1
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Soler J, Gergel S, Hammer SC, Garcia-Borràs M. Molecular Basis for Chemoselectivity Control in Oxidations of Internal Aryl-Alkenes Catalyzed by Laboratory Evolved P450s. Chembiochem 2024:e202400066. [PMID: 38567500 DOI: 10.1002/cbic.202400066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 03/28/2024] [Accepted: 04/03/2024] [Indexed: 04/04/2024]
Abstract
P450 enzymes naturally perform selective oxidations of unfunctionalized hydrocarbon substrates, among other reactions. The adaptation of P450 enzymes to particular oxidative reactions involving alkenes is of great interest for the design of new biocatalysts. However, the mechanism that these enzymes utilize to precisely modulate the chemoselectivity and distinguishing between competing alkene double bond epoxidations and allylic C-H hydroxylations is sometimes not clear, which hampers the rational design of specific biocatalysts. In a previous work, P450LA1 was engineered in the laboratory using directed evolution to catalyze the direct oxidation of trans-b-methylstyrene to phenylacetone. The final variant, KS, was able to overcome the intrinsic preference for alkene epoxidation to directly generate a ketone product via the formation of a highly reactive carbocation intermediate. Here, additional library screening along this evolutionary lineage permitted to serendipitously detect a mutation that overcomes epoxidation and carbonyl formation by exhibiting a large selectivity of 94% towards allylic C-H hydroxylation. A multiscalar computational methodology was applied to reveal the molecular basis towards this hydroxylation preference. Enzyme modelling suggests that introduction of bulky substitution dramatically changes accessible conformations of the substrate in the active site, thus modifying the enzymatic selectivity towards terminal hydroxylation and avoiding the competing epoxidation pathway.
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Affiliation(s)
- Jordi Soler
- University of Girona, Institut de Quıḿ ica Computacional i Catàlisi (IQCC) and Departament de Química, SPAIN
| | - Sebastian Gergel
- Universitat Bielefeld, Organic Chemistry and Biocatalysis, Faculty of Chemistry, GERMANY
| | - Stephan C Hammer
- Universitat Bielefeld, Organic Chemistry and Biocatalysis, Faculty of Chemistry, GERMANY
| | - Marc Garcia-Borràs
- Universitat de Girona, Institut de Química Computacional i Catàlisi and Departament de Química, Campus de Montilivi s/n, Facultat de Ciències, Girona, España, 17071, Girona, SPAIN
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2
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Schülke KH, Fröse JS, Klein A, Garcia-Borràs M, Hammer SC. Efficient Transferase Engineering for SAM Analog Synthesis from Iodoalkanes. Chembiochem 2024:e202400079. [PMID: 38477872 DOI: 10.1002/cbic.202400079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 03/12/2024] [Accepted: 03/13/2024] [Indexed: 03/14/2024]
Abstract
S-Adenosyl-l-methionine (SAM) is an important cosubstrate in various biochemical processes, including selective methyl transfer reactions. Simple methods for the (re)generation of SAM analogs could expand the chemistry accessible with SAM-dependent transferases and go beyond methylation reactions. Here we present an efficient enzyme engineering strategy to synthesize different SAM analogs from "off-the-shelf" iodoalkanes through enzymatic alkylation of S-adenosyl-l-homocysteine (SAH). This was achieved by mutating multiple hydrophobic and structurally dynamic amino acids simultaneously. Combinatorial mutagenesis was guided by the natural amino acid diversity and generated a highly functional mutant library. This approach increased the speed as well as the scale of enzyme engineering by providing a panel of optimized enzymes with orders of magnitude higher activities for multiple substrates in just one round of enzyme engineering. The optimized enzymes exhibit catalytic efficiencies up to 31 M-1 s-1, convert various iodoalkanes, including substrates bearing cyclopropyl or aromatic moieties, and catalyze S-alkylation of SAH with very high stereoselectivities (>99 % de). We further report a high throughput chromatographic screening system for reliable and rapid SAM analog analysis. We believe that the methods and enzymes described herein will further advance the field of selective biocatalytic alkylation chemistry by enabling SAM analog regeneration with "off-the-shelf" reagents.
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Affiliation(s)
- Kai H Schülke
- Organic Chemistry and Biocatalysis, Faculty of Chemistry, Bielefeld University, Universitätsstraße 25, 33615, Bielefeld, Germany
| | - Jana S Fröse
- Organic Chemistry and Biocatalysis, Faculty of Chemistry, Bielefeld University, Universitätsstraße 25, 33615, Bielefeld, Germany
| | - Alina Klein
- Organic Chemistry and Biocatalysis, Faculty of Chemistry, Bielefeld University, Universitätsstraße 25, 33615, Bielefeld, Germany
| | - Marc Garcia-Borràs
- Department Institut de Química Computacional i Catàlisi (IQCC), Departament de Química, Universitat de Girona, 17003, Girona, Catalonia, Spain
| | - Stephan C Hammer
- Organic Chemistry and Biocatalysis, Faculty of Chemistry, Bielefeld University, Universitätsstraße 25, 33615, Bielefeld, Germany
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3
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Vargas DA, Ren X, Sengupta A, Zhu L, Roy S, Garcia-Borràs M, Houk KN, Fasan R. Biocatalytic strategy for the construction of sp 3-rich polycyclic compounds from directed evolution and computational modelling. Nat Chem 2024:10.1038/s41557-023-01435-3. [PMID: 38351380 DOI: 10.1038/s41557-023-01435-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 12/20/2023] [Indexed: 02/17/2024]
Abstract
Catalysis with engineered enzymes has provided more efficient routes for the production of active pharmaceutical agents. However, the potential of biocatalysis to assist in early-stage drug discovery campaigns remains largely untapped. In this study, we have developed a biocatalytic strategy for the construction of sp3-rich polycyclic compounds via the intramolecular cyclopropanation of benzothiophenes and related heterocycles. Two carbene transferases with complementary regioisomer selectivity were evolved to catalyse the stereoselective cyclization of benzothiophene substrates bearing diazo ester groups at the C2 or C3 position of the heterocycle. The detailed mechanisms of these reactions were elucidated by a combination of crystallographic and computational analyses. Leveraging these insights, the substrate scope of one of the biocatalysts could be expanded to include previously unreactive substrates, highlighting the value of integrating evolutionary and rational strategies to develop enzymes for new-to-nature transformations. The molecular scaffolds accessed here feature a combination of three-dimensional and stereochemical complexity with 'rule-of-three' properties, which should make them highly valuable for fragment-based drug discovery campaigns.
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Affiliation(s)
- David A Vargas
- Process Research and Development, Merck, Rahway, NJ, USA
| | - Xinkun Ren
- College of Engineering and Applied Sciences, Nanjing University, Nanjing, China
| | - Arkajyoti Sengupta
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
| | - Ledong Zhu
- Environment Research Institute, Shandong University, Qingdao, People's Republic of China
| | - Satyajit Roy
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, TX, USA
| | - Marc Garcia-Borràs
- Institut de Química Computacional i Catàlisi (IQCC), Departament de Química, Universitat de Girona, Girona, Spain
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA.
| | - Rudi Fasan
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, TX, USA.
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4
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Bloomer BJ, Joyner IA, Garcia-Borràs M, Hu DB, Garçon M, Quest A, Ugarte Montero C, Yu IF, Clark DS, Hartwig JF. Enantio- and Diastereodivergent Cyclopropanation of Allenes by Directed Evolution of an Iridium-Containing Cytochrome. J Am Chem Soc 2024; 146:1819-1824. [PMID: 38190322 DOI: 10.1021/jacs.3c13011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2024]
Abstract
Alkylidene cyclopropanes (ACPs) are valuable synthetic intermediates because of their constrained structure and opportunities for further diversification. Although routes to ACPs are known, preparations of ACPs with control of both the configuration of the cyclopropyl (R vs S) group and the geometry of the alkene (E vs Z) are unknown. We describe enzymatic cyclopropanation of allenes with ethyl diazoacetate (EDA) catalyzed by an iridium-containing cytochrome (Ir(Me)-CYP119) that controls both stereochemical elements. Two mutants of Ir(Me)-CYP119 identified by 6-codon (6c, VILAFG) saturation mutagenesis catalyze the formation of (E)-ACPs with -93% to >99% ee and >99:1 E/Z ratio with just three rounds of 96 mutants. By four additional rounds of mutagenesis, an enzyme variant was identified that forms (Z)-ACPs with up to 94% ee and a 28:72 E/Z ratio. Computational studies show that the orientation of the carbene unit dictated by the mutated positions accounts for the stereoselectivity.
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Affiliation(s)
- Brandon J Bloomer
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Division of Chemical Sciences, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Isaac A Joyner
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Division of Chemical Sciences, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Marc Garcia-Borràs
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Girona 17003, Spain
| | - Derek B Hu
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Martí Garçon
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Division of Chemical Sciences, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Andrew Quest
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Consuelo Ugarte Montero
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Isaac F Yu
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Douglas S Clark
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, United States
| | - John F Hartwig
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Division of Chemical Sciences, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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5
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Calvó-Tusell C, Liu Z, Chen K, Arnold FH, Garcia-Borràs M. Reversing the Enantioselectivity of Enzymatic Carbene N-H Insertion Through Mechanism-Guided Protein Engineering. Angew Chem Int Ed Engl 2023; 62:e202303879. [PMID: 37260412 DOI: 10.1002/anie.202303879] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 05/29/2023] [Accepted: 05/31/2023] [Indexed: 06/02/2023]
Abstract
We report a computationally driven approach to access enantiodivergent enzymatic carbene N-H insertions catalyzed by P411 enzymes. Computational modeling was employed to rationally guide engineering efforts to control the accessible conformations of a key lactone-carbene (LAC) intermediate in the enzyme active site by installing a new H-bond anchoring point. This H-bonding interaction controls the relative orientation of the reactive carbene intermediate, orienting it for an enantioselective N-nucleophilic attack by the amine substrate. By combining MD simulations and site-saturation mutagenesis and screening targeted to only two key residues, we were able to reverse the stereoselectivity of previously engineered S-selective P411 enzymes. The resulting variant, L5_FL-B3, accepts a broad scope of amine substrates for N-H insertion with excellent yields (up to >99 %), high efficiency (up to 12 300 TTN), and good enantiocontrol (up to 7 : 93 er).
