29 publications
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Achiral Cyclopentadienone Iron Tricarbonyl Complexes Embedded in Streptavidin: An Access to Artificial Iron Hydrogenases and Application in Asymmetric Hydrogenation
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Catal. Lett. 2016, 146, 564-569, 10.1007/s10562-015-1681-6
We report on the synthesis of biotinylated (cyclopentadienone)iron tricarbonyl complexes, the in situ generation of the corresponding streptavidin conjugates and their application in asymmetric hydrogenation of imines and ketones.
Metal: FeHost protein: Streptavidin (Sav)Anchoring strategy: SupramolecularOptimization: ChemicalNotes: ---
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An asymmetric catalyst
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Nature 1956, 178, 323-324, 10.1038/178323b0
Asymmetric synthesis has hitherto succeeded only by using reagents or solvents having the asymmetric configuration.
Metal: PdLigand type: UndefinedHost protein: Silk fibroin fibreAnchoring strategy: UndefinedOptimization: ---Notes: ---
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A Positive Charge in the Outer Coordination Sphere of an Artificial Enzyme Increases CO2 Hydrogenation
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Organometallics 2020, 39, 1532-1544, 10.1021/acs.organomet.9b00843
The protein scaffold around the active site of enzymes is known to influence catalytic activity, but specific scaffold features responsible for favorable influences are often not known. This study focuses on using an artificial metalloenzyme to probe one specific feature of the scaffold, the position of a positive charge in the outer coordination sphere around the active site. Previous work showed that a small molecular complex, [Rh(PEt2NglycinePEt2)2]−, immobilized covalently within a protein scaffold was activated for CO2 hydrogenation. Here, using an iterative design where the effect of arginine, histidine, or lysine residues placed in the outer coordination sphere of the catalytic active site were evaluated, we tested the hypothesis that positively charged groups facilitate CO2 hydrogenation with seven unique constructs. Single-, double-, and triple-point mutations were introduced to directly compare catalytic activity, as monitored by turnover frequencies (TOFs) measured in real time with 1H NMR spectroscopy, and evaluate related structural and electronic properties. Two of the seven constructs showed a 2- and 3-fold increase relative to the wild type, with overall rates ranging from 0.2 to 0.7 h–1, and a crystal structure of the fastest of these shows the positive charge positioned next to the active site. A crystal structure of the arginine-containing complex shows that the arginines are positioned near the metal. Molecular dynamics (MD) studies also suggest that the positive charge is oriented next to the active site in the two constructs with faster rates but not in the others and that the positive charge near the active site holds the CO2 near the metal, all consistent with a positive charge appropriately positioned in the scaffold benefiting catalysis. The MD studies also suggest that changes in the water distribution around the active site may contribute to catalytic activity, while modest structural changes and movement of the complex within the scaffold do not.
Metal: RhLigand type: BisdiphosphineHost protein: Lactoccal multidrug resistant regulator (LmrR)Anchoring strategy: CovalentOptimization: Chemical & computational designNotes: ---
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Aqueous Phase Transfer Hydrogenation of Aryl Ketones Catalysed by Achiral Ruthenium(II) and Rhodium(III) Complexes and their Papain Conjugates
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Appl. Organomet. Chem. 2013, 27, 6-12, 10.1002/aoc.2929
Several ruthenium and rhodium complexes including 2,2′‐dipyridylamine ligands substituted at the central N atom by an alkyl chain terminated by a maleimide functional group were tested along with a newly synthesized Rh(III) complex of unsubstituted 2,2′‐dipyridylamine as catalysts in the transfer hydrogenation of aryl ketones in neat water with formate as hydrogen donor. All of them except one led to the secondary alcohol products with conversion rates depending on the metal complex. Site‐specific anchoring of the N‐maleimide complexes to the single free cysteine residue of the cysteine endoproteinase papain endowed this protein with transfer hydrogenase properties towards 2,2,2‐trifluoroacetophenone. Quantitative conversions were reached with the Rh‐based biocatalysts, while modest enantioselectivities were obtained in certain reactional conditions.
