Frequently the primary structure encodes motifs that are of functional importance. Some examples of sequence motifs are: the C/D
and H/ACA boxes
of snoRNAs, Sm binding site found in spliceosomal RNAs such as U1, U2, U4, U5, U6, U12 and U3, the Shine-Dalgarno sequence,
the Kozak consensus sequence
and the RNA polymerase III terminator.