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Fluoride ion encapsulation by Mg2+ ions and phosphates in a fluoride riboswitch

Abstract

Significant advances in our understanding of RNA architecture, folding and recognition have emerged from structure–function studies on riboswitches, non-coding RNAs whose sensing domains bind small ligands and whose adjacent expression platforms contain RNA elements involved in the control of gene regulation. We now report on the ligand-bound structure of the Thermotoga petrophila fluoride riboswitch, which adopts a higher-order RNA architecture stabilized by pseudoknot and long-range reversed Watson–Crick and Hoogsteen A•U pair formation. The bound fluoride ion is encapsulated within the junctional architecture, anchored in place through direct coordination to three Mg2+ ions, which in turn are octahedrally coordinated to water molecules and five inwardly pointing backbone phosphates. Our structure of the fluoride riboswitch in the bound state shows how RNA can form a binding pocket selective for fluoride, while discriminating against larger halide ions. The T. petrophila fluoride riboswitch probably functions in gene regulation through a transcription termination mechanism.

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Figure 1: Sequence, binding affinity and structure of the sensing domain of the T. petrophila fluoride riboswitch in the ligand-bound state.
Figure 2: Details of long-range interactions within the structure of the T. petrophila fluoride riboswitch in the ligand-bound state.
Figure 3: Details of the fluoride ion binding site in the T. petrophila fluoride riboswitch in the ligand-bound state.

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Protein Data Bank

Data deposits

Atomic coordinates of the structure of the fluoride riboswitch in the bound state have been deposited in the RCSB Protein Data Bank under the accession code 4ENC for the native structure and 4ENB for the Ir(NH3)63+-containing structure of the fluoride-bound riboswitch, as well as 3VRS, 4ENA and 4EN5 for crystals of the complex soaked in Mn2+-, Cs+- and Tl+-containing solutions.

References

  1. Mironov, A. S. et al. Sensing small molecules by nascent RNA: a mechanism to control transcription in bacteria. Cell 111, 747–756 (2002)

    Article  CAS  Google Scholar 

  2. Winkler, W., Nahvi, A. & Breaker, R. R. Thiamine derivatives bind messenger RNAs directly to regulate bacterial gene expression. Nature 419, 952–956 (2002)

    Article  ADS  CAS  Google Scholar 

  3. Nudler, E. & Mironov, A. S. The riboswitch control of bacterial metabolism. Trends Biochem. Sci. 29, 11–17 (2004)

    Article  CAS  Google Scholar 

  4. Winkler, W. C. & Breaker, R. R. Regulation of bacterial gene expression by riboswitches. Annu. Rev. Microbiol. 59, 487–517 (2005)

    Article  CAS  Google Scholar 

  5. Serganov, A. & Patel, D. J. Ribozymes, riboswitches and beyond: regulation of gene expression without proteins. Nature Rev. Genet. 8, 776–790 (2007)

    Article  CAS  Google Scholar 

  6. Montange, R. K. & Batey, R. T. Riboswitches: emerging themes in RNA structure and function. Annu. Rev. Biophys. 37, 117–133 (2008)

    Article  CAS  Google Scholar 

  7. Serganov, A. et al. Structural basis for gene regulation by a thiamine pyrophosphate-sensing riboswitch. Nature 441, 1167–1171 (2006)

    Article  ADS  CAS  Google Scholar 

  8. Thore, S., Leinungdut, M. & Ban, N. Structure of the eukaryotic thiamine pyrophosphate riboswitch with its regulatory ligand. Science 312, 1208–1211 (2006)

    Article  ADS  CAS  Google Scholar 

  9. Lang, K., Rieder, R. & Micura, R. Ligand-induced folding of the thiM TPP riboswitch investigated by a structure-based fluorescence spectroscopic approach. Nucleic Acids Res. 35, 5370–5378 (2007)

    Article  CAS  Google Scholar 

  10. Anthony, P. C., Perez, C. F., Garcia-Garcia, C. & Block, S. M. Folding energy landscape of the thiamine pyrophosphate riboswitch aptamer. Proc. Natl Acad. Sci. USA 109, 1485–1489 (2012)

    Article  ADS  CAS  Google Scholar 

  11. Mironov, A. S. et al. Sensing small molecules by nascent RNA: a mechanism to control transcription in bacteria. Cell 111, 747–756 (2002)

    Article  CAS  Google Scholar 

  12. Serganov, A., Huang, L. & Patel, D. J. Coenzyme recognition and gene regulation by a flavin mononucleotide riboswitch. Nature 458, 233–237 (2009)

    Article  ADS  CAS  Google Scholar 

  13. Baker, J. L. et al. Widespread genetic switches and toxicity resistance proteins for fluoride. Science 335, 233–235 (2012)

    Article  ADS  CAS  Google Scholar 

  14. Mandal, M. et al. Riboswitches control fundamental biochemical pathways in Bacillus subtilis and other bacteria. Cell 113, 577–586 (2003)

    Article  CAS  Google Scholar 

  15. Batey, R. T., Gilbert, S. D. & Montange, R. K. Structure of a natural guanine-responsive riboswitch complexed with the metabolite hypoxanthine. Nature 432, 411–415 (2004)

