SARS-CoV-2 frameshifting pseudoknot RNA, molecular model. Programmed ribosomal frameshifting is the key event during translation of the SARS-CoV-2 RNA genome allowing synthesis of the viral RNA-dependent RNA polymerase and downstream viral proteins. An RNA pseudoknot is an RNA structure containing at least two stem-loop structures in which half of one stem is intercalated between the two halves of another stem.