Cited research: Proc. Natl Acad. Sci. USA doi:10.1073/pnas.0914067107 (2010)

Fluorescent tags that can be attached to cellular proteins are an indispensable biological imaging tool, but are often large and can interfere with a protein's function. Smaller ones, meanwhile, can be toxic, as well as unreliable at labelling the protein of interest.

Alice Ting and her team at the Massachusetts Institute of Technology in Cambridge have developed a protein-labelling method involving small fluorescent tags that they say are less toxic and more specific. They engineered an enzyme from the bacterium Escherichia coli to join a blue fluorescent molecule to proteins modified to carry a specific amino-acid recognition sequence.

The authors were able to quickly tag specific groups of proteins inside living mammalian cells. C.L.