    Article  ADS  CAS  Google Scholar 

  16. Serganov, A. et al. Structural basis for discriminative regulation of gene expression by adenine- and guanine-sensing mRNAs. Chem. Biol. 11, 1729–1741 (2004)

    Article  CAS  Google Scholar 

  17. Mandal, M. et al. A glycine-dependent riboswitch that uses cooperative binding to control gene expression. Science 306, 275–279 (2004)

    Article  ADS  CAS  Google Scholar 

  18. Huang, L., Serganov, A. & Patel, D. J. Structural insights into ligand recognition by a sensing domain of the cooperative glycine riboswitch. Mol. Cell 40, 774–786 (2010)

    Article  CAS  Google Scholar 

  19. Butler, E. B., Xiong, Y., Wang, J. & Strobel, S. A. Structural basis of cooperative ligand binding by the glycine riboswitch. Chem. Biol. 18, 293–298 (2011)

    Article  CAS  Google Scholar 

  20. Heikinheimo, P. et al. Toward a quantum-mechanical description of metal-assisted phosphoryl transfer in pyrophosphatase. Proc. Natl Acad. Sci. USA 98, 3121–3126 (2001)

    Article  ADS  CAS  Google Scholar 

  21. Auffinger, P., Hays, F. H., Westhof, E. & Ho, P. S. Halogen bonds in biological molecules. Proc. Natl Acad. Sci. USA 101, 16789–16794 (2004)

    Article  ADS  CAS  Google Scholar 

  22. Hanna, R. & Doudna, J. A. Metal ions in ribozyme folding and catalysis. Curr. Opin. Chem. Biol. 4, 166–170 (2000)

    Article  CAS  Google Scholar 

  23. Correll, C. C., Freeborn, B., Moore, P. B. & Steitz, T. A. Metals, motifs and recognition in the crystal structure of a 5S RNA domain. Cell 91, 705–712 (1997)

    Article  CAS  Google Scholar 

  24. Cate, J. H., Hanna, R. L. & Doudna, J. A. A magnesium ion core at the heart of a ribozyme domain. Nature Struct. Biol. 4, 553–558 (1997)

    Article  CAS  Google Scholar 

  25. Cromie, M. J., Shi, Y., Latifi, T. & Groisman, E. A. An RNA sensor for intracellular Mg2+. Cell 125, 71–84 (2006)

    Article  CAS  Google Scholar 

  26. Dann, C. E., III et al. Structure and mechanism of a metal-sensing regulatory RNA. Cell 130, 878–892 (2007)

    Article  CAS  Google Scholar 

  27. Pikovskaya, O. et al. Preparation and crystallization of riboswitch-ligand complexes. Methods Mol. Biol. 540, 115–128 (2009)

    Article  CAS  Google Scholar 

  28. Pape, T. & Schneider, T. R. HKL2MAP: a graphical user interface for phasing with SHELX programs. J. Appl. Cryst. 37, 843–844 (2004)

    Article  CAS  Google Scholar 

  29. Adams, P. D. et al. PHENIX: building new software for automated crystallographic structure determination. Acta Crystallogr. D 58, 1948–1954 (2002)

    Article  Google Scholar 

  30. Emsley, P. & Cowtan, K. Coot: model-building tools for molecular graphics. Acta Crystallogr. D 60, 2126–2132 (2004)

    Article  Google Scholar 

  31. Murshudov, G. N., Vagin, A. A. & Dodson, E. J. Refinement of macromolecular structures by the maximum-likelihood method. Acta Crystallogr. D 53, 240–255 (1997)

    Article  CAS  Google Scholar 

  32. Feig, A. L. & Uhlenbeck, O. C. in The RNA World 2nd edn (eds Gesteland, R. F., Cech, T. R. & Atkins, J. F. ) 287–319 (Cold Spring Harbor Laboratory Press, 1999)

    Google Scholar 

Download references

Acknowledgements

We thank J. Goldberg and C. Lima for discussion and insights, Y. Liu for recording imino proton NMR spectra, and the personnel of the synchrotron beamlines 24-ID-C/E at the Advanced Photon Source, Argonne National Laboratory for their assistance. This research was funded by NIH grant GM34504 to D.J.P.

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Authors

Contributions

A.R. generated and purified RNA constructs, grew diffraction quality crystals, collected synchrotron data sets and solved the structure of the fluoride riboswitch in the bound state under the supervision of D.J.P.; K.R.R. assisted in crystallographic aspects of the structure determination, including finding unique solutions to the positioning of the Mg and fluoride ions. D.J.P. wrote the manuscript with the assistance of the other authors, all of whom discussed the results and commented on the manuscript.

Corresponding author

Correspondence to Dinshaw J. Patel.

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The authors declare no competing financial interests.

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Ren, A., Rajashankar, K. & Patel, D. Fluoride ion encapsulation by Mg2+ ions and phosphates in a fluoride riboswitch. Nature 486, 85–89 (2012). https://doi.org/10.1038/nature11152

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