PreQ1-II riboswitch
Encyclopedia
PreQ1-II riboswitches form a class of riboswitch
es that specifically bind pre-queosine1 (PreQ1), a precursor of the modified nucleoside queuosine
. They are found in certain species of Streptococcus
and Lactococcus
, and were originally identified as a conserved RNA secondary structure called the "COG4708 motif". 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.
Riboswitch
In molecular biology, a riboswitch is a part of an mRNA molecule that can directly bind a small target molecule, and whose binding of the target affects the gene's activity. Thus, an mRNA that contains a riboswitch is directly involved in regulating its own activity, in response to the...
es that specifically bind pre-queosine1 (PreQ1), a precursor of the modified nucleoside queuosine
Queuosine
Queuosine is a modified nucleoside that is present in certain tRNAs in bacteria and eukaryotes. Originally identified in E. coli, queuosine was found to occupy the first anticodon position of tRNAs for histidine, aspartic acid, asparagine and tyrosine. The first anticodon position pairs with the...
. They are found in certain species of Streptococcus
Streptococcus
Streptococcus is a genus of spherical Gram-positive bacteria belonging to the phylum Firmicutes and the lactic acid bacteria group. Cellular division occurs along a single axis in these bacteria, and thus they grow in chains or pairs, hence the name — from Greek στρεπτος streptos, meaning...
and Lactococcus
Lactococcus
Lactococcus is a genus of lactic acid bacteria that were formerly included in the genus Streptococcus Group N1. They are known as homofermentors meaning that they produce a single product, lactic acid in this case, as the major or only product of glucose fermentation...
, and were originally identified as a conserved RNA secondary structure called the "COG4708 motif". 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
PreQ1 riboswitch
The PreQ1-I riboswitch is a cis-acting element identified in bacteria which regulates expression of genes involved in biosynthesis of the nucleoside queuosine from GTP. This RNA element known as a riboswitch binds preQ1 , an intemediate in the queuosine pathway...
, 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.