A novel strategy to modulate the assembly and trans-splicing activity of the Ssp DnaE split-intein was achieved by introducing two photolabile protecting groups onto the backbone of the C-intein polypeptide. This modification was not only able to efficiently block the trans-splicing activity, but also reduce significantly the binding affinity constant between the C- and N-intein fragments. The original activity of the wild-type split intein could be fully recovered by brief exposure to UV light.