Merging organometallic chemistry with biotechnology

Artificial Metalloenzymes

Organometallic- and enzymatic catalysis have evolved independently over the past four decades. In many respects, these approaches can be viewed as complementary. By incorporating an organometallic moiety within a protein host, we create artificial metallo-enzymes, with properties reminiscent both of homogeneous and enzymatic catalysis. The main focus of our research is to exploit such hybrid systems towards various applications.

  • Enantioselective catalysis (white biotechnology)
  • Synthetic biology (metabolic engineering)
  • Bio-nanotechnology

In order to ensure unambiguous localisation of the organometallic moiety within the host protein, we rely on various anchoring strategies.

  • Covalent anchoring exploiting carbonic anhydrase as scaffold
  • Supramolecular anchoring exploiting the biotin-streptavidin couple
  • Dative anchoring upon repurposing proteins with latent facial triad motifs

X-ray structure of an artificial metalloenzyme based on the biotin-streptavidin technology

Basic Concept

In the spirit of E. Fischer's Lock and Key. The anchor (for example biotin) displays a very high affinity for the host protein (for example streptavidin (Ka 1014 M–1)). A catalytically competent organometallic moiety, linked via a spacer to biotin is combined with streptavidin to yield an artificial metalloenzyme. A broadly applicable chemogenetic optimization strategy relies on
i) mutations (*) on streptavidin and
ii) variation of the spacer and the bidentate ligand
This strategy can be applied to any host protein-cofactor couple

The chemogenetic optimisation strategy combines random mutagenesis (the rows) of the host protein with chemical variation of the anchored cofactor (the columns). After screening various spacers and ligands, a directed evolution protocol allows to screen thousands of mutants with the selected cofactor to identify versatile artificial metalloenzymes

A Mosaic of Applications
Reactions Implemented

Acc. Chem. Res., 2016, 49, 1711.
Acc. Chem. Res., 2011, 44, 47.

Selected recent publications
  • Directed evolution of artificial metalloenzymes for in vivo metathesis

    M. Jeschek, R. Reuter, T. Heinisch, C. Trindler, J. Klehr, S. Panke, T. R. Ward

    Nature, 2016, 537, 661. 10.1038/nature19114

  • An NAD(P)H-dependent Artificial Transfer Hydrogenase for Multi-enzymatic Cascades

    Y. Okamoto, V. Köhler, T. R. Ward

    J. Am. Chem. Soc., 2016, 138, 5781. 10.1021/jacs.6b02470

  • Anion-π Enzymes

    Y. Cotelle, V. Lebrun, N. Sakai, T. R. Ward, S. Matile

    ACS Cent. Sci., 2016, 2, 388. 10.1021/acscentsci.6b00097

  • Artificial Metalloenzymes Based on the Biotin–Streptavidin Technology: Challenges and Opportunities

    T. Heinisch, T. R. Ward

    Acc. Chem. Res., 2016, 49, 1711. 10.1021/acs.accounts.6b00235

  • Library design and screening protocol for artificial metalloenzymes based on the biotin-streptavidin technology

    H. Mallin, M. Hestericová, R. Reuter, T. R. Ward

    Nat. Protoc., 2016, 11, 835. 10.1038/nprot.2016.019

  • Improving the Catalytic Performance of an Artificial Metalloenzyme by Computational Design

    T. Heinisch, M. Pellizzoni, M. Dürrenberger, C. E. Tinberg, V. Köhler, J. Klehr, T. Schirmer, D. Baker and T. R. Ward

    J. Am. Chem. Soc., 2015, 137, 10414. 10.1021/jacs.5b06622

  • Neutralizing the Detrimental Effect of Glutathione on Precious Metal Catalysts

    Y. M. Wilson, M. Dürrenberger, E. Nogueira, T. R. Ward

    J. Am. Chem. Soc., 2014, 136, 8928. 10.1021/ja500613n

  • Human Carbonic Anhydrase II as Host Protein for the Creation of Artificial Metalloenzymes: The Asymmetric Transfer Hydrogenation of Imines

    F. Monnard, E. Nogueira, T. Heinisch, T. Schirmer, T. R. Ward

    Chem. Sci., 2013, 4, 3269. 10.1039/c3sc51065d

  • New Synthetic Cascades by Combining Biocatalysts with Artificial Metalloenzymes

    V. Köhler, Y. M. Wilson, M. Dürrenberger, D. Ghislieri, E. Churakova, T. Quinto, L. Knörr, D. Häussinger, F. Hollmann, N. J. Turner, T. R. Ward

    Nat. Chem., 2013, 5, 93. 10.1038/nchem.1498

  • Biotinylated Rh(III) Complexes in Engineered Streptavidin for Rate Enhanced Asymmetric C-H Activation

    T. K. Hyster, L. Knörr, T. R. Ward, T. Rovis

    Science, 2012, 338, 500. 10.1126/science.1226132