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Modified pyrimidines specifically bind the purine riboswitch

Sunny D Gilbert1, Sarah J Mediatore, Robert T Batey

  • 1Department of Chemistry and Biochemistry, University of Colorado at Boulder, Campus Box 215, Boulder, Colorado 80309-0215, USA.

Journal of the American Chemical Society
|November 2, 2006
PubMed

Insights

The adenine-responsive purine riboswitch can also recognize modified pyrimidine compounds. This finding broadens our understanding of RNA-based genetic regulation in bacteria.

Area of Science:

  • Molecular Biology
  • Biochemistry
  • Genetics

Background:

  • Purine riboswitches are genetic elements in Gram-positive bacteria.
  • They regulate mRNA expression in response to guanine or adenine.
  • These elements are found in the 5'-untranslated regions of mRNA.

Purpose of the Study:

  • To investigate if the adenine-responsive purine riboswitch recognizes other types of compounds.
  • To characterize the binding of modified pyrimidines to the adenine-responsive RNA element.

Main Methods:

  • Isothermal titration calorimetry (ITC) was used to study binding thermodynamics.
  • X-ray crystallography was employed to determine the structures of RNA-ligand complexes.

Main Results:

  • The adenine-responsive RNA element specifically recognizes pyrimidine compounds.
  • Recognition occurs for pyrimidines with modifications at the 6- or 5,6-positions.
  • Binding is similar in fashion to that observed for purine compounds.

Conclusions:

  • The specificity of the adenine-responsive purine riboswitch is broader than previously known.
  • This RNA element can act as a sensor for both purine and modified pyrimidine compounds.
  • Findings expand the potential applications of riboswitches in synthetic biology and genetic control.

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