6 publications

6 publications

Addressable DNA–Myoglobin Photocatalysis

Niemeyer, C.M.

Chem. - Asian J. 2009, 4, 1064-1069, 10.1002/asia.200900082

A hybrid myoglobin, containing a single‐stranded DNA anchor and a redox‐active ruthenium moiety tethered to the heme center can be used as a photocatalyst. The catalyst can be selectively immobilized on a surface‐bound complementary DNA molecule and thus readily recycled from complex reaction mixtures. This principle may be applied to a range of heme‐dependent enzymes allowing the generation of novel light‐triggered photocatalysts. Photoactivatable myoglobin containing a DNA oligonucleotide as a structural anchor was designed by using the reconstitution of artificial heme moieties containing Ru3+ ions. This semisynthetic DNA–enzyme conjugate was successfully used for the oxidation of peroxidase substrates by using visible light instead of H2O2 for the activation. The DNA anchor was utilized for the immobilization of the enzyme on the surface of magnetic microbeads. Enzyme activity measurements not only indicated undisturbed biofunctionality of the tethered DNA but also enabled magnetic separation‐based enrichment and recycling of the photoactivatable biocatalyst.


Metal: Ru
Ligand type: Bipyridine
Host protein: Myoglobin (Mb)
Anchoring strategy: Supramolecular
Optimization: ---
Reaction: Photooxidation
Max TON: ---
ee: ---
PDB: ---
Notes: Horse heart myoglobin

Artificial Dicopper Oxidase: Rational Reprogramming of Bacterial Metallo- b-lactamase into a Catechol Oxidase

Fujieda, N.; Itoh, S.

Chem. - Asian J. 2012, 7, 1203-1207, 10.1002/asia.201101014

Teaching metalloenzymes new tricks: An artificial type III dicopper oxidase has been developed using a hydrolytic enzyme, metallo‐β‐lactamase, as a metal‐binding platform. The triple mutant D88G/S185H/P224G redesigned by computer‐assisted structural analysis showed spectroscopic features similar to those of type III copper proteins and exhibited a high catalytic activity in the oxidation of catechols under aerobic conditions.


Metal: Cu
Ligand type: Amino acid
Host protein: β-lactamase
Anchoring strategy: Dative
Optimization: Genetic
Reaction: Catechol oxidation
Max TON: ---
ee: ---
PDB: 2FU7
Notes: ---

Catalytic Water Oxidation by Iridium-Modified Carbonic Anhydrase

Lee, S.-Y.

Chem. - Asian J. 2018, 13, 334-341, 10.1002/asia.201701543

Carbonic anhydrase (CA) is a ubiquitous metalloenzyme with a Zn cofactor coordinated to trigonal histidine imidazole moieties in a tetrahedral geometry. Removal of the Zn cofactor in CA and subsequent binding of Ir afforded CA[Ir]. Under mild and neutral conditions (30 °C, pH 7), CA[Ir] exhibited water‐oxidizing activity with a turnover frequency (TOF) of 39.8 min−1, which is comparable to those of other Ir‐based molecular catalysts. Coordination of Ir to the apoprotein of CA is thermodynamically preferred and is associated with an exothermic energy change (ΔH) of −10.8 kcal mol−1, which implies that the CA apoprotein is stabilized by Ir binding. The catalytic oxygen‐evolving activity of CA[Ir] is displayed only if Ir is bound to CA, which functions as an effective biological scaffold that activates the Ir center for catalysis. The results of this study indicate that the histidine imidazoles at the CA active site could be exploited as beneficial biological ligands to provide unforeseen biochemical activity by coordination to a variety of transition‐metal ions.


Metal: Ir
Ligand type: Amino acid
Anchoring strategy: Metal substitution
Optimization: Chemical
Reaction: Water oxidation
Max TON: ---
ee: ---
PDB: ---
Notes: Sodium periodate as sacrificial oxidant. TOF at pH 7 and 30°C is 39.8 min-1.

