Orthogonal End Labelling of Oligonucleotides through Dual Incorporation of Click‐Reactive NTP Analogues

• Published in: Chembiochem : a European journal of chemical biology 2024-01, Vol.25 (1), p.e202300701-n/a
• Main Authors: Schönegger, Eva S., Crisp, Antony, Radukic, Marco, Burmester, Jonas, Frischmuth, Thomas, Carell, Thomas
• Format: Article
• Language: English
• Subjects: Aptamers; chemoenzymatic; Click Chemistry; click-functionalised nucleotides; DNA - chemistry; DNA nucleotidylexotransferase; Elongation; Fluorescence; Functional groups; Labeling; labelling; Nucleic acids; Oligonucleotides; Oligonucleotides - chemistry; Ribonucleic acid; RNA; RNA - chemistry
• ISSN: 1439-4227; 1439-7633
• DOI: 10.1002/cbic.202300701

Post‐synthetic modification of nucleic acid structures with clickable functionality is a versatile tool that facilitates many emerging applications, including immune evasion, enhancements in stability, fluorescent labelling, chemical 5′‐RNA‐capping and the development of functional aptamers. While certain chemoenzymatic approaches for 3′‐azido and alkynyl labelling are known, equivalent 5′‐strategies are either inefficient, complex, or require harsh chemical conditions. Here, we present a modular and facile technology to consecutively modify DNA and RNA strands at both ends with click‐modifiable functional groups. Our approach using γ‐modified ATP analogues facilitates T4 PNK‐catalysed 5′‐modification of oligonucleotides, a process that is compatible with TdT‐catalysed 3′‐elongation using 3′‐azido‐2′,3′‐ddGTP. Finally, we demonstrate that our approach is suitable for both oligo‐oligo ligations, as well ssDNA circularization. We anticipate that such approaches will pave the way for the synthesis of highly functionalised oligonucleotides, improving the therapeutic and diagnostic applicability of oligonucleotides such as in the realm of next‐generation sequencing. A new chemoenzymatic method involving dual incorporation of γ‐ and 3′‐modified NTPs allows sequential 5′‐ and 3′‐end labelling of DNA and RNA molecules.