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Artificial Metalloenzymes Derived from Bovine β-Lactoglobulin for the Asymmetric Transfer Hydrogenation of an Aryl Ketone – Synthesis, Characterization and Catalytic Activity
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Dalton Trans. 2014, 43, 5482-5489, 10.1039/c3dt53253d
Protein hybrids resulting from the supramolecular anchoring to bovine β-lactoglobulin of fatty acid-derived Rh(iii) diimine complexes catalysed the asymmetric transfer hydrogenation of trifluoroacetophenone with up to 32% ee.
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Artificial Metalloenzymes for Enantioselective Catalysis Based on Biotin-Avidin
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J. Am. Chem. Soc. 2003, 125, 9030-9031, 10.1021/ja035545i
Homogeneous and enzymatic catalysis offer complementary means to generate enantiomerically pure compounds. Incorporation of achiral biotinylated rhodium−diphosphine complexes into (strept)avidin yields artificial metalloenzymes for the hydrogenation of N-protected dehydroamino acids. A chemogenetic optimization procedure allows one to produce (R)-acetamidoalanine with 96% enantioselectivity. These hybrid catalysts display features reminiscent both of enzymatic and of homogeneous systems.
Metal: RhLigand type: PhosphineHost protein: Streptavidin (Sav)Anchoring strategy: SupramolecularOptimization: Chemical & geneticNotes: ---
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Artificial Metalloenzymes for Enantioselective Catalysis: The Phenomenon of Protein Accelerated Catalysis
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J. Organomet. Chem. 2004, 689, 4868-4871, 10.1016/j.jorganchem.2004.09.032
We report on the phenomenon of protein-accelerated catalysis in the field of artificial metalloenzymes based on the non-covalent incorporation of biotinylated rhodium–diphosphine complexes in (strept)avidin as host proteins. By incrementally varying the [Rh(COD)(Biot-1)]+ vs. (strept)avidin ratio, we show that the enantiomeric excess of the produced acetamidoalanine decreases slowly. This suggests that the catalyst inside (strept)avidin is more active than the catalyst outside the host protein. Both avidin and streptavidin display protein-accelerated catalysis as the protein embedded catalyst display 12.0- and 3.0-fold acceleration over the background reaction with a catalyst devoid of protein. Thus, these artificial metalloenzymes display an increase both in activity and in selectivity for the reduction of acetamidoacrylic acid.
Metal: RhHost protein: Streptavidin (Sav)Anchoring strategy: SupramolecularOptimization: ChemicalNotes: Reduction of acetamidoacrylic acid. 3.0-fold protein acceleration.
Notes: Reduction of acetamidoacrylic acid. 12.0-fold protein acceleration.
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Artificial Metalloenzymes: (Strept)avidin as Host for Enantioselective Hydrogenation by Achiral Biotinylated Rhodium-Diphosphine Complexes
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J. Am. Chem. Soc. 2004, 126, 14411-14418, 10.1021/ja0476718
We report on the generation of artificial metalloenzymes based on the noncovalent incorporation of biotinylated rhodium−diphosphine complexes in (strept)avidin as host proteins. A chemogenetic optimization procedure allows one to optimize the enantioselectivity for the reduction of acetamidoacrylic acid (up to 96% ee (R) in streptavidin S112G and up to 80% ee (S) in WT avidin). The association constant between a prototypical cationic biotinylated rhodium−diphosphine catalyst precursor and the host proteins was determined at neutral pH: log Ka = 7.7 for avidin (pI = 10.4) and log Ka = 7.1 for streptavidin (pI = 6.4). It is shown that the optimal operating conditions for the enantioselective reduction are 5 bar at 30 °C with a 1% catalyst loading.
Metal: RhLigand type: PhosphineHost protein: Streptavidin (Sav)Anchoring strategy: SupramolecularOptimization: Chemical & geneticNotes: ---
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Asymmetric Hydrogenation with Antibody-Achiral Rhodium Complex
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Org. Biomol. Chem. 2006, 4, 3571, 10.1039/B609242J
Monoclonal antibodies have been elicited against an achiral rhodium complex and this complex was used in the presence of a resultant antibody, 1G8, for the catalytic hydrogenation of 2-acetamidoacrylic acid to produce N-acetyl-L-alanine in high (>98%) enantiomeric excess.
