3 publications

3 publications

A Cell-Penetrating Artificial Metalloenzyme Regulates a Gene Switch in a Designer Mammalian Cell

Fussenegger, M.; Matile, S.; Ward, T.R.

Nat. Commun. 2018, 9, 10.1038/s41467-018-04440-0

Complementing enzymes in their native environment with either homogeneous or heterogeneous catalysts is challenging due to the sea of functionalities present within a cell. To supplement these efforts, artificial metalloenzymes are drawing attention as they combine attractive features of both homogeneous catalysts and enzymes. Herein we show that such hybrid catalysts consisting of a metal cofactor, a cell-penetrating module, and a protein scaffold are taken up into HEK-293T cells where they catalyze the uncaging of a hormone. This bioorthogonal reaction causes the upregulation of a gene circuit, which in turn leads to the expression of a nanoluc-luciferase. Relying on the biotin–streptavidin technology, variation of the biotinylated ruthenium complex: the biotinylated cell-penetrating poly(disulfide) ratio can be combined with point mutations on streptavidin to optimize the catalytic uncaging of an allyl-carbamate-protected thyroid hormone triiodothyronine. These results demonstrate that artificial metalloenzymes offer highly modular tools to perform bioorthogonal catalysis in live HEK cells.


Metal: Ru
Ligand type: Cp; Quinoline
Host protein: Streptavidin (Sav)
Anchoring strategy: Supramolecular
Optimization: Genetic
Reaction: Deallylation
Max TON: 33
ee: ---
PDB: ---
Notes: ---

Construction and In Vivo Assembly of a Catalytically Proficient and Hyperthermostable De Novo Enzyme

Anderson, J.L.R.

Nat. Commun. 2017, 8, 10.1038/s41467-017-00541-4

Although catalytic mechanisms in natural enzymes are well understood, achieving the diverse palette of reaction chemistries in re-engineered native proteins has proved challenging. Wholesale modification of natural enzymes is potentially compromised by their intrinsic complexity, which often obscures the underlying principles governing biocatalytic efficiency. The maquette approach can circumvent this complexity by combining a robust de novo designed chassis with a design process that avoids atomistic mimicry of natural proteins. Here, we apply this method to the construction of a highly efficient, promiscuous, and thermostable artificial enzyme that catalyzes a diverse array of substrate oxidations coupled to the reduction of H2O2. The maquette exhibits kinetics that match and even surpass those of certain natural peroxidases, retains its activity at elevated temperature and in the presence of organic solvents, and provides a simple platform for interrogating catalytic intermediates common to natural heme-containing enzymes.


Metal: Fe
Ligand type: Porphyrin
Anchoring strategy: Supramolecular
Optimization: Genetic
Reaction: Oxidation
Max TON: ---
ee: ---
PDB: ---
Notes: Oxidation of 2,2′-azino-bis(3-ethylbenzothiazo-line-6-sulfonic acid (ABTS)

Engineering a Dirhodium Artificial Metalloenzyme for Selective Olefin Cyclopropanation

Lewis, J.C.

Nat. Commun. 2015, 6, 10.1038/ncomms8789

Artificial metalloenzymes (ArMs) formed by incorporating synthetic metal catalysts into protein scaffolds have the potential to impart to chemical reactions selectivity that would be difficult to achieve using metal catalysts alone. In this work, we covalently link an alkyne-substituted dirhodium catalyst to a prolyl oligopeptidase containing a genetically encoded L-4-azidophenylalanine residue to create an ArM that catalyses olefin cyclopropanation. Scaffold mutagenesis is then used to improve the enantioselectivity of this reaction, and cyclopropanation of a range of styrenes and donor–acceptor carbene precursors were accepted. The ArM reduces the formation of byproducts, including those resulting from the reaction of dirhodium–carbene intermediates with water. This shows that an ArM can improve the substrate specificity of a catalyst and, for the first time, the water tolerance of a metal-catalysed reaction. Given the diversity of reactions catalysed by dirhodium complexes, we anticipate that dirhodium ArMs will provide many unique opportunities for selective catalysis.


Metal: Rh
Ligand type: Poly-carboxylic acid
Anchoring strategy: Covalent
Optimization: Chemical & genetic
Reaction: Cyclopropanation
Max TON: 74
ee: 92
PDB: ---
Notes: ---