Activation of Protein Splicing by Protease‐ or Light‐Triggered O to N Acyl Migration

Protein splicing under control: Introduction of an O-acyl isomer of a peptide bond into the naturally split Ssp DnaE intein prevents protein trans splicing, which can be recovered upon triggering an O to N acyl shift by deprotection with protease or light (see scheme). This system allows the splicing of a bacterial toxin to be controlled in response to protease activity.