Novel Adomet analogues as tools for enzymatic transfer of photo-crosslinkers and capturing RNA-protein interactions

Muttach F, Mäsing F, Studer A, Rentmeister A

Abstract

Elucidation of biomolecular interactions is of utmost importance in biochemistry. Photo‐cross‐linking offers the possibility to precisely determine RNA-protein interactions. However, despite the inherent specificity of enzymes, approaches for site‐specific introduction of photo‐cross‐linking moieties into nucleic acids are scarce. Methyltransferases in combination with synthetic analogues of their natural cosubstrate S‐adenosyl‐l‐methionine (AdoMet) allow for the post‐synthetic site‐specific modification of biomolecules. We report on three novel AdoMet analogues bearing the most widespread photo‐cross‐linking moieties (aryl azide, diazirine, and benzophenone). We show that these photo‐cross‐linkers can be enzymatically transferred to the methyltransferase target, that is, the mRNA cap, with high efficiency. Photo‐cross‐linking of the resulting modified mRNAs with the cap interacting protein eIF4E was successful with aryl azide and diazirine but not benzophenone, reflecting the affinity of the modified 5′ caps.