At present it is difficult to interpret these results. One explanation could be that C24 or other L2 nucleotides also play a role in refolding of the pseudoknot after ribosome passage. It can be envisaged that a faster refolding pseudoknot might be a more efficient frameshifter, because in order to cause a frameshift, a stable pseudoknot needs to be regenerated before it encounters the next ribosome.