A Bioorthogonal Post-modification of N6-Isopentenyl Adenosine i6A RNA in Live Cells

Selective methods for modulating RNA epigenetic modifications within living cells and organisms represent attractive techniques for investigating biological functions and medicinal application. In contrast to enzymatic methods, abiotic chemical modulation offers access to diverse new -to -natural functionalities. We herein report a visible light-assisted bioorthogonal reaction involving flavin mononucleotide, sodium azide, and blue light irradiation. In concert with previous chemical approaches mimicking the demodification pathway, our system functions as a powerful and selective post-modification enzyme that targets N6-prenyl adenosine i6A in RNA and enables the efficient construction of an artificial N6-cyanomethyl adenosine (cnm6A). Notably, most endogenous biomacromolecular functions, including other common RNA epigenetics, remained unaffected. Consequently, we have successfully modified i6A in tRNA to cnm6A in human cells and establish this system as a bona fide bioorthogonal reaction with potential applications in chemical biology and in -cell modulation.