Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

Direct nitration and azidation of aliphatic carbons by an iron-dependent halogenase

Abstract

Iron-dependent halogenases employ cis-halo-Fe(IV)-oxo (haloferryl) complexes to functionalize unactivated aliphatic carbon centers, a capability elusive to synthetic chemists. Halogenation requires (i) coordination of a halide anion (Cl or Br) to the enzyme's Fe(II) cofactor, (ii) coupled activation of O2 and decarboxylation of α-ketoglutarate to generate the haloferryl intermediate, (iii) abstraction of hydrogen (H•) from the substrate by the ferryl and (iv) transfer of the cis halogen as Cl• or Br• to the substrate radical. This enzymatic solution to an unsolved chemical challenge is potentially generalizable to installation of other functional groups, provided that the corresponding anions can support the four requisite steps. We show here that the wild-type halogenase SyrB2 can indeed direct aliphatic nitration and azidation reactions by the same chemical logic. The discovery and enhancement by mutagenesis of these previously unknown reaction types suggest unrecognized or untapped versatility in ferryl-mediated enzymatic C-H bond activation.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Related mechanistic logic of the Fe/αKG halogenases and hydroxylases.
Figure 2: LC/MS analysis demonstrating the new C-N coupling reactions catalyzed by SyrB2.
Figure 3: Binding of chloride, azide and nitrite to the SyrB2–Fe(II)–αKG complex monitored by perturbations to the absorption spectrum from the Fe(II)→αKG MLCT transition.
Figure 4: Triggering of O2 addition and ferryl formation in SyrB2 by binding of the anion.
Figure 5: Enhanced efficiency of C-N coupling in the A118G variant of SyrB2.

Similar content being viewed by others

References

  1. Godula, K. & Sames, D. C-H bond functionalization in complex organic synthesis. Science 312, 67–72 (2006).

    Article  CAS  Google Scholar 

  2. Herrerías, C.I., Yao, X., Li, Z. & Li, C.J. Reactions of C-H bonds in water. Chem. Rev. 107, 2546–2562 (2007).

    Article  Google Scholar 

  3. Solomon, E.I. et al. Geometric and electronic structure/function correlations in non-heme iron enzymes. Chem. Rev. 100, 235–350 (2000).

    Article  CAS  Google Scholar 

  4. Costas, M., Mehn, M.P., Jensen, M.P. & Que, L. Jr. Dioxygen activation at mononuclear nonheme iron active sites: enzymes, models, and intermediates. Chem. Rev. 104, 939–986 (2004).

    Article  CAS  Google Scholar 

  5. Krebs, C., Galonić Fujimori, D., Walsh, C.T. & Bollinger, J.M. Jr. Non-heme Fe(IV)-oxo intermediates. Acc. Chem. Res. 40, 484–492 (2007).

    Article  CAS  Google Scholar 

  6. Booker, S.J. Anaerobic functionalization of unactivated C-H bonds. Curr. Opin. Chem. Biol. 13, 58–73 (2009).

    Article  CAS  Google Scholar 

  7. Bollinger, J.M. Jr. & Broderick, J.B. Frontiers in enzymatic C-H-bond activation. Curr. Opin. Chem. Biol. 13, 51–57 (2009).

    Article  CAS  Google Scholar 

  8. van der Donk, W.A., Krebs, C. & Bollinger, J.M. Jr. Substrate activation by iron superoxo intermediates. Curr. Opin. Struct. Biol. 20, 673–683 (2010).

    Article  CAS  Google Scholar 

  9. Lewis, J.C., Coelho, P.S. & Arnold, F.H. Enzymatic functionalization of carbon-hydrogen bonds. Chem. Soc. Rev. 40, 2003–2021 (2011).

    Article  CAS  Google Scholar 

  10. Sydor, P.K. et al. Regio- and stereodivergent antibiotic oxidative carbocyclizations catalysed by Rieske oxygenase-like enzymes. Nat. Chem. 3, 388–392 (2011).

    Article  CAS  Google Scholar 

  11. Hausinger, R.P. Fe(ii)/α-ketoglutarate–dependent hydroxylases and related enzymes. Crit. Rev. Biochem. Mol. Biol. 39, 21–68 (2004).

    Article  CAS  Google Scholar 

  12. Ogura, K. & Sankawa, U. Dynamic Aspects of Natural Products Chemistry (Kodansha Ltd. and Harwood Academic Publishers, 1997).

  13. Baldwin, J.E. & Bradley, M. Isopenicillin N synthase: mechanistic studies. Chem. Rev. 90, 1079–1088 (1990).

    Article  CAS  Google Scholar 

  14. Vaillancourt, F.H., Yeh, E., Vosburg, D.A., Garneau-Tsodikova, S. & Walsh, C.T. Nature's inventory of halogenation catalysts: oxidative strategies predominate. Chem. Rev. 106, 3364–3378 (2006).

    Article  CAS  Google Scholar 

  15. Galonić, D.P., Barr, E.W., Walsh, C.T., Bollinger, J.M. Jr. & Krebs, C. Two interconverting Fe(IV) intermediates in aliphatic chlorination by the halogenase CytC3. Nat. Chem. Biol. 3, 113–116 (2007).

