A Kinetic and Fluorogenic Enhancement Strategy for Labeling of Nucleic Acids

Abstract

Chemical modification of nucleic acids in living cells can be sterically hindered by tight packing of bioorthogonal functional groups in chromatin. To address this limitation, we report here a dual enhancement strategy for nucleic acid-templated reactions utilizing a fluorogenic intercalating agent capable of undergoing inverse electron-demand Diels-Alder (IEDDA) reactions with DNA containing 5-vinyl-2'-deoxyuridine (VdU) or RNA containing 5-vinyl-uridine (VU). Reversible high-affinity intercalation of a novel acridinetetrazine conjugate "PINK" (K D = 5 � 1 μM) increases the reaction rate of tetrazine-alkene IEDDA on duplex DNA by 60 000-fold (590 M À 1 s À 1 ) as compared to the non-templated reaction. At the same time, loss of tetrazine-acridine fluorescence quenching renders the reaction highly fluorogenic and detectable under nowash conditions. This strategy enables live-cell dynamic imaging of acridine-modified nucleic acids in dividing cells.

Enhanced immunotherapy based on the synergistic click reaction-mediated chemotherapy and photothermal therapy for efficient tumor inhibition

“…Meanwhile, highly efficient reactions under mild reaction condition present significant promise for biomedical applications. Diverse reactions, including Staudinger ligation 30,31 , quadricylane ligation 32 , Diels-Alder reaction [33][34][35] , strain promoted azide-alkyne cycloaddition (SPAAC) [36][37][38] , Native chemical ligation (NCL) 39,40 etc, have been successfully used for bio-labeling and tracing applications. Recently, increasing reports have demonstrated the utilization of efficient reactions for therapeutic applications by disturbing or blocking the function of biomacromolecules.…”