The PreQ1-II riboswitch was originally identified by bioinformatics as a conserved RNA-like structure called the "COG4708 motif" since it was found upstream of COG4708 genes in some Streptococcus and Lactococcus species [17621584]. Later, the COG4708 motif was shown to bind directly to preQ1 (pre-queuosine1 or 7-aminomethyl-7-deazaguanine), an intermediate of the queuosine pathway [18305186]. Queuosine is a modified nucleoside that is present in certain tRNAs in bacteria and eukaryotes. In bacteria, queuosine is either synthesized from GTP via a committed metabolic pathway [14660578] or it is salvaged from the environment via queuosine precursor-specific transport systems [20497229]. more

All known members of this riboswitch class appear to control members of COG4708 family genes. The COG4708 genes are predicted to encode the ECF-type transporter QueT for salvage of queuosine precursors, e.g. preQ1 [20497229]. PreQ1-II riboswitches have no apparent similarities in sequence or structure to another family of riboswitches with the same function (preQ1 riboswitch).