biostudies-literatureGeng PDeutsche Forschungsgemeinschafte202203156https://www.ebi.ac.uk/biostudies/studies/S-EPMC10107640biostudies-literatureUnknown29(8)Two green fluorescent tetrazine-modified cyanine-styryl dyes were synthesized for bioorthogonal labelling of DNA by means of the Diels-Alder reaction with inverse electron demand. With DNA as target biopolymer the fluorescence of these dyes is released by two factors: (i) sterically by their interaction with DNA, and (ii) structurally via the conjugated tetrazine as quencher moiety. As a result, the reaction with bicyclononyne-modified DNA is significantly accelerated up to ≥284,000 M^-1  s^-1 , and the fluorescence turn-on is enhanced up to 560 by the two-factor fluorogenicity. These dyes are cell permeable even in low concentrations and undergo fluorogenic reactions with BCN-modified DNA in living HeLa cells. The two-factor fluorescence release improves the signal-to-Chemistry (Weinheim an der Bergstrasse, Germany)Two-Factor Fluorogenicity of Tetrazine-Modified Cyanine-Styryl Dyes for Bioorthogonal Labelling of DNA.PMC10107640Wa 1387/17-2 und GRK 2039/2Wagenknecht HARonicke FGeng PList EfalseTwo-Factor Fluorogenicity of Tetrazine-Modified Cyanine-Styryl Dyes for Bioorthogonal Labelling of DNA.Two green fluorescent tetrazine-modified cyanine-styryl dyes were synthesized for bioorthogonal labelling of DNA by means of the Diels-Alder reaction with inverse electron demand. With DNA as target biopolymer the fluorescence of these dyes is released by two factors: (i) sterically by their interaction with DNA, and (ii) structurally via the conjugated tetrazine as quencher moiety. As a result, the reaction with bicyclononyne-modified DNA is significantly accelerated up to ≥284,000 M^-1  s^-1 , and the fluorescence turn-on is enhanced up to 560 by the two-factor fluorogenicity. These dyes are cell permeable even in low concentrations and undergo fluorogenic reactions with BCN-modified DNA in living HeLa cells. The two-factor fluorescence release improves the signal-to-2023-01-01T00:00:00Z2023 Feb2025-04-26T04:57:03.535Z2025-04-06T11:21:32.454ZS-EPMC101076403636715210.1002/chem.202203156