9 publications

9 publications

A Designed Heme-[4Fe-4S] Metalloenzyme Catalyzes Sulfite Reduction like the Native Enzyme

Lu, Y.

Science, 2018, 10.1126/science.aat8474

Multielectron redox reactions often require multicofactor metalloenzymes to facilitate coupled electron and proton movement, but it is challenging to design artificial enzymes to catalyze these important reactions, owing to their structural and functional complexity. We report a designed heteronuclear heme-[4Fe-4S] cofactor in cytochrome c peroxidase as a structural and functional model of the enzyme sulfite reductase. The initial model exhibits spectroscopic and ligand-binding properties of the native enzyme, and sulfite reduction activity was improved—through rational tuning of the secondary sphere interactions around the [4Fe-4S] and the substrate-binding sites—to be close to that of the native enzyme. By offering insight into the requirements for a demanding six-electron, seven-proton reaction that has so far eluded synthetic catalysts, this study provides strategies for designing highly functional multicofactor artificial enzymes.


Metal: Fe
Host protein: Cytochrome c peroxidase
Anchoring strategy: Dative
Optimization: Chemical & genetic
Reaction: Sulfite reduction
Max TON: ---
ee: ---
PDB: ---
Notes: Designed heteronuclear heme-[4Fe-4S] cofactor in cytochrome c peroxidase

A Designed Supramolecular Protein Assembly with In Vivo Enzymatic Activity

Tezcan, F. A.

Science, 2014, 10.1126/science.1259680

The generation of new enzymatic activities has mainly relied on repurposing the interiors of preexisting protein folds because of the challenge in designing functional, three-dimensional protein structures from first principles. Here we report an artificial metallo-β-lactamase, constructed via the self-assembly of a structurally and functionally unrelated, monomeric redox protein into a tetrameric assembly that possesses catalytic zinc sites in its interfaces. The designed metallo-β-lactamase is functional in the Escherichia coli periplasm and enables the bacteria to survive treatment with ampicillin. In vivo screening of libraries has yielded a variant that displays a catalytic proficiency [(kcat/Km)/kuncat] for ampicillin hydrolysis of 2.3 × 106 and features the emergence of a highly mobile loop near the active site, a key component of natural β-lactamases to enable substrate interactions.


Metal: Zn
Ligand type: Amino acid
Host protein: Cytochrome cb562
Anchoring strategy: Dative
Optimization: Genetic
Max TON: ---
ee: ---
PDB: 4U9E
Notes: ---

An Artificial Metalloenzyme with the Kinetics of Native Enzymes

Hartwig, J. F.

Science, 2016, 10.1126/science.aah4427

Natural enzymes contain highly evolved active sites that lead to fast rates and high selectivities. Although artificial metalloenzymes have been developed that catalyze abiological transformations with high stereoselectivity, the activities of these artificial enzymes are much lower than those of natural enzymes. Here, we report a reconstituted artificial metalloenzyme containing an iridium porphyrin that exhibits kinetic parameters similar to those of natural enzymes. In particular, variants of the P450 enzyme CYP119 containing iridium in place of iron catalyze insertions of carbenes into C–H bonds with up to 98% enantiomeric excess, 35,000 turnovers, and 2550 hours−1 turnover frequency. This activity leads to intramolecular carbene insertions into unactivated C–H bonds and intermolecular carbene insertions into C–H bonds. These results lift the restrictions on merging chemical catalysis and biocatalysis to create highly active, productive, and selective metalloenzymes for abiological reactions.


Metal: Ir
Ligand type: Methyl; Porphyrin
Host protein: Cytochrome P450 (CYP119)
Anchoring strategy: Metal substitution
Optimization: Chemical & genetic
Reaction: C-H activation
Max TON: 582
ee: 98
PDB: ---
Notes: ---

Metal: Ir
Ligand type: Methyl; Porphyrin
Host protein: Cytochrome P450 (CYP119)
Anchoring strategy: Metal substitution
Optimization: Chemical & genetic
Reaction: C-H activation
Max TON: 35129
ee: 91
PDB: ---
Notes: ---

Biotinylated Rh(III) Complexes in Engineered Streptavidin for Accelerated Asymmetric C–H Activation

Rovis, T.; Ward, T. R.

Science, 2012, 10.1126/science.1226132


Metal: Rh
Ligand type: Amino acid; Cp*
Host protein: Streptavidin (Sav)
Anchoring strategy: Supramolecular
Optimization: Genetic
Reaction: C-H activation
Max TON: 95
ee: 82
PDB: ---
Notes: ---

Chemical Conversion of a DNA-Binding Protein into a Site-Specific Nuclease

Sigman, D. S.

Science, 1987, 10.1126/science.2820056


Metal: Cu
Ligand type: Phenanthroline
Anchoring strategy: Covalent
Optimization: ---
Reaction: Oxidative cleavage
Max TON: <1
ee: ---
PDB: ---
Notes: Engineered sequence specificity

Design and Evolution of New Catalytic Activity with an Existing Protein Scaffold

Kim, H. S.

Science, 2006, 10.1126/science.1118953


Metal: Zn
Ligand type: Amino acid
Host protein: Glyoxalase II (Human)
Anchoring strategy: Dative
Optimization: Genetic
Max TON: ---
ee: ---
PDB: 2F50
Notes: kcat/KM ≈ 184 M-1*s-1

Generation of a Hybrid Sequence-Specific Single Stranded Deoxyribonuclease

Schultz, P. G.

Science, 1987, 10.1126/science.3685986


Metal: Ca
Ligand type: Undefined
Host protein: Staphylococcal nuclease
Anchoring strategy: ---
Optimization: ---
Max TON: <1
ee: ---
PDB: ---
Notes: Engineered sequence specificity

Sequence-Specific Peptide Cleavage Catalyzed by an Antibody

Lerner, R. A.

Science, 1989, 10.1126/science.2922606


Metal: Zn
Ligand type: Tetramine
Host protein: Antibody 28F11
Anchoring strategy: Supramolecular
Optimization: Chemical
Max TON: 400
ee: ---
PDB: ---
Notes: ---

Synthesis of a Sequence-Specific DNA-Cleaving Peptide

Dervan, P. B.

Science, 1987, 10.1126/science.3120311


Metal: Fe
Ligand type: EDTA
Anchoring strategy: Covalent
Optimization: ---
Reaction: DNA cleavage
Max TON: <1
ee: ---
PDB: ---
Notes: Engineered sequence specificity