Synthesis of RNA conjugates as bisubstrates for the study of transferases

Bisubstrate compounds are designed to mimic the interaction of enzymes with their two natural substrates. These molecules contain two moieties mimicking the two substrates linked together by a covalent bridge, which enhances both selectivity and potency. This review shows the synthesis and utility of RNA conjugates, particularly peptidyl–RNA and cofactor–RNA conjugates, as bisubstrate analogues for studying two major families of RNA transferases: Fem aminoacyl transferases involved in bacterial cell wall synthesis and m 6 A methyltransferases, which catalyze RNA methylation. The synthetic routes developed to access the RNA conjugates cover nucleoside and nucleotide chemistry, site-specific RNA modifications, and solid phase synthesis or chemoenzymatic processes as well as strategies of oligonucleotide late-stage functionalization. The bisubstrate molecules have been used not only as inhibitors of these transferases but also as valuable chemical tools for elucidating enzyme mechanisms and facilitating structural studies.