Sulfonated red and far-red rhodamines to visualize SNAP- and Halo-tagged cell surface proteins

Ramona Birke, Julia Ast, Dorien A. Roosen, Joon Lee, Kilian Roßmann, Christiane Huhn, Bettina Mathes, Michael Lisurek, David Bushir, Han Sun, Ben Jones, Martin Lehmann, Joshua Levitz, Volker Haucke, David Hodson, Johannes Broichhagen

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The (in)ability to permeate membranes is a key feature of chemical biology probes that defines their suitability for specific applications. Here we report sulfonated rhodamines that endow xanthene dyes with cellular impermeability for analysis of surface proteins. We fuse charged sulfonates to red and far-red dyes to obtain Sulfo549 and Sulfo646, respectively, and further link these to benzylguanine and choloralkane substrates for SNAP-tag and Halo-tag labelling. Sulfonated rhodamine-conjugated fluorophores maintain desirable photophysical properties, such as brightness and photostability. While transfected cells with a nuclear localized SNAP-tag remain unlabelled, extracellular exposed tags can be cleanly visualized. By multiplexing with a permeable rhodamine, we are able to differentiate extra- and intracellular SNAP- and Halo-tags, including those installed on the glucagon-like peptide-1 receptor, a prototypical class B G protein-coupled receptor. Sulfo549 and Sulfo646 also labelled transfected neurons derived from induced pluripotent stem cells (iPSCs), allowing STED nanoscopy of the axonal membrane. Together, this work provides a new avenue for rendering dyes impermeable for exclusive extracellular visualization via self-labelling protein tags. We anticipate that Sulfo549, Sulfo646 and their congeners will be useful for a number of cell biology applications where labelling of intracellular sites interferes with accurate surface protein analysis.
Original languageEnglish
Pages (from-to)5967-5980
JournalOrganic and Biomolecular Chemistry
Issue number30
Early online date21 Feb 2022
Publication statusE-pub ahead of print - 21 Feb 2022

ASJC Scopus subject areas

  • Biochemistry
  • Physical and Theoretical Chemistry
  • Organic Chemistry


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