Bistetrazine‐Cyanines as Double‐Clicking Fluorogenic Two‐Point Binder or Crosslinker Probes

• Published in: Chemistry : a European journal 2018-06, Vol.24 (35), p.8841-8847
• Main Authors: Kormos, Attila, Koehler, Christine, Fodor, Eszter A., Rutkai, Zsófia R., Martin, Madison E., Mező, Gábor, Lemke, Edward A., Kele, Péter
• Format: Article
• Language: English
• Subjects: Amino acids; bioorthogonal; Chemistry; Conjugation; Crosslinking; dyes/pigments; Emission; Fluorescence; fluorogenic probes; noncanonical amino acid; peptides; Probes; Proteins; Quenching; Reagents; Synthesis
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201800910

Fluorogenic probes can be used to minimize the background fluorescence of unreacted and nonspecifically adsorbed reagents. The preceding years have brought substantial developments in the design and synthesis of bioorthogonally applicable fluorogenic systems mainly based on the quenching effects of azide and tetrazine moieties. The modulation power exerted by these bioorthogonal motifs typically becomes less efficient on more conjugated systems; that is, on probes with redshifted emission wavelength. To reach efficient quenching, that is, fluorogenicity, even in the red range of the spectrum, we present the synthesis, fluorogenic, and conjugation characterization of bistetrazine‐cyanine probes with emission maxima between 600 and 620 nm. The probes can bind to genetically altered proteins harboring an 11‐amino acid peptide tag with two appending cyclooctyne motifs. Moreover, we also demonstrate the use of these bistetrazines as fluorogenic, covalent cross‐linkers between monocyclooctynylated proteins. Clear and precise: The synthesis, fluorogenic, and conjugation characteristics of two new bistetrazine‐cyanine probes are presented. The probes can bind to genetically altered proteins harboring an 11‐amino acid peptide tag with two appending cyclooctyne motifs. The fluorogenic cross‐linking potential of the probes is also presented with monocyclooctynylated proteins.