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Burkavidin: A Novel Secreted Biotin-Binding Protein from the Human Pathogen Burkholderia Pseudomallei
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Protein Expression Purif. 2011, 77, 131-139, 10.1016/j.pep.2011.01.003
The avidin–biotin technology has many applications, including molecular detection; immobilization; protein purification; construction of supramolecular assemblies and artificial metalloenzymes. Here we present the recombinant expression of novel biotin-binding proteins from bacteria and the purification and characterization of a secreted burkavidin from the human pathogen Burkholderia pseudomallei. Expression of the native burkavidin in Escherichia coli led to periplasmic secretion and formation of a biotin-binding, thermostable, tetrameric protein containing an intra-monomeric disulphide bond. Burkavidin showed one main species as measured by isoelectric focusing, with lower isoelectric point (pI) than streptavidin. To exemplify the potential use of burkavidin in biotechnology, an artificial metalloenzyme was generated using this novel protein-scaffold and shown to exhibit enantioselectivity in a rhodium-catalysed hydrogenation reaction.
Metal: RhLigand type: DiphenylphosphineHost protein: BurkavidinAnchoring strategy: SupramolecularOptimization: Chemical & geneticNotes: ---
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Catalytic Hydrogenation of Itaconic Acid in a Biotinylated Pyrphos-Rhodium(I) System in a Protein Cavity
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Tetrahedron: Asymmetry 1999, 10, 1887-1893, 10.1016/S0957-4166(99)00193-7
The construction of a chiral catalyst system embedded at a specific site in a protein has been studied. The preparation of the biotinylated Pyrphos–Rh(I) complex attached to the binding site in avidin and its application to the asymmetric hydrogenation of itaconic acid have been investigated. By introducing the chiral Pyrphos–Rh(I) moiety into the constrained environment of the protein cavity it was found that the enantioselectivity of the system was significantly influenced by the tertiary conformation within the avidin cavity. The effects of reaction conditions such as temperature, hydrogen pressure, and the pH value of the buffer on enantioselectivity are reported.
Metal: RhLigand type: PhosphineHost protein: Avidin (Av)Anchoring strategy: SupramolecularOptimization: ---Notes: ---
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Chemically Engineered Papain as Artificial Formate Dehydrogenase for NAD(P)H Regeneration
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Org. Biomol. Chem. 2011, 9, 5720, 10.1039/c1ob05482a
Organometallic complexes of the general formula [(η6-arene)Ru(N⁁N)Cl]+ and [(η5-Cp*)Rh(N⁁N)Cl]+ where N⁁N is a 2,2′-dipyridylamine (DPA) derivative carrying a thiol-targeted maleimide group, 2,2′-bispyridyl (bpy), 1,10-phenanthroline (phen) or ethylenediamine (en) and arene is benzene, 2-chloro-N-[2-(phenyl)ethyl]acetamide or p-cymene were identified as catalysts for the stereoselective reduction of the enzyme cofactors NAD(P)+ into NAD(P)H with formate as a hydride donor. A thorough comparison of their effectiveness towards NAD+ (expressed as TOF) revealed that the RhIII complexes were much more potent catalysts than the RuII complexes. Within the RuII complex series, both the N⁁N and arene ligands forming the coordination sphere had a noticeable influence on the activity of the complexes. Covalent anchoring of the maleimide-functionalized RuII and RhIII complexes to the cysteine endoproteinase papain yielded hybrid metalloproteins, some of them displaying formate dehydrogenase activity with potentially interesting kinetic parameters.
