Fluorescence Quenching Effects of Tetrazines and Their Diels–Alder Products: Mechanistic Insight Toward Fluorogenic Efficiency

Brismar Pinto-Pacheco, William P. Carbery, Sameer Khan, Daniel B. Turner, Daniela Buccella

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

Inverse electron demand Diels–Alder reactions between s-tetrazines and strained dienophiles have numerous applications in fluorescent labeling of biomolecules. Herein, we investigate the effect of the dienophile on the fluorescence enhancement obtained upon reaction with a tetrazine-quenched fluorophore and study the possible mechanisms of fluorescence quenching by both the tetrazine and its reaction products. The dihydropyridazine obtained from reaction with a strained cyclooctene shows a residual fluorescence quenching effect, greater than that exerted by the pyridazine arising from reaction with the analogous alkyne. Linear and ultrabroadband two-dimensional electronic spectroscopy experiments reveal that resonance energy transfer is the mechanism responsible for the fluorescence quenching effect of tetrazines, whereas a mechanism involving more intimate electronic coupling, likely photoinduced electron transfer, is responsible for the quenching effect of the dihydropyridazine. These studies uncover parameters that can be tuned to maximize fluorogenic efficiency in bioconjugation reactions and reveal that strained alkynes are better reaction partners for achieving maximum contrast ratio.

Original languageEnglish
Pages (from-to)22140-22149
Number of pages10
JournalAngewandte Chemie - International Edition
Volume59
Issue number49
DOIs
StatePublished - 1 Dec 2020
Externally publishedYes

Keywords

  • 2D electronic spectroscopy
  • FRET
  • photoinduced electron transfer
  • quenching mechanisms
  • tetrazine

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