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Affiliation(s)
- Carla Calvó-Tusell
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, C/M. Aurèlia Capmany, 69, 17003, Girona, Spain
| | - Zhen Liu
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E California Blvd., Pasadena, CA 91125, USA
- National Institute of Biological Sciences, Beijing, 102206, China
| | - Kai Chen
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E California Blvd., Pasadena, CA 91125, USA
- Innovative Genomics Institute, University of California, Berkeley, CA, USA
| | - Frances H Arnold
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E California Blvd., Pasadena, CA 91125, USA
| | - Marc Garcia-Borràs
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, C/M. Aurèlia Capmany, 69, 17003, Girona, Spain
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6
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Schaus L, Das A, Knight AM, Jimenez-Osés G, Houk KN, Garcia-Borràs M, Arnold FH, Huang X. Protoglobin-Catalyzed Formation of cis-Trifluoromethyl-Substituted Cyclopropanes by Carbene Transfer. Angew Chem Int Ed Engl 2023; 62:e202208936. [PMID: 36533936 PMCID: PMC9894577 DOI: 10.1002/anie.202208936] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Indexed: 12/23/2022]
Abstract
Trifluoromethyl-substituted cyclopropanes (CF3 -CPAs) constitute an important class of compounds for drug discovery. While several methods have been developed for synthesis of trans-CF3 -CPAs, stereoselective production of corresponding cis-diastereomers remains a formidable challenge. We report a biocatalyst for diastereo- and enantio-selective synthesis of cis-CF3 -CPAs with activity on a variety of alkenes. We found that an engineered protoglobin from Aeropyrnum pernix (ApePgb) can catalyze this unusual reaction at preparative scale with low-to-excellent yield (6-55 %) and enantioselectivity (17-99 % ee), depending on the substrate. Computational studies revealed that the steric environment in the active site of the protoglobin forced iron-carbenoid and substrates to adopt a pro-cis near-attack conformation. This work demonstrates the capability of enzyme catalysts to tackle challenging chemistry problems and provides a powerful means to expand the structural diversity of CF3 -CPAs for drug discovery.
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Affiliation(s)
- Lucas Schaus
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E California Blvd., Pasadena, CA 91125, USA
| | - Anuvab Das
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E California Blvd., Pasadena, CA 91125, USA
| | - Anders M Knight
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E California Blvd., Pasadena, CA 91125, USA
| | - Gonzalo Jimenez-Osés
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 800, 48160, Derio, Spain
- Ikerbasque, Basque Foundation for Science, 48013, Bilbao, Spain
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Marc Garcia-Borràs
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, C/M. Aurèlia Capmany, 69, 17003, Girona, Spain
| | - Frances H Arnold
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E California Blvd., Pasadena, CA 91125, USA
| | - Xiongyi Huang
- Department of Chemistry, Johns-Hopkins University, Baltimore, MD 21218, USA
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7
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Bloomer BJ, Natoli SN, Garcia-Borràs M, Pereira JH, Hu DB, Adams PD, Houk KN, Clark DS, Hartwig JF. Mechanistic and structural characterization of an iridium-containing cytochrome reveals kinetically relevant cofactor dynamics. Nat Catal 2023. [DOI: 10.1038/s41929-022-00899-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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8
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Ospina F, Schülke KH, Soler J, Klein A, Prosenc B, Garcia-Borràs M, Hammer SC. Selective Biocatalytic N‐Methylation of Unsaturated Heterocycles. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202213056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Felipe Ospina
- Bielefeld University: Universitat Bielefeld Faculty of Chemistry GERMANY
| | - Kai H. Schülke
- Bielefeld University: Universitat Bielefeld Faculty of Chemistry GERMANY
| | - Jordi Soler
- University of Girona: Universitat de Girona Institut de Quı́mica Computacional i Catàlisi SPAIN
| | - Alina Klein
- University of Bielefeld: Universitat Bielefeld Faculty of Chemistry GERMANY
| | - Benjamin Prosenc
- Bielefeld University: Universitat Bielefeld Faculty of Chemistry GERMANY
| | - Marc Garcia-Borràs
- University of Girona: Universitat de Girona Institut de Quı́mica Computacional i Catàlisi SPAIN
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9
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Soler J, Gergel S, Klaus C, Hammer SC, Garcia-Borràs M. Enzymatic Control over Reactive Intermediates Enables Direct Oxidation of Alkenes to Carbonyls by a P450 Iron-Oxo Species. J Am Chem Soc 2022; 144:15954-15968. [PMID: 35998887 PMCID: PMC9460782 DOI: 10.1021/jacs.2c02567] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
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The aerobic oxidation of alkenes to carbonyls is an important
and
challenging transformation in synthesis. Recently, a new P450-based
enzyme (aMOx) has been evolved in the laboratory to directly oxidize
styrenes to their corresponding aldehydes with high activity and selectivity.
The enzyme utilizes a heme-based, high-valent iron-oxo species as
a catalytic oxidant that normally epoxidizes alkenes, similar to other
catalysts. How the evolved aMOx enzyme suppresses the commonly preferred
epoxidation and catalyzes direct carbonyl formation is currently not
well understood. Here, we combine computational modelling together
with mechanistic experiments to study the reaction mechanism and unravel
the molecular basis behind the selectivity achieved by aMOx. Our results
describe that although both pathways are energetically accessible
diverging from a common covalent radical intermediate, intrinsic dynamic effects determine the strong preference for epoxidation.
We discovered that aMOx overrides these intrinsic preferences by controlling
the accessible conformations of the covalent radical intermediate.
This disfavors epoxidation and facilitates the formation of a carbocation
intermediate that generates the aldehyde product through a fast 1,2-hydride
migration. Electrostatic preorganization of the enzyme active site
also contributes to the stabilization of the carbocation intermediate.
Computations predicted that the hydride migration is stereoselective
due to the enzymatic conformational control over the intermediate
species. These predictions were corroborated by experiments using
deuterated styrene substrates, which proved that the hydride migration
is cis- and enantioselective. Our results demonstrate
that directed evolution tailored a highly specific active site that
imposes strong steric control over key fleeting biocatalytic intermediates,
which is essential for accessing the carbonyl forming pathway and
preventing competing epoxidation.
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Affiliation(s)
- Jordi Soler
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Carrer Maria Aurèlia Capmany 69, Girona 17003, Catalonia, Spain
| | - Sebastian Gergel
- Chair of Organic Chemistry and Biocatalysis, Faculty of Chemistry, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
| | - Cindy Klaus
- Chair of Organic Chemistry and Biocatalysis, Faculty of Chemistry, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
| | - Stephan C Hammer
- Chair of Organic Chemistry and Biocatalysis, Faculty of Chemistry, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
| | - Marc Garcia-Borràs
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Carrer Maria Aurèlia Capmany 69, Girona 17003, Catalonia, Spain
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10
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Fu Y, Chen H, Fu W, Garcia-Borràs M, Yang Y, Liu P. Engineered P450 Atom-Transfer Radical Cyclases are Bifunctional Biocatalysts: Reaction Mechanism and Origin of Enantioselectivity. J Am Chem Soc 2022; 144:13344-13355. [PMID: 35830682 PMCID: PMC9339536 DOI: 10.1021/jacs.2c04937] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
New-to-nature radical biocatalysis has recently emerged as a powerful strategy to tame fleeting open-shell intermediates for stereoselective transformations. In 2021, we introduced a novel metalloredox biocatalysis strategy that leverages the innate redox properties of the heme cofactor of P450 enzymes, furnishing new-to-nature atom-transfer radical cyclases (ATRCases) with excellent activity and stereoselectivity. Herein, we report a combined computational and experimental study to shed light on the mechanism and origins of enantioselectivity for this system. Molecular dynamics and quantum mechanics/molecular mechanics (QM/MM) calculations revealed an unexpected role of the key beneficial mutation I263Q. The glutamine residue serves as an essential hydrogen bond donor that engages with the carbonyl moiety of the substrate to promote bromine atom abstraction and enhance the enantioselectivity of radical cyclization. Therefore, the evolved ATRCase is a bifunctional biocatalyst, wherein the heme cofactor enables atom-transfer radical biocatalysis, while the hydrogen bond donor residue further enhances the activity and enantioselectivity. Unlike many enzymatic stereocontrol rationales based on a rigid substrate binding model, our computations demonstrate a high degree of rotational flexibility of the allyl moiety in an enzyme-substrate complex and succeeding intermediates. Therefore, the enantioselectivity is controlled by the radical cyclization transition states rather than the substrate orientation in ground-state complexes in the preceding steps. During radical cyclization, anchoring effects of the Q263 residue and steric interactions with the heme cofactor concurrently control the π-facial selectivity, allowing for highly enantioselective C-C bond formation. Our computational findings are corroborated by experiments with ATRCase mutants generated from site-directed mutagenesis.
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Affiliation(s)
- Yue Fu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Heyu Chen
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Wenzhen Fu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Marc Garcia-Borràs
- Institut de Química Computacional i Catalisi (IQCC) and Departament de Química, Universitat de Girona, Girona 17003, Spain
| | - Yang Yang
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States.,Biomolecular Science and Engineering (BMSE) Program, University of California, Santa Barbara, California 93106, United States
| | - Peng Liu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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11
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Girame H, Garcia-Borràs M, Feixas F. Changes in Protonation States of In-Pathway Residues can Alter Ligand Binding Pathways Obtained From Spontaneous Binding Molecular Dynamics Simulations. Front Mol Biosci 2022; 9:922361. [PMID: 35860361 PMCID: PMC9289141 DOI: 10.3389/fmolb.2022.922361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Accepted: 06/14/2022] [Indexed: 11/24/2022] Open
Abstract
Protein-ligand binding processes often involve changes in protonation states that can be key to recognize and orient the ligand in the binding site. The pathways through which (bio)molecules interplay to attain productively bound complexes are intricate and involve a series of interconnected intermediate and transition states. Molecular dynamics (MD) simulations and enhanced sampling techniques are commonly used to characterize the spontaneous binding of a ligand to its receptor. However, the effect of protonation state changes of in-pathway residues in spontaneous binding MD simulations remained mostly unexplored. Here, we used molecular dynamics simulations to reconstruct the trypsin-benzamidine binding pathway considering different protonation states of His57. This residue is part of the trypsin catalytic triad and is located more than 10 Å away from Asp189, which is responsible for benzamidine binding in the trypsin S1 pocket. Our MD simulations showed that the binding pathways that benzamidine follow to target the S1 binding site are critically dependent on the His57 protonation state. Binding of benzamidine frequently occurs when His57 is protonated in the delta nitrogen while the binding process is significantly less frequent when His57 is positively charged. Constant-pH MD simulations retrieved the equilibrium populations of His57 protonation states at trypsin active pH offering a clearer picture of benzamidine recognition and binding. These results indicate that properly accounting for protonation states of distal residues can be important in spontaneous binding MD simulations.
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12
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Rui J, Zhao Q, Huls AJ, Soler J, Paris JC, Chen Z, Reshetnikov V, Yang Y, Guo Y, Garcia-Borràs M, Huang X. Directed evolution of nonheme iron enzymes to access abiological radical-relay C(sp 3)-H azidation. Science 2022; 376:869-874. [PMID: 35587977 PMCID: PMC9933208 DOI: 10.1126/science.abj2830] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
We report the reprogramming of nonheme iron enzymes to catalyze an abiological C(sp3)‒H azidation reaction through iron-catalyzed radical relay. This biocatalytic transformation uses amidyl radicals as hydrogen atom abstractors and Fe(III)‒N3 intermediates as radical trapping agents. We established a high-throughput screening platform based on click chemistry for rapid evolution of the catalytic performance of identified enzymes. The final optimized variants deliver a range of azidation products with up to 10,600 total turnovers and 93% enantiomeric excess. Given the prevalence of radical relay reactions in organic synthesis and the diversity of nonheme iron enzymes, we envision that this discovery will stimulate future development of metalloenzyme catalysts for synthetically useful transformations unexplored by natural evolution.
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Affiliation(s)
- Jinyan Rui
- Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Qun Zhao
- Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Anthony J. Huls
- Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Jordi Soler
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona E-17071, Catalonia, Spain
| | - Jared C. Paris
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Zhenhong Chen
- Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Viktor Reshetnikov
- Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Yunfang Yang
- College of Chemical Enginering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, China
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213, USA,Corresponding author. (X.H.); (M.G.B.); (Y.G.)
| | - Marc Garcia-Borràs
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona E-17071, Catalonia, Spain,Corresponding author. (X.H.); (M.G.B.); (Y.G.)
| | - Xiongyi Huang
- Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218, USA.,Corresponding author. (X.H.); (M.G.B.); (Y.G.)
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13
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Liu Z, Qin ZY, Zhu L, Athavale SV, Sengupta A, Jia ZJ, Garcia-Borràs M, Houk KN, Arnold FH. An Enzymatic Platform for Primary Amination of 1-Aryl-2-alkyl Alkynes. J Am Chem Soc 2021; 144:80-85. [PMID: 34941252 DOI: 10.1021/jacs.1c11340] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Propargyl amines are versatile synthetic intermediates with numerous applications in the pharmaceutical industry. An attractive strategy for efficient preparation of these compounds is nitrene propargylic C(sp3)-H insertion. However, achieving this reaction with good chemo-, regio-, and enantioselective control has proven to be challenging. Here, we report an enzymatic platform for the enantioselective propargylic amination of alkynes using a hydroxylamine derivative as the nitrene precursor. Cytochrome P450 variant PA-G8 catalyzing this transformation was identified after eight rounds of directed evolution. A variety of 1-aryl-2-alkyl alkynes are accepted by PA-G8, including those bearing heteroaromatic rings. This biocatalytic process is efficient and selective (up to 2610 total turnover number (TTN) and 96% ee) and can be performed on preparative scale.
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Affiliation(s)
- Zhen Liu
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Zi-Yang Qin
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Ledong Zhu
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Soumitra V Athavale
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Arkajyoti Sengupta
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Zhi-Jun Jia
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Marc Garcia-Borràs
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, 17003 Girona, Spain
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Frances H Arnold
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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14
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Abstract
Decades of extensive research efforts by biochemists, organic chemists, and protein engineers have led to an understanding of the basic mechanisms of essentially all known types of enzymes, but in a formidable number of cases an essential aspect has been overlooked. The occurrence of short-lived chiral intermediates formed by symmetry-breaking of prochiral precursors in enzyme catalyzed reactions has been systematically neglected. We designate these elusive species as fleeting chiral intermediates and analyze such crucial questions as "Do such intermediates occur in homochiral form?" If so, what is the absolute configuration, and why did Nature choose that particular stereoisomeric form, even when the isolable final product may be achiral? Does the absolute configuration of a chiral product depend in any way on the absolute configuration of the fleeting chiral precursor? How does this affect the catalytic proficiency of the enzyme? If these issues continue to be unexplored, then an understanding of the mechanisms of many enzyme types remains incomplete. We have systematized the occurrence of these chiral intermediates according to their structures and enzyme types. This is followed by critical analyses of selected case studies and by final conclusions and perspectives. We hope that the fascinating concept of fleeting chiral intermediates will attract the attention of scientists, thereby opening an exciting new research field.
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Affiliation(s)
- Manfred T. Reetz
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Muelheim, Germany
- Tianjin
Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport
Economic Area, Tianjin 300308, China
| | - Marc Garcia-Borràs
- Institute
of Computational Chemistry and Catalysis (IQCC) and Departament de
Química, Universitat de Girona, Carrer Maria Aurèlia Capmany
69, 17003 Girona, Spain
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15
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Espinoza RV, Haatveit KC, Grossman SW, Tan JY, McGlade CA, Khatri Y, Newmister SA, Schmidt JJ, Garcia-Borràs M, Montgomery J, Houk KN, Sherman DH. Engineering P450 TamI as an Iterative Biocatalyst for Selective Late-Stage C-H Functionalization and Epoxidation of Tirandamycin Antibiotics. ACS Catal 2021; 11:8304-8316. [PMID: 35003829 DOI: 10.1021/acscatal.1c01460] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Iterative P450 enzymes are powerful biocatalysts for selective late-stage C-H oxidation of complex natural product scaffolds. These enzymes represent useful tools for selectivity and cascade reactions, facilitating direct access to core structure diversification. Recently, we reported the structure of the multifunctional bacterial P450 TamI and elucidated the molecular basis of its substrate binding and strict reaction sequence at distinct carbon atoms of the substrate. Here, we report the design and characterization of a toolbox of TamI biocatalysts, generated by mutations at Leu101, Leu244, and/or Leu295, that alter the native selectivity, step sequence, and number of reactions catalyzed, including the engineering of a variant capable of catalyzing a four-step oxidative cascade without the assistance of the flavoprotein and oxidative partner TamL. The tuned enzymes override inherent substrate reactivity, enabling catalyst-controlled C-H functionalization and alkene epoxidation of the tetramic acid-containing natural product tirandamycin. Five bioactive tirandamycin derivatives (6-10) were generated through TamI-mediated enzymatic synthesis. Quantum mechanics calculations and MD simulations provide important insights into the basis of altered selectivity and underlying biocatalytic mechanisms for enhanced continuous oxidation of the iterative P450 TamI.
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Affiliation(s)
- Rosa V Espinoza
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States; Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Kersti Caddell Haatveit
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - S Wald Grossman
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Jin Yi Tan
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Caylie A McGlade
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Yogan Khatri
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Sean A Newmister
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Jennifer J Schmidt
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Marc Garcia-Borràs
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - John Montgomery
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - David H Sherman
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States; Department of Medicinal Chemistry, Department of Chemistry, and Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan 48109, United States
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16
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Knorrscheidt A, Soler J, Hünecke N, Püllmann P, Garcia-Borràs M, Weissenborn MJ. Accessing Chemo- and Regioselective Benzylic and Aromatic Oxidations by Protein Engineering of an Unspecific Peroxygenase. ACS Catal 2021; 11:7327-7338. [PMID: 34631225 PMCID: PMC8496131 DOI: 10.1021/acscatal.1c00847] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 05/21/2021] [Indexed: 01/12/2023]
Abstract
![]()
Unspecific
peroxygenases (UPOs) enable oxyfunctionalizations of
a broad substrate range with unparalleled activities. Tailoring these
enzymes for chemo- and regioselective transformations represents a
grand challenge due to the difficulties in their heterologous productions.
Herein, we performed protein engineering in Saccharomyces
cerevisiae using the MthUPO from Myceliophthora thermophila. More than 5300 transformants
were screened. This protein engineering led to a significant reshaping
of the active site as elucidated by computational modelling. The reshaping
was responsible for the increased oxyfunctionalization activity, with
improved kcat/Km values of up to 16.5-fold for the model substrate 5-nitro-1,3-benzodioxole.
Moreover, variants were identified with high chemo- and regioselectivities
in the oxyfunctionalization of aromatic and benzylic carbons, respectively.
The benzylic hydroxylation was demonstrated to perform with enantioselectivities
of up to 95% ee. The proposed evolutionary protocol
and rationalization of the enhanced activities and selectivities acquired
by MthUPO variants represent a step forward toward
the use and implementation of UPOs in biocatalytic synthetic pathways
of industrial interest.
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Affiliation(s)
- Anja Knorrscheidt
- Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120 Halle, Germany
| | - Jordi Soler
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, Carrer Maria Aurèlia Capmany 69, 17003 Girona, Catalonia, Spain
| | - Nicole Hünecke
- Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120 Halle, Germany
| | - Pascal Püllmann
- Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120 Halle, Germany
| | - Marc Garcia-Borràs
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, Carrer Maria Aurèlia Capmany 69, 17003 Girona, Catalonia, Spain
| | - Martin J. Weissenborn
- Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120 Halle, Germany
- Institute of Chemistry, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 2, 06120 Halle, Germany
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17
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Garcia-Borràs M, Kan SBJ, Lewis RD, Tang A, Jimenez-Osés G, Arnold FH, Houk KN. Origin and Control of Chemoselectivity in Cytochrome c Catalyzed Carbene Transfer into Si-H and N-H bonds. J Am Chem Soc 2021; 143:7114-7123. [PMID: 33909977 DOI: 10.1021/jacs.1c02146] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A cytochrome c heme protein was recently engineered to catalyze the formation of carbon-silicon bonds via carbene insertion into Si-H bonds, a reaction that was not previously known to be catalyzed by a protein. High chemoselectivity toward C-Si bond formation over competing C-N bond formation was achieved, although this trait was not screened for during directed evolution. Using computational and experimental tools, we now establish that activity and chemoselectivity are modulated by conformational dynamics of a protein loop that covers the substrate access to the iron-carbene active species. Mutagenesis of residues computationally predicted to control the loop conformation altered the protein's chemoselectivity from preferred silylation to preferred amination of a substrate containing both N-H and Si-H functionalities. We demonstrate that information on protein structure and conformational dynamics, combined with knowledge of mechanism, leads to understanding of how non-natural and selective chemical transformations can be introduced into the biological world.
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Affiliation(s)
- Marc Garcia-Borràs
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States.,Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Carrer Maria Aurèlia Capmany 69, 17003 Girona, Spain
| | - S B Jennifer Kan
- Division of Chemistry and Chemical Engineering 210-41, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States
| | - Russell D Lewis
- Division of Biology and Bioengineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States
| | - Allison Tang
- Division of Chemistry and Chemical Engineering 210-41, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States
| | | | - Frances H Arnold
- Division of Biology and Bioengineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States.,Division of Chemistry and Chemical Engineering 210-41, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
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18
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Knorrscheidt A, Soler J, Hünecke N, Püllmann P, Garcia-Borràs M, Weissenborn MJ. Simultaneous screening of multiple substrates with an unspecific peroxygenase enabled modified alkane and alkene oxyfunctionalisations. Catal Sci Technol 2021. [DOI: 10.1039/d0cy02457k] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Protein engineering of an unspecific peroxygenase (UPO) was performed with three substrates and six products in parallel by a high throughput GC-MS setup. Modified chemo- and regioselective variants were identified for aliphatic substrates.
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Affiliation(s)
- Anja Knorrscheidt
- Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120 Halle (Saale), Germany
| | - Jordi Soler
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, Carrer Maria Aurèlia Capmany 69, Girona 17003, Catalonia, Spain
| | - Nicole Hünecke
- Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120 Halle (Saale), Germany
| | - Pascal Püllmann
- Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120 Halle (Saale), Germany
| | - Marc Garcia-Borràs
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, Carrer Maria Aurèlia Capmany 69, Girona 17003, Catalonia, Spain
| | - Martin J. Weissenborn
- Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120 Halle (Saale), Germany
- Institute of Chemistry, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 2, 06120 Halle (Saale), Germany
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19
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Newmister SA, Srivastava KR, Espinoza RV, Caddell Haatveit K, Khatri Y, Martini RM, Garcia-Borràs M, Podust LM, Houk KN, Sherman DH. Molecular Basis of Iterative C─H Oxidation by TamI, a Multifunctional P450 monooxygenase from the Tirandamycin Biosynthetic Pathway. ACS Catal 2020; 10:13445-13454. [PMID: 33569241 DOI: 10.1021/acscatal.0c03248] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Biocatalysis offers an expanding and powerful strategy to construct and diversify complex molecules by C─H bond functionalization. Due to their high selectivity, enzymes have become an essential tool for C─H bond functionalization and offer complementary reactivity to small-molecule catalysts. Hemoproteins, particularly cytochromes P450, have proven effective for selective oxidation of unactivated C─H bonds. Previously, we reported the in vitro characterization of an oxidative tailoring cascade in which TamI, a multifunctional P450 functions co-dependently with the TamL flavoprotein to catalyze regio- and stereoselective hydroxylations and epoxidation to yield tirandamycin A and tirandamycin B. TamI follows a defined order including 1) C10 hydroxylation, 2) C11/C12 epoxidation, and 3) C18 hydroxylation. Here we present a structural, biochemical, and computational investigation of TamI to understand the molecular basis of its substrate binding, diverse reactivity, and specific reaction sequence. The crystal structure of TamI in complex with tirandamycin C together with molecular dynamics simulations and targeted mutagenesis suggest that hydrophobic interactions with the polyene chain of its natural substrate are critical for molecular recognition. QM calculations and molecular dynamics simulations of TamI with variant substrates provided detailed information on the molecular basis of sequential reactivity, and pattern of regio- and stereo-selectivity in catalyzing the three-step oxidative cascade.
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Affiliation(s)
- Sean A. Newmister
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Kinshuk Raj Srivastava
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Laboratory of Biocatalysis & Enzyme Engineering, Regional Centre for Biotechnology, Faridabad, Haryana, India
| | - Rosa V. Espinoza
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Kersti Caddell Haatveit
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Yogan Khatri
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Rachel M. Martini
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Marc Garcia-Borràs
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Larissa M. Podust
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California 92093, United States
| | - K. N. Houk
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
| | - David. H. Sherman
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Micobiology & Immunology, University of Michigan, Ann Arbor, Michigan 48109, United States
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20
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Bähr S, Brinkmann-Chen S, Garcia-Borràs M, Roberts JM, Katsoulis DE, Houk KN, Arnold FH. Selective Enzymatic Oxidation of Silanes to Silanols. Angew Chem Int Ed Engl 2020; 59:15507-15511. [PMID: 32212229 PMCID: PMC7511438 DOI: 10.1002/anie.202002861] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Indexed: 11/08/2022]
Abstract
Compared to the biological world's rich chemistry for functionalizing carbon, enzymatic transformations of the heavier homologue silicon are rare. We report that a wild-type cytochrome P450 monooxygenase (P450BM3 from Bacillus megaterium, CYP102A1) has promiscuous activity for oxidation of hydrosilanes to give silanols. Directed evolution was applied to enhance this non-native activity and create a highly efficient catalyst for selective silane oxidation under mild conditions with oxygen as the terminal oxidant. The evolved enzyme leaves C-H bonds present in the silane substrates untouched, and this biotransformation does not lead to disiloxane formation, a common problem in silanol syntheses. Computational studies reveal that catalysis proceeds through hydrogen atom abstraction followed by radical rebound, as observed in the native C-H hydroxylation mechanism of the P450 enzyme. This enzymatic silane oxidation extends nature's impressive catalytic repertoire.
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Affiliation(s)
- Susanne Bähr
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 East California Blvd, Pasadena, CA, 91125, USA
| | - Sabine Brinkmann-Chen
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 East California Blvd, Pasadena, CA, 91125, USA
| | - Marc Garcia-Borràs
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
- Present address: Institut de Química Computacional i Catàlisi (IQCC), Departament de Química, Universitat de Girona, Girona, Spain
| | - John M Roberts
- Dow Core R&D, 633 Washington Street, Midland, MI, 48674, USA
| | | | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
| | - Frances H Arnold
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 East California Blvd, Pasadena, CA, 91125, USA
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21
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Semivrazhskaya O, Aroua S, Yulikov M, Romero-Rivera A, Stevenson S, Garcia-Borràs M, Osuna S, Yamakoshi Y. Regioselective Synthesis and Characterization of Tris- and Tetra-Prato Adducts of M 3N@C 80 (M = Y, Gd). J Am Chem Soc 2020; 142:12954-12965. [PMID: 32586092 DOI: 10.1021/jacs.9b13768] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The tris- and tetra-adducts of M3N@Ih-C80 metallofullerenes were synthesized and characterized for the first time. The 1,3-dipolar cycloaddition (Prato reaction) of Y3N@Ih-C80 and Gd3N@Ih-C80 with an excess of N-ethylglycine and formaldehyde provided tris- and tetra-fulleropyrrolidine adducts in a regioselective manner. Purification by HPLC and analyses of the isolated peaks by NMR, MS, and vis-NIR spectra revealed that the major products were four tris- and one tetra-isomers for both Y3N@Ih-C80 and Gd3N@Ih-C80. Considering the large number of possible isomers (e.g., at least 1140 isomers for the tris-adduct), the limited number of isomers obtained indicated that the reactions proceeded with high regioselectivity. NMR analyses of the Y3N@Ih-C80 adducts found that the tris-adducts were all-[6,6]- or [6,6][6,6][5,6]-isomers and that some showed mutual isomerization or remained intact at room temperature. The tetra-adduct obtained as a major product was all-[6,6] and stable. For the structural elucidation of Gd3N@Ih-C80 tris- and tetra-adducts, density functional theory (DFT) calculations were performed to estimate the relative stabilities of tris- and tetra-adducts formed upon Prato functionalization of the most pyramidalized regions of the fullerene structure. The most stable structures corresponded to additions on the most pyramidalized (i.e., strained) bonds. Taking together the experimental vis-NIR spectra, NMR assignments, and the computed relative DFT stabilities of the potential tris- and tetra-adducts, the structures of the isolated adducts were elucidated. Electron resonance (ESR) measurements measurements of pristine, bis-, and tris-adducts of Gd3N@C80 suggested that the rotation of the endohedral metal cluster slowed upon increase of the addition numbers to C80 cage, which is favored for accommodating the Gd atoms of the relatively large Gd3N cluster inner space at the sp3 addition sites. This is presumably related to the high regioselectivity in the Prato addition reaction driven by the strain release of the Gd3N@C80 fullerene structure.
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Affiliation(s)
- Olesya Semivrazhskaya
- Laboratorium für Organische Chemie, ETH Zürich, Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland
| | - Safwan Aroua
- Laboratorium für Organische Chemie, ETH Zürich, Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland
| | - Maxim Yulikov
- Laboratorium für Physikalische Chemie, ETH Zürich, Vladimir-Prelog-Weg 1, 8093 Zürich, Switzerland
| | - Adrian Romero-Rivera
- Institut de Quı́mica Computacional i Catàlisi (IQCC) and Departament de Quı́mica, Universitat de Girona, Maria Aurelia Capmany 69, 17003 Girona, Catalonia, Spain
| | - Steven Stevenson
- Department of Chemistry, Purdue University Fort Wayne, Fort Wayne, Indiana 46805, United States
| | - Marc Garcia-Borràs
- Institut de Quı́mica Computacional i Catàlisi (IQCC) and Departament de Quı́mica, Universitat de Girona, Maria Aurelia Capmany 69, 17003 Girona, Catalonia, Spain
| | - Sílvia Osuna
- Institut de Quı́mica Computacional i Catàlisi (IQCC) and Departament de Quı́mica, Universitat de Girona, Maria Aurelia Capmany 69, 17003 Girona, Catalonia, Spain.,ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Catalonia, Spain
| | - Yoko Yamakoshi
- Laboratorium für Organische Chemie, ETH Zürich, Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland
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22
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Calzadiaz-Ramirez L, Calvó-Tusell C, Stoffel GMM, Lindner SN, Osuna S, Erb TJ, Garcia-Borràs M, Bar-Even A, Acevedo-Rocha CG. In Vivo Selection for Formate Dehydrogenases with High Efficiency and Specificity toward NADP . ACS Catal 2020; 10:7512-7525. [PMID: 32733773 PMCID: PMC7384739 DOI: 10.1021/acscatal.0c01487] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 06/06/2020] [Indexed: 02/06/2023]
Abstract
The efficient regeneration of cofactors is vital for the establishment of biocatalytic processes. Formate is an ideal electron donor for cofactor regeneration due to its general availability, low reduction potential, and benign byproduct (CO2). However, formate dehydrogenases (FDHs) are usually specific to NAD+, such that NADPH regeneration with formate is challenging. Previous studies reported naturally occurring FDHs or engineered FDHs that accept NADP+, but these enzymes show low kinetic efficiencies and specificities. Here, we harness the power of natural selection to engineer FDH variants to simultaneously optimize three properties: kinetic efficiency with NADP+, specificity toward NADP+, and affinity toward formate. By simultaneously mutating multiple residues of FDH from Pseudomonas sp. 101, which exhibits practically no activity toward NADP+, we generate a library of >106 variants. We introduce this library into an E. coli strain that cannot produce NADPH. By selecting for growth with formate as the sole NADPH source, we isolate several enzyme variants that support efficient NADPH regeneration. We find that the kinetically superior enzyme variant, harboring five mutations, has 5-fold higher efficiency and 14-fold higher specificity in comparison to the best enzyme previously engineered, while retaining high affinity toward formate. By using molecular dynamics simulations, we reveal the contribution of each mutation to the superior kinetics of this variant. We further determine how nonadditive epistatic effects improve multiple parameters simultaneously. Our work demonstrates the capacity of in vivo selection to identify highly proficient enzyme variants carrying multiple mutations which would be almost impossible to find using conventional screening methods.
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Affiliation(s)
| | - Carla Calvó-Tusell
- Institut de Quı́mica Computacional i Catàlisi and Departament de Quı́mica, Universitat de Girona, Carrer Maria Aurèlia Capmany 69, Girona 17003, Catalonia, Spain
| | - Gabriele M. M. Stoffel
- Max Planck Institute of Terrestrial Microbiology, Karl-von-Frisch-Straße 10, D-35043 Marburg, Germany
| | - Steffen N. Lindner
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Sílvia Osuna
- Institut de Quı́mica Computacional i Catàlisi and Departament de Quı́mica, Universitat de Girona, Carrer Maria Aurèlia Capmany 69, Girona 17003, Catalonia, Spain
- ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain
| | - Tobias J. Erb
- Max Planck Institute of Terrestrial Microbiology, Karl-von-Frisch-Straße 10, D-35043 Marburg, Germany
- LOEWE Research Center for Synthetic Microbiology (SYNMIKRO), Karl-von-Frisch-Straße 16, D-35043 Marburg, Germany
| | - Marc Garcia-Borràs
- Institut de Quı́mica Computacional i Catàlisi and Departament de Quı́mica, Universitat de Girona, Carrer Maria Aurèlia Capmany 69, Girona 17003, Catalonia, Spain
| | - Arren Bar-Even
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
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23
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Krone MW, Albanese KI, Leighton GO, He CQ, Lee GY, Garcia-Borràs M, Guseman AJ, Williams DC, Houk KN, Brustad EM, Waters ML. Thermodynamic consequences of Tyr to Trp mutations in the cation-π-mediated binding of trimethyllysine by the HP1 chromodomain. Chem Sci 2020; 11:3495-3500. [PMID: 34109021 PMCID: PMC8152637 DOI: 10.1039/d0sc00227e] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Evolution has converged on cation–π interactions for recognition of quaternary alkyl ammonium groups such as trimethyllysine (Kme3). While computational modelling indicates that Trp provides the strongest cation–π interaction of the native aromatic amino acids, there is limited corroborative data from measurements within proteins. Herein we investigate a Tyr to Trp mutation in the binding pocket of the HP1 chromodomain, a reader protein that recognizes Kme3. Binding studies demonstrate that the Trp-mediated cation–π interaction is about −5 kcal mol−1 stronger, and the Y24W crystal structure shows that the mutation is not perturbing. Quantum mechanical calculations indicate that greater enthalpic binding is predominantly due to increased cation–π interactions. NMR studies indicate that differences in the unbound state of the Y24W mutation lead to enthalpy–entropy compensation. These results provide direct experimental quantification of Trp versus Tyr in a cation–π interaction and afford insight into the conservation of aromatic cage residues in Kme3 reader domains. In this work, we experimentally validate that tryptophan provides the strongest cation–π binding interaction among aromatic amino acids and also lend insight into the importance of residue identity in trimethyllysine recognition by reader proteins.![]()
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Affiliation(s)
- Mackenzie W Krone
- University of North Carolina at Chapel Hill 131 South Road, Campus Box 3290 Chapel Hill NC 27599 USA
| | - Katherine I Albanese
- University of North Carolina at Chapel Hill 131 South Road, Campus Box 3290 Chapel Hill NC 27599 USA
| | - Gage O Leighton
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill 120 Mason Farm Rd, Campus Box 7260 Chapel Hill NC 27599 USA
| | - Cyndi Qixin He
- Department of Chemistry and Biochemistry, University of California at Los Angeles 607 Charles E. Young Drive East, Box 951569 Los Angeles CA 90095-1569 USA
| | - Ga Young Lee
- Department of Chemistry and Biochemistry, University of California at Los Angeles 607 Charles E. Young Drive East, Box 951569 Los Angeles CA 90095-1569 USA
| | - Marc Garcia-Borràs
- Department of Chemistry and Biochemistry, University of California at Los Angeles 607 Charles E. Young Drive East, Box 951569 Los Angeles CA 90095-1569 USA
| | - Alex J Guseman
- University of North Carolina at Chapel Hill 131 South Road, Campus Box 3290 Chapel Hill NC 27599 USA
| | - David C Williams
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill Campus Box 7525, Brinkhous-Bullitt Building Chapel Hill NC 27599 USA.,Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill 450 West Drive Chapel Hill NC 27599 USA
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California at Los Angeles 607 Charles E. Young Drive East, Box 951569 Los Angeles CA 90095-1569 USA
| | - Eric M Brustad
- University of North Carolina at Chapel Hill 131 South Road, Campus Box 3290 Chapel Hill NC 27599 USA
| | - Marcey L Waters
- University of North Carolina at Chapel Hill 131 South Road, Campus Box 3290 Chapel Hill NC 27599 USA
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24
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DeMars MD, Samora NL, Yang S, Garcia-Borràs M, Sanders JN, Houk KN, Podust LM, Sherman DH. Exploring the molecular basis for substrate specificity in homologous macrolide biosynthetic cytochromes P450. J Biol Chem 2019; 294:15947-15961. [PMID: 31488542 PMCID: PMC6827315 DOI: 10.1074/jbc.ra119.010352] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 08/30/2019] [Indexed: 11/06/2022] Open
Abstract
Cytochromes P450 (P450s) are nature's catalysts of choice for performing demanding and physiologically vital oxidation reactions. Biochemical characterization of these enzymes over the past decades has provided detailed mechanistic insight and highlighted the diversity of substrates P450s accommodate and the spectrum of oxidative transformations they catalyze. Previously, we discovered that the bacterial P450 MycCI from the mycinamicin biosynthetic pathway in Micromonospora griseorubida possesses an unusually broad substrate scope, whereas the homologous P450 from tylosin-producing Streptomyces fradiae (TylHI) exhibits a high degree of specificity for its native substrate. Here, using biochemical, structural, and computational approaches, we aimed to understand the molecular basis for the disparate reactivity profiles of these two P450s. Turnover and equilibrium binding experiments with substrate analogs revealed that TylHI strictly prefers 16-membered ring macrolides bearing the deoxyamino sugar mycaminose. To help rationalize these results, we solved the X-ray crystal structure of TylHI in complex with its native substrate at 1.99-Å resolution and assayed several site-directed mutants. We also conducted molecular dynamics simulations of TylHI and MycCI and biochemically characterized a third P450 homolog from the chalcomycin biosynthetic pathway in Streptomyces bikiniensis These studies provided a basis for constructing P450 chimeras to gain further insight into the features dictating the differences in reaction profile among these structurally and functionally related enzymes, ultimately unveiling the central roles of key loop regions in influencing substrate binding and turnover. Our work highlights the complex nature of P450/substrate interactions and raises interesting questions regarding the evolution of functional diversity among biosynthetic enzymes.
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Affiliation(s)
- Matthew D DeMars
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109
| | - Nathan L Samora
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, California 92093
| | - Song Yang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095
| | - Marc Garcia-Borràs
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095
| | - Jacob N Sanders
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095
| | - Larissa M Podust
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, California 92093
| | - David H Sherman
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan 48109
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25
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Liosi K, Romero-Rivera A, Semivrazhskaya O, Caniglia CD, Garcia-Borràs M, Trapp N, Osuna S, Yamakoshi Y. Site-Selectivity of Prato Additions to C 70: Experimental and Theoretical Studies of a New Thermodynamic Product at the dd-[5,6]-Junction. Org Lett 2019; 21:5162-5166. [PMID: 31199152 DOI: 10.1021/acs.orglett.9b01756] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Three Prato monoadduct isomers were synthesized and structurally characterized by 1H, 13C NMR spectra and single-crystal X-ray diffraction, and one adduct on the dd-[5,6]-bond was found as the first example of a Prato [5,6]-adduct of C70. To investigate the mechanism in the generation of this dd-[5,6]-adduct, computational studies were employed to show that it was thermodynamically obtained by sigmatropic rearrangement from the presumed initial kinetic product de-[6,6]-adduct.
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Affiliation(s)
- Korinne Liosi
- Laboratorium für Organische Chemie , ETH Zürich , Vladimir-Prelog-Weg 3 , CH-8093 Zürich , Switzerland
| | - Adrian Romero-Rivera
- CompBioLab group, Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química , Universitat de Girona , Campus Montilivi , 17071 Girona , Catalonia , Spain
| | - Olesya Semivrazhskaya
- Laboratorium für Organische Chemie , ETH Zürich , Vladimir-Prelog-Weg 3 , CH-8093 Zürich , Switzerland
| | - Caravaggio D Caniglia
- Laboratorium für Organische Chemie , ETH Zürich , Vladimir-Prelog-Weg 3 , CH-8093 Zürich , Switzerland
| | - Marc Garcia-Borràs
- CompBioLab group, Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química , Universitat de Girona , Campus Montilivi , 17071 Girona , Catalonia , Spain
| | - Nils Trapp
- Laboratorium für Organische Chemie , ETH Zürich , Vladimir-Prelog-Weg 3 , CH-8093 Zürich , Switzerland
| | - Sílvia Osuna
- CompBioLab group, Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química , Universitat de Girona , Campus Montilivi , 17071 Girona , Catalonia , Spain.,ICREA , Pg. Lluís Companys 23 , 08010 Barcelona , Catalonia , Spain
| | - Yoko Yamakoshi
- Laboratorium für Organische Chemie , ETH Zürich , Vladimir-Prelog-Weg 3 , CH-8093 Zürich , Switzerland
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26
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Semivrazhskaya O, Romero-Rivera A, Aroua S, Troyanov SI, Garcia-Borràs M, Stevenson S, Osuna S, Yamakoshi Y. Structures of Gd 3N@C 80 Prato Bis-Adducts: Crystal Structure, Thermal Isomerization, and Computational Study. J Am Chem Soc 2019; 141:10988-10993. [PMID: 31266302 DOI: 10.1021/jacs.9b05603] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The structures of two bis-ethylpyrrolidinoadducts of Gd3N@Ih-C80, obtained by regioselective 1,3-dipolar cycloadditions, were elucidated by single crystal X-ray, visible-near infrared (vis-NIR) spectra, studies on their thermal isomerization, and theoretical calculations. The structure of the minor-bis-adduct reveals a C2-symmetric carbon cage with [6,6][6,6]-addition sites and with an endohedral Gd3N cluster that is completely flattened. This is the first example of a crystal structure of Gd3N@Ih-C80 derivatives. The structure of the major-bis-adduct was inferred by the vis-NIR spectrum being corresponded to the structure of a previously reported major-bis-adduct of Y3N@Ih-C80 known to have an asymmetric [6,6][6,6]-structure. Based on experimental results showing that the minor-bis-adduct of Gd3N@Ih-C80 isomerized to the major-adduct, a possible second addition site was elucidated with support from density functional theory calculations.
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Affiliation(s)
- Olesya Semivrazhskaya
- Laboratorium für Organische Chemie, ETH Zürich , Vladimir-Prelog-Weg 3 , CH8093 Zürich , Switzerland
| | - Adrian Romero-Rivera
- CompBioLab, Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química , Universitat de Girona , Campus Montilivi, 17071 Girona , Catalonia , Spain
| | - Safwan Aroua
- Laboratorium für Organische Chemie, ETH Zürich , Vladimir-Prelog-Weg 3 , CH8093 Zürich , Switzerland
| | - Sergey I Troyanov
- Department of Chemistry , Moscow State University , Leninskie gory, 119991 Moscow , Russia
| | - Marc Garcia-Borràs
- CompBioLab, Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química , Universitat de Girona , Campus Montilivi, 17071 Girona , Catalonia , Spain
| | - Steven Stevenson
- Department of Chemistry , Purdue University Fort Wayne , Fort Wayne , Indiana 46805 , United States
| | - Sílvia Osuna
- CompBioLab, Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química , Universitat de Girona , Campus Montilivi, 17071 Girona , Catalonia , Spain.,ICREA , Pg. Lluís Companys 23 , 08010 Barcelona , Catalonia , Spain
| | - Yoko Yamakoshi
- Laboratorium für Organische Chemie, ETH Zürich , Vladimir-Prelog-Weg 3 , CH8093 Zürich , Switzerland
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27
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Yang Z, Jamieson CS, Xue XS, Garcia-Borràs M, Benton T, Dong X, Liu F, Houk K. Mechanisms and Dynamics of Reactions Involving Entropic Intermediates. Trends in Chemistry 2019. [DOI: 10.1016/j.trechm.2019.01.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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28
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Huang X, Garcia-Borràs M, Miao K, Kan SBJ, Zutshi A, Houk KN, Arnold FH. A Biocatalytic Platform for Synthesis of Chiral α-Trifluoromethylated Organoborons. ACS Cent Sci 2019; 5:270-276. [PMID: 30834315 PMCID: PMC6396380 DOI: 10.1021/acscentsci.8b00679] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Indexed: 05/04/2023]
Abstract
There are few biocatalytic transformations that produce fluorine-containing molecules prevalent in modern pharmaceuticals. To expand the scope of biocatalysis for organofluorine synthesis, we have developed an enzymatic platform for highly enantioselective carbene B-H bond insertion to yield versatile α-trifluoromethylated (α-CF3) organoborons, an important class of organofluorine molecules that contain stereogenic centers bearing both CF3 and boron groups. In contrast to current "carbene transferase" enzymes that use a limited set of simple diazo compounds as carbene precursors, this system based on Rhodothermus marinus cytochrome c (Rma cyt c) can accept a broad range of trifluorodiazo alkanes and deliver versatile chiral α-CF3 organoborons with total turnovers up to 2870 and enantiomeric ratios up to 98.5:1.5. Computational modeling reveals that this broad diazo scope is enabled by an active-site environment that directs the alkyl substituent on the heme CF3-carbene intermediate toward the solvent-exposed face, thereby allowing the protein to accommodate diazo compounds with diverse structural features.
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Affiliation(s)
- Xiongyi Huang
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - Marc Garcia-Borràs
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, California 90095, United States
| | - Kun Miao
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - S. B. Jennifer Kan
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - Arjun Zutshi
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - K. N. Houk
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, California 90095, United States
| | - Frances H. Arnold
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
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29
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García-Simón C, Monferrer A, Garcia-Borràs M, Imaz I, Maspoch D, Costas M, Ribas X. Size-selective encapsulation of C 60 and C 60-derivatives within an adaptable naphthalene-based tetragonal prismatic supramolecular nanocapsule. Chem Commun (Camb) 2019; 55:798-801. [PMID: 30570641 DOI: 10.1039/c8cc07886f] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A novel naphthalene-based 5·(BArF)8 capsule allows for the size-selective inclusion of C60 from fullerene mixtures. Its size selectivity towards C60 has been rationalized by its dynamic adaptability in solution that has been investigated by molecular dynamics. Additionally, 5·(BArF)8 encapsulates C60-derivatives such as C60-PCBM and N-methylpyrrolidine-C60. The latter can be separated from C60 since 5·(BArF)8 displays distinct affinity for them.
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Affiliation(s)
- Cristina García-Simón
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona, E-17003, Catalonia, Spain.
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30
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Caddell Haatveit K, Garcia-Borràs M, Houk KN. Computational Protocol to Understand P450 Mechanisms and Design of Efficient and Selective Biocatalysts. Front Chem 2019; 6:663. [PMID: 30687699 PMCID: PMC6336901 DOI: 10.3389/fchem.2018.00663] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 12/20/2018] [Indexed: 11/13/2022] Open
Abstract
Cytochrome P450 enzymes have gained significant interest as selective oxidants in late-stage chemical synthesis. Their broad substrate scope enables them to be good candidates for their use in non-natural reactivity. Directed evolution evolves new enzyme biocatalysts that promote alternative reactivity for chemical synthesis. While directed evolution has proven useful in developing biocatalysts for specific purposes, this process is very time and labor intensive, and therefore not easily repurposed. Computational analysis of these P450 enzymes provides great insights into the broad substrate scope, the variety of reactions catalyzed, the binding specificity and the study of novel biosynthetic reaction mechanisms. By discovering new P450s and studying their reactivities, we uncover new insights into how this reactivity can be harnessed. We discuss a standard protocol using both DFT calculations and MD simulations to study a variety of cytochrome P450 enzymes. The approach entails theozyme models to study the mechanism and transition states via DFT calculations and subsequent MD simulations to understand the conformational poses and binding mechanisms within the enzyme. We discuss a few examples done in collaboration with the Tang and Sherman/Montgomery groups toward elucidating enzyme mechanisms and rationally designing new enzyme mutants as tools for selective C-H functionalization methods.
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Affiliation(s)
- Kersti Caddell Haatveit
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, United States
| | - Marc Garcia-Borràs
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, United States
| | - Kendall N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, United States
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31
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Xue XS, Jamieson CS, Garcia-Borràs M, Dong X, Yang Z, Houk KN. Ambimodal Trispericyclic Transition State and Dynamic Control of Periselectivity. J Am Chem Soc 2019; 141:1217-1221. [DOI: 10.1021/jacs.8b12674] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Xiao-Song Xue
- State Key Laboratory
of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Cooper S. Jamieson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Marc Garcia-Borràs
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Xiaofei Dong
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Zhongyue Yang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - K. N. Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
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32
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Li G, Garcia-Borràs M, Fürst MJLJ, Ilie A, Fraaije MW, Houk KN, Reetz MT. Overriding Traditional Electronic Effects in Biocatalytic Baeyer-Villiger Reactions by Directed Evolution. J Am Chem Soc 2018; 140:10464-10472. [PMID: 30044629 DOI: 10.1021/jacs.8b04742] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Controlling the regioselectivity of Baeyer-Villiger (BV) reactions remains an ongoing issue in organic chemistry, be it by synthetic catalysts or enzymes of the type Baeyer-Villiger monooxygenases (BVMOs). Herein, we address the challenging problem of switching normal to abnormal BVMO regioselectivity by directed evolution using three linear ketones as substrates, which are not structurally biased toward abnormal reactivity. Upon applying iterative saturation mutagenesis at sites lining the binding pocket of the thermostable BVMO from Thermocrispum municipale DSM 44069 (TmCHMO) and using 4-phenyl-2-butanone as substrate, the regioselectivity was reversed from 99:1 (wild-type enzyme in favor of the normal product undergoing 2-phenylethyl migration) to 2:98 in favor of methyl migration when applying the best mutant. This also stands in stark contrast to the respective reaction using the synthetic reagent m-CPBA, which provides solely the normal product. Reversal of regioselectivity was also achieved in the BV reaction of two other linear ketones. Kinetic parameters and melting temperatures revealed that most of the evolved mutants retained catalytic activity, as well as thermostability. In order to shed light on the origin of switched regioselectivity in reactions of 4-phenyl-2-butanone and phenylacetone, extensive QM/MM and MD simulations were performed. It was found that the mutations introduced by directed evolution induce crucial changes in the conformation of the respective Criegee intermediates and transition states in the binding pocket of the enzyme. In mutants that destabilize the normally preferred migration transition state, a reversal of regioselectivity is observed. This conformational control of regioselectivity overrides electronic control, which normally causes preferential migration of the group that is best able to stabilize positive charge. The results can be expected to aid future protein engineering of BVMOs.
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Affiliation(s)
- Guangyue Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests/Key Laboratory of Control of Biological Hazard Factors (Plant Origin) for Agri-product Quality and Safety, Ministry of Agriculture , Institute of Plant Protection, Chinese Academy of Agricultural Sciences , Beijing 100081 , China.,Max-Planck-Institut für Kohlenforschung , Kaiser-Wilhelm-Platz 1 , 45470 Mülheim , Germany.,Department of Chemistry , Philipps-University , Hans-Meerwein-Strasse 4 , 35032 Marburg , Germany
| | - Marc Garcia-Borràs
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
| | - Maximilian J L J Fürst
- Molecular Enzymology Group , University of Groningen , Nijenborgh 4 , 9747 AG Groningen , The Netherlands
| | - Adriana Ilie
- Max-Planck-Institut für Kohlenforschung , Kaiser-Wilhelm-Platz 1 , 45470 Mülheim , Germany.,Department of Chemistry , Philipps-University , Hans-Meerwein-Strasse 4 , 35032 Marburg , Germany
| | - Marco W Fraaije
- Molecular Enzymology Group , University of Groningen , Nijenborgh 4 , 9747 AG Groningen , The Netherlands
| | - K N Houk
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
| | - Manfred T Reetz
- Max-Planck-Institut für Kohlenforschung , Kaiser-Wilhelm-Platz 1 , 45470 Mülheim , Germany.,Department of Chemistry , Philipps-University , Hans-Meerwein-Strasse 4 , 35032 Marburg , Germany
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33
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Lewis RD, Garcia-Borràs M, Chalkley MJ, Buller AR, Houk KN, Kan SBJ, Arnold FH. Catalytic iron-carbene intermediate revealed in a cytochrome c carbene transferase. Proc Natl Acad Sci U S A 2018; 115:7308-7313. [PMID: 29946033 PMCID: PMC6048479 DOI: 10.1073/pnas.1807027115] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recently, heme proteins have been discovered and engineered by directed evolution to catalyze chemical transformations that are biochemically unprecedented. Many of these nonnatural enzyme-catalyzed reactions are assumed to proceed through a catalytic iron porphyrin carbene (IPC) intermediate, although this intermediate has never been observed in a protein. Using crystallographic, spectroscopic, and computational methods, we have captured and studied a catalytic IPC intermediate in the active site of an enzyme derived from thermostable Rhodothermus marinus (Rma) cytochrome c High-resolution crystal structures and computational methods reveal how directed evolution created an active site for carbene transfer in an electron transfer protein and how the laboratory-evolved enzyme achieves perfect carbene transfer stereoselectivity by holding the catalytic IPC in a single orientation. We also discovered that the IPC in Rma cytochrome c has a singlet ground electronic state and that the protein environment uses geometrical constraints and noncovalent interactions to influence different IPC electronic states. This information helps us to understand the impressive reactivity and selectivity of carbene transfer enzymes and offers insights that will guide and inspire future engineering efforts.
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Affiliation(s)
- Russell D Lewis
- Division of Biology and Bioengineering, California Institute of Technology, Pasadena, CA 91125
| | - Marc Garcia-Borràs
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095
| | - Matthew J Chalkley
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Andrew R Buller
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095;
| | - S B Jennifer Kan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Frances H Arnold
- Division of Biology and Bioengineering, California Institute of Technology, Pasadena, CA 91125;
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
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34
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Mallinson SJB, Machovina MM, Silveira RL, Garcia-Borràs M, Gallup N, Johnson CW, Allen MD, Skaf MS, Crowley MF, Neidle EL, Houk KN, Beckham GT, DuBois JL, McGeehan JE. A promiscuous cytochrome P450 aromatic O-demethylase for lignin bioconversion. Nat Commun 2018; 9:2487. [PMID: 29950589 PMCID: PMC6021390 DOI: 10.1038/s41467-018-04878-2] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 05/26/2018] [Indexed: 11/18/2022] Open
Abstract
Microbial aromatic catabolism offers a promising approach to convert lignin, a vast source of renewable carbon, into useful products. Aryl-O-demethylation is an essential biochemical reaction to ultimately catabolize coniferyl and sinapyl lignin-derived aromatic compounds, and is often a key bottleneck for both native and engineered bioconversion pathways. Here, we report the comprehensive characterization of a promiscuous P450 aryl-O-demethylase, consisting of a cytochrome P450 protein from the family CYP255A (GcoA) and a three-domain reductase (GcoB) that together represent a new two-component P450 class. Though originally described as converting guaiacol to catechol, we show that this system efficiently demethylates both guaiacol and an unexpectedly wide variety of lignin-relevant monomers. Structural, biochemical, and computational studies of this novel two-component system elucidate the mechanism of its broad substrate specificity, presenting it as a new tool for a critical step in biological lignin conversion.