Notes: TOF = 52.1 h-1 for NAD+
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Chemical Optimization of Artificial Metalloenzymes Based on the Biotin-Avidin Technology: (S)-Selective and Solvent-Tolerant Hydrogenation Catalysts via the Introduction of Chiral Amino Acid Spacers
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Chem. Commun. 2005, 4815, 10.1039/b509015f
Incorporation of biotinylated-[rhodium(diphosphine)]+ complexes, with enantiopure amino acid spacers, in streptavidin affords solvent-tolerant and selective artificial metalloenzymes: up to 91% ee (S) in the hydrogenation of N-protected dehydroamino acids.
Metal: RhLigand type: PhosphineHost protein: Streptavidin (Sav)Anchoring strategy: SupramolecularOptimization: ChemicalNotes: ---
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Conversion of a Protein to a Homogeneous Asymmetric Hydrogenation Catalyst by Site-Specific Modification with a Diphosphinerhodium (I) Moiety
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J. Am. Chem. Soc. 1978, 100, 306-307, 10.1021/ja00469a064
n/a
Metal: RhLigand type: PhosphineHost protein: Avidin (Av)Anchoring strategy: SupramolecularOptimization: ---Notes: ---
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Counter Propagation Artificial Neural Networks Modeling of an Enantioselectivity of Artificial Metalloenzymes
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Mol. Divers. 2007, 11, 141-152, 10.1007/s11030-008-9068-x
The counter propagation artificial neural networks (CP-ANNs) were used to develop a quantitative structure-selectivity relationship (QSSR) for a set of artificial metalloenzymes. The artificial metalloenzymes consist of biotinylated rhodium-diphosphine complexes incorporated in streptavidin mutants acting as host protein. Such hybrid catalysts have been shown to be good enantioselective hydrogenation catalysts for acetamidoacrylic acid. The descriptor-based models were constructed to predict enantiomeric excess (%ee) on the basis of the catalyst structures originating from docking simulations. 3D molecular descriptors for the docked ligands structures were computed. The relative arrangement of guest and host molecules was coded using distance descriptors (Rh-Cα interatomic distances); the diversity of the mutant proteins at the position S112 was coded with molecular descriptors for the sequence of three neighboring amino acids (T111-S112X-G113). The selection of testing samples for the external model validation was based on the Kohonen mapping. The final model trained by two thirds of the entire dataset was characterized by satisfactory statistical parameters for the external test set (R = 0.953 and RMS = 16.8 %ee). The proposed procedure of docking-based descriptor generation thus appears as a promising alternative to the full characterization of the complex structure by experimental or computational methods.
Metal: RhLigand type: DiphenylphosphineHost protein: Streptavidin (Sav)Anchoring strategy: SupramolecularOptimization: Chemical & geneticNotes: Computational prediction of the enantioselectivity of the hydrogenation reaction catalysed by the ArM.
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Directed Evolution of Hybrid Enzymes: Evolving Enantioselectivity of an Achiral Rh-Complex Anchored to a Protein
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Chem. Commun. 2006, 4318, 10.1039/b610461d
The concept of utilizing the methods of directed evolution for tuning the enantioselectivity of synthetic achiral metal–ligand centers anchored to proteins has been implemented experimentally for the first time.
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Direct Hydrogenation of Carbon Dioxide by an Artificial Reductase Obtained by Substituting Rhodium for Zinc in the Carbonic Anhydrase Catalytic Center. A Mechanistic Study
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ACS Catal. 2015, 5, 5397-5409, 10.1021/acscatal.5b00185
Recently, a new artificial carbonic anhydrase enzyme in which the native zinc cation has been replaced with a Rh(I) has been proposed as a new reductase that is able to efficiently catalyze the hydrogenation of olefins. In this paper, we propose the possible use of this modified enzyme in the direct hydrogenation of carbon dioxide. In our theoretical investigation, we have considered different reaction mechanisms such as reductive elimination and σ-bond metathesis. In addition, the release of the formic acid and the restoring of the catalytic cycle have also been studied. Results show that the σ-bond metathesis potential energy surface lies below the reactant species. The rate-determining step is the release of the product with an energy barrier of 12.8 kcal mol–1. On the basis of our results, we conclude that this artificial enzyme can efficiently catalyze the conversion of CO2 to HCOOH by a direct hydrogenation reaction.
