Amino acids with fluorescent tetrazine ethers as bioorthogonal handles for peptide modification. Issue 23 (12th May 2022)

• Record Type: Journal Article
• Authors: Ros, Enric; Bellido, Marina; Matarin, Joan A.; Gallen, Albert; Martínez, Manuel; Rodríguez, Laura; Verdaguer, Xavier; Ribas de Pouplana, Lluís; Riera, Antoni
• Is Part Of: RSC advances. Volume 12:Issue 23(2022)
• Page Start: 14321
• Page End: 14327
• Publication Date: 2022-05-12
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d2ra02531k
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : Octreotide derivatized with the fluorogenic amino acid 6-methyltetratrazinyl tryosine. Emission spectra before and after the iEDDA cycloaddition. Abstract : A set of 3-bromo-1, 2, 4, 5-tetrazines with three distinct substitutions have been used as reagents for late-stage functionalization of small molecules through nucleophilic aromatic substitution. Spectroscopic studies of the products obtained proved that tetrazine ethers are intrinsically fluorescent. This fluorescence is lost upon inverse Electron-Demand Diels–Alder (iEDDA) cycloaddition with strained alkenes. Tetrazine-phenol ethers are rather interesting because they can undergo rapid iEDDA reactions with a second order rate constant ( k 2 ) compatible with bioorthogonal ligations. As a showcase, l -tyrosine was derivatized with 3-bromo-6-methyl-1, 2, 4, 5-tetrazine and coupled to the peptide drug octreotide. This peptide was detected in cellular flow cytometry, and its fluorescence turned off through a bioorthogonal iEDDA cycloaddition with a strained alkene, showing for the first time the detection and reactivity of intrinsically fluorescent tetrazines in a biologically relevant context. The synthesis and characterization of fluorescent tetrazine ethers with bioorthogonal applicability pave the way for the generation of useful compounds for both detection and bioconjugation in vivo .