Crystal structure of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) frameshifting pseudoknot

SARS-CoV-2 produces two long viral protein precursors from one open reading frame using a highly conserved RNA pseudoknot that enhances programmed -1 ribosomal frameshifting. The 1.3 angstrom-resolution X-ray structure of the pseudoknot reveals three coaxially stacked helices buttressed by idiosyncratic base triples from loop residues. This structure represents a frameshift-stimulating state that must be deformed by the ribosome and exhibits base-triple-adjacent pockets that could be targeted by future small-molecule therapeutics.

Automated summary

SARS-CoV-2 uses a highly conserved RNA pseudoknot to enhance programmed -1 ribosomal frameshifting, resulting in the production of two viral protein precursors from one open reading frame. The 1.3 angstrom-resolution X-ray structure of the pseudoknot reveals three stacked helices supported by unique base triples, which could be targeted by potential small-molecule therapeutics.