Metal: RhLigand type: Amino acidHost protein: Human carbonic anhydrase II (hCAII)Anchoring strategy: Metal substitutionOptimization: ---Notes: Computational study of the reaction mechanism of the formation of HCOOH from CO2
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Diversifying Metal–Ligand Cooperative Catalysis in Semi‐Synthetic [Mn]‐Hydrogenases
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Angew. Chem. Int. Ed. 2021, 60, 13350-13357, 10.1002/anie.202100443
The reconstitution of [Mn]-hydrogenases using a series of MnI complexes is described. These complexes are designed to have an internal base or pro-base that may participate in metal–ligand cooperative catalysis or have no internal base or pro-base. Only MnI complexes with an internal base or pro-base are active for H2 activation; only [Mn]-hydrogenases incorporating such complexes are active for hydrogenase reactions. These results confirm the essential role of metal–ligand cooperation for H2 activation by the MnI complexes alone and by [Mn]-hydrogenases. Owing to the nature and position of the internal base or pro-base, the mode of metal–ligand cooperation in two active [Mn]-hydrogenases is different from that of the native [Fe]-hydrogenase. One [Mn]-hydrogenase has the highest specific activity of semi-synthetic [Mn]- and [Fe]-hydrogenases. This work demonstrates reconstitution of active artificial hydrogenases using synthetic complexes differing greatly from the native active site.
Metal: MnHost protein: Apo-[Fe]-hydrogenase from M. jannaschiiAnchoring strategy: ReconstitutionOptimization: ChemicalNotes: ---
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Enantioselective Transfer Hydrogenation of Ketone Catalysed by Artificial Metalloenzymes Derived from Bovine β-Lactoglobulin
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Chem. Commun. 2012, 48, 11984, 10.1039/c2cc36980j
Artificial metalloproteins resulting from the embedding of half-sandwich Ru(II)/Rh(III) fatty acid derivatives within β-lactoglobulin catalysed the asymmetric transfer hydrogenation of trifluoroacetophenone with modest to good conversions and fair ee's.
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Immobilization of Two Organometallic Complexes into a Single Cage to Construct Protein-Based Microcompartment
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Chem. Commun. 2016, 52, 5463-5466, 10.1039/C6CC00679E
Natural protein-based microcompartments containing multiple enzymes promote cascade reactions within cells. We use the apo-ferritin protein cage to mimic such biocompartments by immobilizing two organometallic Ir and Pd complexes into the single protein cage. Precise locations of the metals and their accumulation mechanism were studied by X-ray crystallography.
Notes: Tandem reaction (Hydrogenation and Suzuki-Miyaura coupling) to form biphenylethanol from 4-iodoacetophenone and phenylboronic acid. TON and ee are given for the tandem reaction product.
Notes: Tandem reaction (Hydrogenation and Suzuki-Miyaura coupling) to form biphenylethanol from 4-iodoacetophenone and phenylboronic acid.
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Lipase Active Site Covalent Anchoring of Rh(NHC) Catalysts: Towards Chemoselective Artificial Metalloenzymes
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Chem. Commun. 2015, 51, 6792-6795, 10.1039/c4cc09700a
A Rh(NHC) phosphonate complex reacts with the lipases cutinase and Candida antarctica lipase B resulting in the first (soluble) artificial metalloenzymes formed by covalent active site-directed hybridization. When compared to unsupported complexes, these new robust hybrids show enhanced chemoselectivity in the (competitive) hydrogenation of olefins over ketones.
Metal: RhLigand type: CarbeneHost protein: CutinaseAnchoring strategy: CovalentOptimization: ---Notes: ---
Metal: RhLigand type: CarbeneHost protein: Lipase B from C. antarctica (CALB)Anchoring strategy: CovalentOptimization: ---Notes: ---
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Merging Homogeneous Catalysis with Biocatalysis; Papain as Hydrogenation Catalyst
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Chem. Commun. 2005, 5656, 10.1039/B512138H
Papain, modified at Cys-25 with a monodentate phosphite ligand and complexed with Rh(COD)2BF4, is an active catalyst in the hydrogenation of methyl 2-acetamidoacrylate.
