Coronavirus 3' stem-loop II-like motif (s2m)

The Coronavirus 3' stem-loop II-like motif (also known as s2m) is a secondary structure motif identified in the 3'untranslated region (3'UTR) of astrovirus, coronavirus and equine rhinovirus genomes. Its function is unknown, but various viral 3' UTR regions have been found to play roles in viral replication and packaging.

This motif appears to be conserved in both nucleotide sequence and secondary structure folding indicating a strong evolutionary selection for its conservation. The presence of this conserved motif in these three different viral families is suggested to be the result of at least two separate recombination events.