Hybrid Ruthenium ROMP Catalysts Based on an Engineered Variant of β-Barrel Protein FhuA ΔCVFtev: Effect of Spacer Length

Okuda, J.

Chem. - Asian J. 2015, 10, 177-182, 10.1002/asia.201403005

A biohybrid ring‐opening olefin metathesis polymerization catalyst based on the reengineered β‐barrel protein FhuA ΔCVFtev was chemically modified with respect to the covalently anchored Grubbs–Hoveyda type catalyst. Shortening of the spacer (1,3‐propanediyl to methylene) between the N‐heterocyclic carbene ligand and the cysteine site 545 increased the ROMP activity toward a water‐soluble 7‐oxanorbornene derivative. The cis/trans ratio of the double bond in the polymer was influenced by the hybrid catalyst.


Metal: Ru
Ligand type: Carbene
Host protein: FhuA ΔCVFtev
Anchoring strategy: Covalent
Optimization: Chemical
Reaction: Olefin metathesis
Max TON: 555
ee: ---
PDB: ---
Notes: ROMP; cis/trans = 58/42

Porous Protein Crystals as Catalytic Vessels for Organometallic Complexes

Kitagawa, S.; Ueno, T.

Chem. - Asian J. 2014, 9, 1373-1378, 10.1002/asia.201301347

Porous protein crystals, which are protein assemblies in the solid state, have been engineered to form catalytic vessels by the incorporation of organometallic complexes. Ruthenium complexes in cross‐linked porous hen egg white lysozyme (HEWL) crystals catalyzed the enantioselective hydrogen‐transfer reduction of acetophenone derivatives. The crystals accelerated the catalytic reaction and gave different enantiomers based on the crystal form (tetragonal or orthorhombic). This method represents a new approach for the construction of bioinorganic catalysts from protein crystals.


Metal: Ru
Ligand type: Benzene
Host protein: Lysozyme (crystal)
Anchoring strategy: Dative
Optimization: ---
Max TON: ---
ee: ---
PDB: 3W6A
Notes: Tetragonal HEWL crystals

Metal: Ru
Ligand type: Benzene
Host protein: Lysozyme (crystal)
Anchoring strategy: Dative
Optimization: ---
Max TON: ---
ee: ---
PDB: 4J7V
Notes: Orthorhombic HEWL crystals

Precise Design of Artificial Cofactors for Enhancing Peroxidase Activity of Myoglobin: Myoglobin Mutant H64D Reconstituted with a “Single-Winged Cofactor” is Equivalent to Native Horseradish Peroxidase in Oxidation Activity

Matsuo, T.

Chem. - Asian J. 2011, 6, 2491-2499, 10.1002/asia.201100107

H64D myoglobin mutant was reconstituted with two different types of synthetic hemes that have aromatic rings and a carboxylate‐based cluster attached to the terminus of one or both of the heme‐propionate moieties, thereby forming a “single‐winged cofactor” and “double‐winged cofactor,” respectively. The reconstituted mutant myoglobins have smaller Km values with respect to 2‐methoxyphenol oxidation activity relative to the parent mutant with native heme. This suggests that the attached moiety functions as a substrate‐binding domain. However, the kcat value of the mutant myoglobin with the double‐winged cofactor is much lower than that of the mutant with the native heme. In contrast, the mutant reconstituted with the single‐winged cofactor has a larger kcat value, thereby resulting in overall catalytic activity that is essentially equivalent to that of the native horseradish peroxidase. Enhanced peroxygenase activity was also observed for the mutant myoglobin with the single‐winged cofactor, thus indicating that introduction of an artificial substrate‐binding domain at only one of the heme propionates in the H64D mutant is the optimal engineering strategy for improving the peroxidase activity of myoglobin.


Metal: Fe
Host protein: Myoglobin (Mb)
Anchoring strategy: Reconstitution
Optimization: Chemical & genetic
Max TON: ---
ee: ---
PDB: ---
Notes: ---