Metal: RhLigand type: PhosphineHost protein: Papain (PAP)Anchoring strategy: CovalentOptimization: ---Notes: ---
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Metal-Conjugated Affinity Labels: A New Concept to Create Enantioselective Artificial Metalloenzymes
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ChemistryOpen 2013, 2, 50-54, 10.1002/open.201200044
How to train a protein: Metal‐conjugated affinity labels were used to selectively position catalytically active metal centers in the binding pocket of proteases. The resulting artificial metalloenzymes achieve up to 82 % e.r. in the hydrogenation of ketones. The modular setup enables a rapid generation of artificial metalloenzyme libraries, which can be adapted to a broad range of catalytic conditions.
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Second Generation Artificial Hydrogenases Based on the Biotin- Avidin Technology: Improving Activity, Stability and Selectivity by Introduction of Enantiopure Amino Acid Spacers
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Adv. Synth. Catal. 2007, 349, 1923-1930, 10.1002/adsc.200700022
We report on our efforts to create efficient artificial metalloenzymes for the enantioselective hydrogenation of N‐protected dehydroamino acids using either avidin or streptavidin as host proteins. Introduction of chiral amino acid spacers – phenylalanine or proline – between the biotin anchor and the flexible aminodiphosphine moiety 1, combined with saturation mutagenesis at position S112X of streptavidin, affords second generation artificial hydrogenases displaying improved organic solvent tolerance, reaction rates (3‐fold) and (S)‐selectivities (up to 95 % ee for N‐acetamidoalanine and N‐acetamidophenylalanine). It is shown that these artificial metalloenzymes follow Michaelis–Menten kinetics with an increased affinity for the substrate and a higher kcat than the protein‐free catalyst (compare kcat 3.06 min−1 and KM 7.38 mM for [Rh(COD)Biot‐1]+ with kcat 12.30 min−1 and KM 4.36 mM for [Rh(COD)Biot‐(R)‐Pro‐1]+ ⊂ WT Sav). Finally, we present a straightforward protocol using Biotin‐Sepharose to immobilize artificial metalloenzymes (>92 % ee for N‐acetamidoalanine and N‐acetamidophenylalanine using [Rh(COD)Biot‐(R)‐Pro‐1]+ ⊂ Sav S112W).
Metal: RhLigand type: PhosphineHost protein: Streptavidin (Sav)Anchoring strategy: SupramolecularOptimization: Chemical & geneticNotes: ---
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Second-Generation Artificial Hydrogenases Based on the Biotin-Avidin Technology: Improving Selectivity and Organic Solvent Tolerance by Introduction of an (R)-Proline Spacer
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C. R. Chim. 2007, 10, 678-683, 10.1016/j.crci.2007.02.020
We report on our efforts to create efficient artificial metalloenzymes for the enantioselective hydrogenation of N-protected dehydroamino acids using streptavidin as host protein. Introduction of an (R)-proline spacer between the biotin anchor and the diphosphine moiety affords a versatile ligand Biot-(R)-Pro-1 which displays good (S)-selectivities in the presence of streptavidin (91% ee). The resulting artificial metalloenzyme [Rh(Biot-(R)-Pro-1)(COD)]+ ⊂ WT-Sav displays increased stability against organic solvents.
