title: Guanine riboswitch variants from Mesoplasma florum selectively recognize 2'-deoxyguanosine.
abstract: Several mRNA aptamers have been identified in Mesoplasma florum that have sequence and structural features resembling those of guanine and adenine riboswitches. Two features distinguish these RNAs from established purine-sensing riboswitches. All possess shortened hairpin-loop sequences expected to alter tertiary contacts known to be critical for aptamer folding. The RNAs also carry nucleotide changes in the core of each aptamer that otherwise is strictly conserved in guanine and adenine riboswitches. Some aptamers retain the ability to selectively bind guanine or adenine despite these mutations. However, one variant type exhibits selective and high-affinity binding of 2'-deoxyguanosine, which is consistent with its occurrence in the 5' untranslated region of an operon containing ribonucleotide reductase genes. The identification of riboswitch variants that bind nucleosides and reject nucleobases reveals that natural metabolite-sensing RNA motifs can accrue mutations that expand the diversity of ligand detection in bacteria.
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, Yale University, PO Box 208103, New Haven, CT 06520-8103, USA.
authors.forename: Jane N
authors.initials: JN
authors.lastname: Kim
authors.forename: Adam
authors.initials: A
authors.lastname: Roth
authors.forename: Ronald R
authors.initials: RR
authors.lastname: Breaker
mesh_terms: D000225:Adenine / Q000737:chemistry; D052157:Aptamers, Nucleotide / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D003849:Deoxyguanosine / Q000378:metabolism; D045622:Entomoplasmataceae / Q000235:genetics* / Q000378:metabolism*; D014644:Genetic Variation; D006147:Guanine / Q000737:chemistry; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D017354:Point Mutation; D012329:RNA, Bacterial / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D012689:Sequence Homology, Nucleic Acid
chemical_list: D052157:Aptamers, Nucleotide; D012329:RNA, Bacterial; D006147:Guanine; D003849:Deoxyguanosine; D000225:Adenine