Reflecting recent work in the

DNA nanotechnology is an emerging field that promises fascinating opportunities for the manipulation and imaging of proteins on a cell surface. The key to progress is the ability to create a nucleic acid–protein junction in the context of living cells. >p/>

Herein is reported a covalent labelling reaction that installs a biostable
peptide nucleic acid (PNA) tag. The reaction proceeds within minutes and is specific for proteins carrying a 2 kDa coiled-coil peptide tag. Once installed, the PNA label serves as a generic landing platform that enables the recruitment of fluorescent dyes via nucleic acid hybridization.

The researchers demonstrate the versatility of this approach by recruiting different fluorophores, assembling multiple fluorophores for increased brightness and achieving reversible labelling by way of toehold-mediated strand displacement. Additionally, they show that labelling can be carried out using two different coiled-coil systems, with epidermal growth factor receptor and endothelin receptor type B, on both HEK293 and CHO cells.

Finally, they apply the method to monitor internalization of epidermal growth factor receptor on CHO cells.