assemblies for use as nanoreactors. The generality of the encapsulation strategy and its effect on enzyme function were investigated with eight structurally and mechanistically distinct catalysts.