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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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5' Untranslated Regions
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Adenosine / metabolism
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Base Sequence
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Binding Sites
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Circular Dichroism
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Conserved Sequence
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Dose-Response Relationship, Drug
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Electrophoresis, Polyacrylamide Gel
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Gene Expression Regulation
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Kinetics
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Magnesium / metabolism*
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Magnesium / pharmacology
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Magnesium / physiology
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Models, Molecular
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Molecular Sequence Data
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Protein Binding
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RNA / chemistry
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RNA / classification
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RNA / genetics
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RNA / metabolism*
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Sequence Analysis, RNA
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Sequence Homology, Nucleic Acid
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Temperature
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Thiamine Pyrophosphate / metabolism*
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Titrimetry
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Transcription, Genetic
Substances
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5' Untranslated Regions
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RNA
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Magnesium
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Adenosine
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Thiamine Pyrophosphate