Intracellular protein cyclization catalyzed by exogenously transduced Streptococcus pyogenes sortase A

Streptococcus pyogenes sortase A (SpSrtA) was transduced into mammalian cells. Then SpSrtA-mediated intracellular circularization of a model protein was confirmed in a time and dose-dependent manner by Western blotting analysis. Direct transduction of SpSrtA is expected to be a strong tool for more conditional specific protein modification in mammalian cells.