    Article  Google Scholar 

  16. Matthews, M.L. et al. Substrate-triggered formation and remarkable stability of the C-H bond-cleaving chloroferryl intermediate in the aliphatic halogenase, SyrB2. Biochemistry 48, 4331–4343 (2009).

    Article  CAS  Google Scholar 

  17. McIntosh, J.A. et al. Enantioselective intramolecular C-H amination catalyzed by engineered cytochrome P450 enzymes in vitro and in vivo. Angew. Chem. Int. Ed. Engl. 52, 9309–9312 (2013).

    Article  CAS  Google Scholar 

  18. Surry, D.S. & Buchwald, S.L. Dialkylbiaryl phosphines in Pd-catalyzed amination: a user's guide. Chem. Sci. 2, 27–50 (2011).

    Article  CAS  Google Scholar 

  19. Cho, S.H., Kim, J.Y., Kwak, J. & Chang, S. Recent advances in the transition metal–catalyzed twofold oxidative C-H bond activation strategy for C-C and C-N bond formation. Chem. Soc. Rev. 40, 5068–5083 (2011).

    Article  CAS  Google Scholar 

  20. Price, J.C., Barr, E.W., Hoffart, L.M., Krebs, C. & Bollinger, J.M. Jr. Kinetic dissection of the catalytic mechanism of taurine: α-ketoglutarate dioxygenase (TauD) from Escherichia coli. Biochemistry 44, 8138–8147 (2005).

    Article  CAS  Google Scholar 

  21. Groves, J.T. Key elements of the chemistry of cytochrome P-450. The oxygen rebound mechanism. J. Chem. Educ. 62, 928–931 (1985).

    Article  CAS  Google Scholar 

  22. Blasiak, L.C., Vaillancourt, F.H., Walsh, C.T. & Drennan, C.L. Crystal structure of the non-haem iron halogenase SyrB2 in syringomycin biosynthesis. Nature 440, 368–371 (2006).

    Article  CAS  Google Scholar 

  23. Fujimori, D.G. et al. Spectroscopic evidence for a high-spin Br-Fe(IV)-oxo intermediate in the α-ketoglutarate–dependent halogenase CytC3 from Streptomyces. J. Am. Chem. Soc. 129, 13408–13409 (2007).

    Article  CAS  Google Scholar 

  24. Matthews, M.L. et al. Substrate positioning controls the partition between halogenation and hydroxylation in the aliphatic halogenase, SyrB2. Proc. Natl. Acad. Sci. USA 106, 17723–17728 (2009).

    Article  CAS  Google Scholar 

  25. Vaillancourt, F.H., Yin, J. & Walsh, C.T. SyrB2 in syringomycin E biosynthesis is a nonheme Fe(ii) α-ketoglutarate– and O2-dependent halogenase. Proc. Natl. Acad. Sci. USA 102, 10111–10116 (2005).

    Article  CAS  Google Scholar 

  26. Vaillancourt, F.H., Vosburg, D.A. & Walsh, C.T. Dichlorination and bromination of a threonyl-S-carrier protein by the non-heme Fe(II) halogenase SyrB2. ChemBioChem 7, 748–752 (2006).

    Article  CAS  Google Scholar 

  27. Kulik, H.J. & Drennan, C.L. Substrate placement influences reactivity in non-heme Fe(II) halogenases and hydroxylases. J. Biol. Chem. 288, 11233–11241 (2013).

    Article  CAS  Google Scholar 

  28. Ye, S. & Neese, F. Nonheme oxo-iron(IV) intermediates form an oxyl radical upon approaching the C-H bond activation transition state. Proc. Natl. Acad. Sci. USA 108, 1228–1233 (2011).

    Article  CAS  Google Scholar 

  29. Wong, S.D. et al. Elucidation of the Fe(iv)=O intermediate in the catalytic cycle of the halogenase SyrB2. Nature 499, 320–323 (2013).

    Article  CAS  Google Scholar 

  30. Neidig, M.L. et al. CD and MCD of CytC3 and taurine dioxygenase: role of the facial triad in α-KG–dependent oxygenases. J. Am. Chem. Soc. 129, 14224–14231 (2007).

    Article  CAS  Google Scholar 

  31. Strickler, S.J. & Kasha, M. Solvent effects on the electronic absorption spectrum of nitrite ion. J. Am. Chem. Soc. 85, 2899–2901 (1963).

    Article  CAS  Google Scholar 

  32. Huisgen, R. 1,3-Dipolar Cycloaddition Chemistry 1–176 (Wiley, New York, 1984).

  33. Saxon, E. & Bertozzi, C.R. Cell surface engineering by a modified Staudinger reaction. Science 287, 2007–2010 (2000).

    Article  CAS  Google Scholar 

  34. Kolb, H.C., Finn, M.G. & Sharpless, K.B. Click chemistry: diverse chemical function from a few good reactions. Angew. Chem. Int. Ed. Engl. 40, 2004–2021 (2001).

