Chemo-enzymatic synthesis of [2-¹³C, 7-¹⁵ N]-ATP for facile NMR analysis of RNA

We report the efficient chemo-enzymatic synthesis of an [2-¹³C, 7-¹⁵N]-adenosine 5′-triphosphate building block for incorporation into RNA via T7 RNA polymerase-based in vitro transcription. Such atom-specific labeling alleviates spectral crowding and simplifies the analysis of large RNAs by solution NMR spectroscopy. Applications to probe adenosine C2 and N7 sites in a large 61 nucleotide viral RNA with two- and three-dimensional NMR experiments are demonstrated. Graphic abstract: