Design of an enantioselective artificial metallo-hydratase enzyme containing an unnatural metal-binding amino acid

Drienovská, Ivana; Alonso‐Cotchico, Lur; Vidossich, Pietro; Lledós, Agustı́; Maréchal, Jean‐Didier; Roelfes, Gérard

doi:10.1039/c7sc03477f

Cited by 78 publications

(85 citation statements)

References 60 publications

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“…The picolinate anion activates the nucleophile and picks up ap roton from methanol; thus adopting as imilar role to that of carboxylate residues in natural and artificial metallohydratases. [29] Once 2b and Hpic have been formed,H pic interacts with I2. In this way,t he cycle for the transformation of I2 into 2a/2b catalyzed by Hpic is closed.…”

Section: Role Of Oxygen In the Synthesis Of Complexes 2-4mentioning

confidence: 78%

Inner‐Sphere Oxygen Activation Promoting Outer‐Sphere Nucleophilic Attack on Olefins

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et al. 2019

Chemistry A European J

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Alkoxylation and hydroxylation reactions of 1,5‐cyclooctadiene (cod) in an iridium complex with alcohols and water promoted by the reduction of oxygen to hydrogen peroxide are described. The exo configuration of the OH/OR groups in the products agrees with nucleophilic attack at the external face of the olefin as the key step. The reactions also require the presence of a coordinating protic acid (such as picolinic acid (Hpic)) and involve the participation of a cationic diolefin iridium(III) complex, [Ir(cod)(pic)2]+, which has been isolated. Independently, this cation is also involved in easy alkoxy group exchange reactions, which are very unusual for organic ethers. DFT studies on the mechanism of olefin alkoxylation mediated by oxygen show a low‐energy proton‐coupled electron‐transfer step connecting a superoxide–iridium(II) complex with hydroperoxide–iridium(III) intermediates, rather than peroxide complexes. Accordingly, a more complex reaction, with up to four different products, occurred upon reacting the diolefin–peroxide iridium(III) complex with Hpic. Moreover, such hydroperoxide intermediates are the origin of the regio‐ and stereoselectivity of the hydroxylation/alkoxylation reactions. If this protocol is applied to the diolefin–rhodium(I) complex [Rh(pic)(cod)], free alkyl ethers ORC8H11 (R=Me, Et) resulted, and the reaction is enantioselective if a chiral amino acid, such as l‐proline, is used instead of Hpic.

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Section: Role Of Oxygen In the Synthesis Of Complexes 2-4mentioning

confidence: 78%

Inner‐Sphere Oxygen Activation Promoting Outer‐Sphere Nucleophilic Attack on Olefins

Abril

Rı́o

López

et al. 2019

Chemistry A European J

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“…To identify beneficial mutations,e ight residues were targeted (Supporting Information, Figure S2), which are either in close proximity to pAF15 or have previously been identified to improve catalytic parameters of unrelated, LmrR-based designer enzymes. [32][33][34] Libraries targeting each position were constructed using degenerate primers (NNK codons,w hich allow for all 20 canonical amino acids) and approximately 400 library members were evaluated using the previously established screen.…”

Section: Zuschriftenmentioning

confidence: 99%

Directed Evolution of a Designer Enzyme Featuring an Unnatural Catalytic Amino Acid

et al. 2019

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The impressive rate accelerations that enzymes display in nature often result from boosting the inherent catalytic activities of side chains by their precise positioning inside a protein binding pocket. Such fine‐tuning is also possible for catalytic unnatural amino acids. Specifically, the directed evolution of a recently described designer enzyme, which utilizes an aniline side chain to promote a model hydrazone formation reaction, is reported. Consecutive rounds of directed evolution identified several mutations in the promiscuous binding pocket, in which the unnatural amino acid is embedded in the starting catalyst. When combined, these mutations boost the turnover frequency ( k cat ) of the designer enzyme by almost 100‐fold. This results from strengthening the catalytic contribution of the unnatural amino acid, as the engineered designer enzymes outperform variants, in which the aniline side chain is replaced with a catalytically inactive tyrosine residue, by more than 200‐fold.

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“…[28,29] It presents an unusually large hydrophobic and promiscuous binding pocket at the dimer interface,which has proven to be very suitable for the creation of an ovel active site through anchoring of ac atalytically active Cu II complex inside.T he resulting artificial metalloenzymes have been applied successfully in enantioselective Lewis acid catalysis. [30][31][32][33] In particular,s upramolecular assembly of the artificial metalloenzyme through combination with aC u II -phenanthroline complex proved powerful, giving rise to excellent enantioselectivity in the Friedel-Crafts alkylation reaction. [34] The diversity of reactions catalyzed by LmrR-based artificial enzymes led us to believe that the LmrR scaffold could be extended to other catalyst types,i ncluding heme-based catalysts.…”

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confidence: 99%

An Artificial Heme Enzyme for Cyclopropanation Reactions

et al. 2018

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An artificial heme enzyme was created through self‐assembly from hemin and the lactococcal multidrug resistance regulator (LmrR). The crystal structure shows the heme bound inside the hydrophobic pore of the protein, where it appears inaccessible for substrates. However, good catalytic activity and moderate enantioselectivity was observed in an abiological cyclopropanation reaction. We propose that the dynamic nature of the structure of the LmrR protein is key to the observed activity. This was supported by molecular dynamics simulations, which showed transient formation of opened conformations that allow the binding of substrates and the formation of pre‐catalytic structures.

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Design of an enantioselective artificial metallo-hydratase enzyme containing an unnatural metal-binding amino acid

Abstract: Starting from biochemical knowledge followed by computational design, an artificial metallo-hydratase comprising an unnatural metal binding amino acid was created.

Cited by 78 publications

References 60 publications

Inner‐Sphere Oxygen Activation Promoting Outer‐Sphere Nucleophilic Attack on Olefins

Inner‐Sphere Oxygen Activation Promoting Outer‐Sphere Nucleophilic Attack on Olefins

Directed Evolution of a Designer Enzyme Featuring an Unnatural Catalytic Amino Acid

An Artificial Heme Enzyme for Cyclopropanation Reactions

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