Photo‐SNAP‐Tag, a Light‐Regulated SNAP‐Tag Chemical Labeling System

Abstract

Methods that allow labelling and tracking of proteins during dynamic cellular events have been instrumental for understanding their function. Traditional methods for labeling proteins include fusion to fluorescent proteins or self‐labeling chemical tagging systems such as SNAP‐Tag or Halo‐Tag. These latter approaches allow bright fluorophores or other chemical moieties to be attached to a protein of interest though a small fusion tag. In this work, we sought to improve the versatility of self‐labeling chemical‐tagging systems by regulating their activity with light. We used light‐inducible dimerizers to reconstitute a split SNAP‐Tag (modified human O6‐alkylguanine‐DNA‐alkyltransferase, hAGT) protein, allowing tight light‐dependent control of chemical labeling. In addition, we generated a split SNAP‐Tag version that can efficiently self‐assemble, showing high labeling efficacy. We envision these tools will extend the versatility and utility of the SNAP‐Tag chemical system for protein labeling applications.