    Article  CAS  Google Scholar 

  35. Fraústo da Silva, J.J.R. & Williams, R.J.P. The Biological Chemistry of the Elements: the Inorganic Chemistry of Life 2nd edn. (Oxford University Press, USA, 2001).

  36. Barry, S.M. et al. Cytochrome P450-catalyzed l-tryptophan nitration in thaxtomin phytotoxin biosynthesis. Nat. Chem. Biol. 8, 814–816 (2012).

    Article  CAS  Google Scholar 

  37. Hyster, T.K., Knorr, L., Ward, T.R. & Rovis, T. Biotinylated Rh(III) complexes in engineered streptavidin for accelerated asymmetric C-H activation. Science 338, 500–503 (2012).

    Article  CAS  Google Scholar 

  38. Wang, Z., Zhang, Y., Fu, H., Jiang, Y. & Zhao, Y. Efficient intermolecular iron-catalyzed amidation of C-H bonds in the presence of N-bromosuccinimide. Org. Lett. 10, 1863–1866 (2008).

    Article  CAS  Google Scholar 

  39. Paradine, S.M. & White, M.C. Iron-catalyzed intramolecular allylic C-H amination. J. Am. Chem. Soc. 134, 2036–2039 (2012).

    Article  CAS  Google Scholar 

  40. Nguyen, Q., Nguyen, T. & Driver, T.G. Iron(ii) bromide–catalyzed intramolecular C-H bond amination [1,2]-shift tandem reactions of aryl azides. J. Am. Chem. Soc. 135, 620–623 (2013).

    Article  CAS  Google Scholar 

  41. Hennessy, E.T. & Betley, T.A. Complex N-heterocycle synthesis via iron-catalyzed, direct C-H bond amination. Science 340, 591–595 (2013).

    Article  CAS  Google Scholar 

  42. Stevens, B.W., Lilien, R.H., Georgiev, I., Donald, B.R. & Anderson, A.C. Redesigning the PheA domain of gramicidin synthetase leads to a new understanding of the enzyme's mechanism and selectivity. Biochemistry 45, 15495–15504 (2006).

    Article  CAS  Google Scholar 

  43. Han, J.W. et al. Site-directed modification of the adenylation domain of the fusaricidin nonribosomal peptide synthetase for enhanced production of fusaricidin analogs. Biotechnol. Lett. 34, 1327–1334 (2012).

    Article  CAS  Google Scholar 

  44. Savile, C.K. et al. Biocatalytic asymmetric synthesis of chiral amines from ketones applied to sitagliptin manufacture. Science 329, 305–309 (2010).

    Article  CAS  Google Scholar 

  45. Huisman, G.W. & Collier, S.J. On the development of new biocatalytic processes for practical pharmaceutical synthesis. Curr. Opin. Chem. Biol. 17, 284–292 (2013).

    Article  CAS  Google Scholar 

  46. Cashin, A.L., Torrice, M.M., McMenimen, K.A., Lester, H.A. & Dougherty, D.A. Chemical-scale studies on the role of a conserved aspartate in preorganizing the agonist binding site of the nicotinic acetylcholine receptor. Biochemistry 46, 630–639 (2007).

    Article  CAS  Google Scholar 

  47. Price, J.C., Barr, E.W., Tirupati, B., Bollinger, J.M. Jr. & Krebs, C. The first direct characterization of a high-valent iron intermediate in the reaction of an α-ketoglutarate-dependent dioxygenase: a high-spin Fe(IV) complex in taurine/α-ketoglutarate dioxygenase (TauD) from Escherichia coli. Biochemistry 42, 7497–7508 (2003).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

This work was supported by the National Institutes of Health (GM-69657 to C.K. and J.M.B. Jr.) and the National Science Foundation (MCB-642058 and CHE-724084 to C.K. and J.M.B. Jr.). We thank C. Drennan and M. Dey at the Massachusetts Institute of Technology for the kind gift of the plasmid to express SyrB2A118G.

Author information

Authors and Affiliations

Authors

Contributions

M.L.M. prepared reagents, designed and carried out experiments, analyzed data and composed and edited the manuscript. W-c.C. prepared reagents, designed and carried out experiments, analyzed data and edited the manuscript. A.P.L. prepared reagents, carried out experiments and analyzed data. L.A.M. prepared reagents, carried out experiments and analyzed data. C.K. designed experiments, analyzed data and edited the manuscript. J.M.B. Jr. designed experiments and composed and edited the manuscript.

Corresponding authors

Correspondence to Megan L Matthews or J Martin Bollinger Jr.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Text and Figures

Supplementary Results, Supplementary Tables 1–4 and Supplementary Figures 1–13. (PDF 4989 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Matthews, M., Chang, Wc., Layne, A. et al. Direct nitration and azidation of aliphatic carbons by an iron-dependent halogenase. Nat Chem Biol 10, 209–215 (2014). https://doi.org/10.1038/nchembio.1438

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nchembio.1438

This article is cited by

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing