PreQ1-II riboswitch

PreQ1-II riboswitches form a class of riboswitches that specifically bind pre-queosine₁ (PreQ₁), a precursor of the modified nucleoside queuosinecite journal |author=Meyer MM, Roth A, Chervin SM, Garcia GA, Breaker RR |title=Confirmation of a second natural preQ1 aptamer class in Streptococcaceae bacteria |journal=RNA |volume= |issue= |pages= |year=2008 |pmid=18305186 |doi=10.1261/rna.937308] . They are found in certain species of "Streptococcus" and "Lactococcus", and were originally identified as a conserved RNA secondary structure called the "COG4708 motif" [cite journal |author=Weinberg Z, Barrick JE, Yao Z, "et al" |title=Identification of 22 candidate structured RNAs in bacteria using the CMfinder comparative genomics pipeline |journal=Nucleic Acids Res. |volume=35 |issue=14 |pages=4809–19 |year=2007 |pmid=17621584 |doi=10.1093/nar/gkm487] . All known members of this riboswitch class appear to control members of COG4708 genes. These genes are predicted to encode membrane-bound proteins and have been proposed to be a transporter of preQ₁, or a related metabolite, based on their association with preQ₁-binding riboswitches. PreQ1-II riboswitches have no apparent similarities in sequence or structure to preQ1-I riboswitches, a previously discovered class of preQ₁-binding riboswitches. PreQ₁ thus joins S-adenosylmethionine as the second metabolite to be found that is the ligand of more than one riboswitch class.

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