Figure 1.

Structure and biological properties of mRNA 5′ cap analogs studied in this work. (A) Schematic structure of mRNA including its 5′ end. (B) Structure of β-S-ARCA (m₂^7,2′-OGpp_SpG) and its asymmetric phosphorothioate residue. (C) Equilibrium association constants of cap/eIF4E complexes³⁹ and relative translation efficiency of capped mRNAs in HC11 cells³¹ for ARCA and both diastereomers of β-S-ARCA. (D) Structures of di- and trinucleotide cap analogs studied in this work along with β-S-ARCA (PDB codes for the reported cap-eIF4E complex are provided under each cap formula). Asterisks (*) indicate stereogenic P atoms that generate D1 and D2 isomers.