Engineered fluorescence tags for in vivo protein labelling
In vivo protein labelling with a peptide tag–fluorescent probe system is an important chemical biology strategy for studying protein distribution, interaction and function. A variety of engineered tags have been developed to label proteins of interest (POIs), in which a protein or peptide tag is covalently linked to the POIs that can afford fluorescence signal under certain conditions. This review summarizes the current methodology in five categories, namely autofluorescent protein tags, peptide tags with a specific probe-binding amino acid sequence, peptide tags that can be further labelled by enzyme recognition, peptide tags that contain an enzymatic domain which can interact with small molecules or coenzymes, and peptide tags that can be labelled with probes through natural or artificial protein–protein interaction. The principles and application of each tool are also reviewed.