title: Roles of Mg2+ in TPP-dependent riboswitch.
abstract: We quantified the effect of Mg(2+) on thiamine pyrophosphate (TPP) binding to TPP-dependent thiA riboswitch RNA. The association constant of TPP binding to the riboswitch at 20 degrees C increased from 1.2 x 10(6) to 50 x 10(6) M(-1) as the Mg(2+) concentration increased from 0 to 1 mM. Furthermore, circular dichroic spectra under various conditions showed that 1 mM Mg(2+) induced a local structural change of the riboswitch, which might be pivotal for TPP binding. These results indicate that a physiological concentration of Mg(2+) can regulate TPP binding to the thiA riboswitch.
authors.affiliation: Frontier Institute for Biomolecular Engineering, Research (FIBER), Konan University, Higashinada-ku, Kobe, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Yamauchi
authors.forename: Daisuke
authors.initials: D
authors.lastname: Miyoshi
authors.forename: Takafumi
authors.initials: T
authors.lastname: Kubodera
authors.forename: Akira
authors.initials: A
authors.lastname: Nishimura
authors.forename: Susumu
authors.initials: S
authors.lastname: Nakai
authors.forename: Naoki
authors.initials: N
authors.lastname: Sugimoto
mesh_terms: D020121:5' Untranslated Regions; D000241:Adenosine / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D002942:Circular Dichroism; D017124:Conserved Sequence; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D005786:Gene Expression Regulation; D007700:Kinetics; D008274:Magnesium / Q000378:metabolism* / Q000494:pharmacology / Q000502:physiology; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D012313:RNA / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D017423:Sequence Analysis, RNA; D012689:Sequence Homology, Nucleic Acid; D013696:Temperature; D013835:Thiamine Pyrophosphate / Q000378:metabolism*; D017186:Titrimetry; D014158:Transcription, Genetic
chemical_list: D020121:5' Untranslated Regions; D012313:RNA; D008274:Magnesium; D000241:Adenosine; D013835:Thiamine Pyrophosphate