Metal: RhLigand type: PhosphineHost protein: Streptavidin (Sav)Anchoring strategy: SupramolecularOptimization: ChemicalNotes: ---
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Stereoselective Hydrogenation of Olefins Using Rhodium-Substituted Carbonic Anhydrase—A New Reductase
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Chem. - Eur. J. 2009, 15, 1370-1376, 10.1002/chem.200801673
One useful synthetic reaction missing from nature's toolbox is the direct hydrogenation of substrates using hydrogen. Instead nature uses cofactors like NADH to reduce organic substrates, which adds complexity and cost to these reductions. To create an enzyme that can directly reduce organic substrates with hydrogen, researchers have combined metal hydrogenation catalysts with proteins. One approach is an indirect link where a ligand is linked to a protein and the metal binds to the ligand. Another approach is direct linking of the metal to protein, but nonspecific binding of the metal limits this approach. Herein, we report a direct hydrogenation of olefins catalyzed by rhodium(I) bound to carbonic anhydrase (CA‐[Rh]). We minimized nonspecific binding of rhodium by replacing histidine residues on the protein surface using site‐directed mutagenesis or by chemically modifying the histidine residues. Hydrogenation catalyzed by CA‐[Rh] is slightly slower than for uncomplexed rhodium(I), but the protein environment induces stereoselectivity favoring cis‐ over trans‐stilbene by about 20:1. This enzyme is the first cofactor‐independent reductase that reduces organic molecules using hydrogen. This catalyst is a good starting point to create variants with tailored reactivity and selectivity. This strategy to insert transition metals in the active site of metalloenzymes opens opportunities to a wider range of enzyme‐catalyzed reactions.
Metal: RhLigand type: CODHost protein: Bovine carbonic anhydrase II (CA)Anchoring strategy: Metal substitutionOptimization: GeneticNotes: ---
Metal: RhLigand type: CODHost protein: Human carbonic anhydrase II (hCAII)Anchoring strategy: Metal substitutionOptimization: GeneticNotes: PDB ID 4CAC = Structure of Zn containing hCAII
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Synthesis of Hybrid Transition-Metalloproteins via Thiol-Selective Covalent Anchoring of Rh-Phosphine and Ru-Phenanthroline Complexes
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Dalton Trans. 2010, 39, 8477, 10.1039/c0dt00239a
The preparation of hybrid transition metalloproteins by thiol-selective incorporation of organometallic rhodium- and ruthenium complexes is described. Phosphine ligands and two rhodium-diphosphine complexes bearing a carboxylic acid group were coupled to the cysteine of PYP R52G, yielding a metalloenzyme active in the rhodium catalyzed hydrogenation of dimethyl itaconate. The successful coupling was shown by 31P NMR spectroscopy and ESI mass spectroscopy. In addition wild-type PYP (PYP WT), PYP R52G and ALBP were successfully modified with a (η6-arene) ruthenium(II) phenanthroline complex via a maleimide linker.
Metal: RhHost protein: Photoactive Yellow Protein (PYP)Anchoring strategy: CovalentOptimization: ---Notes: ---
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Tailoring the Active Site of Chemzymes by Using a Chemogenetic-Optimization Procedure: Towards Substrate-Specific Artificial Hydrogenases Based on the Biotin–Avidin Technology
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Angew. Chem. Int. Ed. 2005, 44, 7764-7767, 10.1002/anie.200502000
The combination of chemical‐ with genetic‐optimization strategies (i.e. chemogenetic) allows the production of artificial hydrogenases based on the biotin–avidin technology. In the spirit of enzymes, second‐coordination‐sphere interactions between the host protein (streptavidin) and the substrate (an olefin) allow fine‐tuning of the selectivity to produce either R or S hydrogenation products.
Metal: RhLigand type: PhosphineHost protein: Streptavidin (Sav)Anchoring strategy: SupramolecularOptimization: Chemical & geneticNotes: ---
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Towards the Directed Evolution of Hybrid Catalysts
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Chimia 2002, 56, 721-723, 10.2533/000942902777679920
The first step in applying the recently proposed concept concerning the application of directed evolution to the creation of selective hybrid catalysts is described, specifically the covalent attachment of Mn-salen moieties and of Cu-, Pd-, and Rh-complexes of dipyridine derivatives as well as the implantation of a diphosphine moiety in a protein, future steps being cycles of mutagenesis/screening.
Metal: MnLigand type: SalenHost protein: Papain (PAP)Anchoring strategy: CovalentOptimization: ---Notes: ---
Metal: RhLigand type: Dipyridin-2-ylmethaneHost protein: Papain (PAP)Anchoring strategy: CovalentOptimization: ---Notes: ---