Bioorthogonal Reactions

Bioorthogonal chemistries to image and label proteins

The site-specific incorporation of ncAAs with bioorthogonally reactive functional groups that subsequently allow rapid, chemoselective, site-specific labeling of the protein of interest (POI) with a custom-designed probe represents a technique with enormous potential.

This strategy provides a modular approach for installing diverse probes with a single genetic system, and also removes limitations that the translational machinery places on the size of probes.

We have developed various ncAAs that are able to engage in inverse electron-demand Diels-Alder cycloadditions (iEDDACs) and allow rapid and selective labeling of cell-surface and intracellular proteins in E. coli and mammalian cells. Furthermore, these approaches have found application for selectively inhibiting a specific target protein within living cells, via covalently tethering a promiscuous inhibitor to a specific enzyme.

We have recently developed a novel light-induced iEDDAC reactions between tetrazines and a cyclopropenone caged dibenzoannulated bicylo[6.1.0]nonyne probe (photo-DMBO). In-situ light activation of photo-DMBO conjugates allows rapid labeling of tetrazine-modified proteins in living E. coli. This new chemistry offers exciting opportunities to modify proteins in living cells in a spatio-temporally controlled manner.