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Affiliation(s)
- Sam J B Mallinson
- Molecular Biophysics, School of Biological Sciences, Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth, PO1 2DY, UK
| | - Melodie M Machovina
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Rodrigo L Silveira
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
- Institute of Chemistry, University of Campinas, Campinas, Sao Paulo, 13083-970, Brazil
| | - Marc Garcia-Borràs
- Department of Chemistry and Biochemistry, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Nathan Gallup
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
- Department of Chemistry and Biochemistry, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Christopher W Johnson
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Mark D Allen
- Molecular Biophysics, School of Biological Sciences, Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth, PO1 2DY, UK
| | - Munir S Skaf
- Institute of Chemistry, University of Campinas, Campinas, Sao Paulo, 13083-970, Brazil
| | - Michael F Crowley
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Ellen L Neidle
- Department of Microbiology, University of Georgia, Athens, GA, 30602, USA
| | - Kendall N Houk
- Department of Chemistry and Biochemistry, University of California at Los Angeles, Los Angeles, CA, 90095, USA.
| | - Gregg T Beckham
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA.
| | - Jennifer L DuBois
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA.
| | - John E McGeehan
- Molecular Biophysics, School of Biological Sciences, Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth, PO1 2DY, UK.
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35
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El Bakouri O, Postils V, Garcia-Borràs M, Duran M, Luis JM, Calvello S, Soncini A, Matito E, Feixas F, Solà M. Metal Cluster Electrides: A New Type of Molecular Electride with Delocalised Polyattractor Character. Chemistry 2018; 24:9853-9859. [DOI: 10.1002/chem.201800878] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 04/16/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Ouissam El Bakouri
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química; Universitat de Girona; C/ Maria Aurèlia Capmany 69 17003 Girona Catalonia Spain
| | - Verònica Postils
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química; Universitat de Girona; C/ Maria Aurèlia Capmany 69 17003 Girona Catalonia Spain
| | - Marc Garcia-Borràs
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química; Universitat de Girona; C/ Maria Aurèlia Capmany 69 17003 Girona Catalonia Spain
- Department of Chemistry and Biochemistry; University of California; Los Angeles CA 90095 USA
| | - Miquel Duran
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química; Universitat de Girona; C/ Maria Aurèlia Capmany 69 17003 Girona Catalonia Spain
| | - Josep M. Luis
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química; Universitat de Girona; C/ Maria Aurèlia Capmany 69 17003 Girona Catalonia Spain
| | - Simone Calvello
- School of Chemistry; University of Melbourne; VIC 3010 Australia
| | | | - Eduard Matito
- Kimika Fakultatea; Euskal Herriko Unibertsitatea (UPV/EHU) and Donostia International Physics Center (DIPC); P.K. 1072 20080 Donostia Euskadi Spain
- Ikerbasque, Basque Foundation for Science; 48011 Bilbao Euskadi Spain
| | - Ferran Feixas
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química; Universitat de Girona; C/ Maria Aurèlia Capmany 69 17003 Girona Catalonia Spain
| | - Miquel Solà
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química; Universitat de Girona; C/ Maria Aurèlia Capmany 69 17003 Girona Catalonia Spain
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36
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Serrano-Hervás E, Casadevall G, Garcia-Borràs M, Feixas F, Osuna S. Epoxide Hydrolase Conformational Heterogeneity for the Resolution of Bulky Pharmacologically Relevant Epoxide Substrates. Chemistry 2018; 24:12254-12258. [DOI: 10.1002/chem.201801068] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Indexed: 01/22/2023]
Affiliation(s)
- Eila Serrano-Hervás
- Laboratori de Bioquímica Computacional (CompBioLab); Institut de Química Computacional i Catàlisi (IQCC); Departament de Química; Universitat de Girona (UdG); Carrer Maria Aurèlia Capmany 69 17003 Girona Spain
| | - Guillem Casadevall
- Laboratori de Bioquímica Computacional (CompBioLab); Institut de Química Computacional i Catàlisi (IQCC); Departament de Química; Universitat de Girona (UdG); Carrer Maria Aurèlia Capmany 69 17003 Girona Spain
| | - Marc Garcia-Borràs
- Department of Chemistry and Biochemistry; University of California, Los Angeles (UCLA); 607 Charles E. Young Drive Los Angeles CA 90095 USA
| | - Ferran Feixas
- Laboratori de Bioquímica Computacional (CompBioLab); Institut de Química Computacional i Catàlisi (IQCC); Departament de Química; Universitat de Girona (UdG); Carrer Maria Aurèlia Capmany 69 17003 Girona Spain
| | - Sílvia Osuna
- Laboratori de Bioquímica Computacional (CompBioLab); Institut de Química Computacional i Catàlisi (IQCC); Departament de Química; Universitat de Girona (UdG); Carrer Maria Aurèlia Capmany 69 17003 Girona Spain
- ICREA; Pg. Lluís Companys 23 08010 Barcelona Spain
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37
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Gao SS, Zhang T, Garcia-Borràs M, Hung YS, Billingsley JM, Houk KN, Hu Y, Tang Y. Biosynthesis of Heptacyclic Duclauxins Requires Extensive Redox Modifications of the Phenalenone Aromatic Polyketide. J Am Chem Soc 2018; 140:6991-6997. [PMID: 29741874 DOI: 10.1021/jacs.8b03705] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Duclauxins are dimeric and heptacyclic fungal polyketides with notable bioactivities. We characterized the cascade of redox transformations in the biosynthetic pathway of duclauxin from Talaromyces stipitatus. The redox reaction sequence is initiated by a cupin family dioxygenase DuxM that performs an oxidative cleavage of the peri-fused tricyclic phenalenone and affords a transient hemiketal-oxaphenalenone intermediate. Additional redox enzymes then morph the oxaphenoalenone into either an anhydride or a dihydrocoumarin-containing monomeric building block that is found in dimeric duxlauxins. Oxidative coupling between the monomers to form the initial C-C bond was shown to be catalyzed by a P450 monooxygenase, although the enzyme responsible for the second C-C bond formation was not found in the pathway. Collectively, the number and variety of redox enzymes used in the duclauxin pathway showcase Nature's strategy to generate structural complexity during natural product biosynthesis.
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Affiliation(s)
| | - Tao Zhang
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines , Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College , Beijing 100050 , China
| | | | | | | | | | - Youcai Hu
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines , Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College , Beijing 100050 , China
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38
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El Bakouri O, Garcia-Borràs M, Girón RM, Filippone S, Martín N, Solà M. On the regioselectivity of the Diels-Alder cycloaddition to C 60 in high spin states. Phys Chem Chem Phys 2018; 20:11577-11585. [PMID: 29417103 PMCID: PMC5932534 DOI: 10.1039/c7cp07965f] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 01/24/2018] [Indexed: 11/21/2022]
Abstract
Controlling the regioselectivity in the exohedral functionalization of fullerenes and endohedral metallofullerenes is essential to produce specific desired fullerene derivatives. In this work, using density functional theory (DFT) calculations, we show that the regioselectivity of the Diels-Alder (DA) cycloaddition of cyclopentadiene to 2S+1C60 changes from the usual [6,6] addition in the singlet ground state to the [5,6] attack in high spin states of C60. Changes in the aromaticity of the five- and six-membered rings when going from singlet to high spin C60 provide a rationale to understand this regioselectivity change. Experimentally, however, we find that the DA cycloaddition of isoindene to triplet C60 yields the usual [6,6] adduct. Further DFT calculations and computational analysis give an explanation to this unanticipated experimental result by showing the presence of an intersystem crossing close to the formed triplet biradical intermediate.
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Affiliation(s)
- Ouissam El Bakouri
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química , Universitat de Girona , c/Maria Aurèlia Capmany 6 , 17003 Girona , Spain .
| | - Marc Garcia-Borràs
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química , Universitat de Girona , c/Maria Aurèlia Capmany 6 , 17003 Girona , Spain .
- Department of Chemistry and Biochemistry , University of California , Los Angeles 607 Charles E Young Drive East , 90095 Los Angeles , CA , USA
| | - Rosa M. Girón
- Departamento de Química Orgánica , Facultad de Química , Universidad Complutense , Avda. Complutense s/n , E-28040 Madrid , Spain .
| | - Salvatore Filippone
- Departamento de Química Orgánica , Facultad de Química , Universidad Complutense , Avda. Complutense s/n , E-28040 Madrid , Spain .
| | - Nazario Martín
- Departamento de Química Orgánica , Facultad de Química , Universidad Complutense , Avda. Complutense s/n , E-28040 Madrid , Spain .
- IMDEA–Nanociencia , C/Faraday, 9 , Campus de Cantoblanco , E-28049 Madrid , Spain
| | - Miquel Solà
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química , Universitat de Girona , c/Maria Aurèlia Capmany 6 , 17003 Girona , Spain .
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39
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Newmister SA, Li S, Garcia-Borràs M, Sanders JN, Yang S, Lowell AN, Yu F, Smith JL, Williams RM, Houk KN, Sherman DH. Structural basis of the Cope rearrangement and cyclization in hapalindole biogenesis. Nat Chem Biol 2018. [PMID: 29531360 DOI: 10.1038/s41589-018-0003-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Hapalindole alkaloids are a structurally diverse class of cyanobacterial natural products defined by their varied polycyclic ring systems and diverse biological activities. These complex metabolites are generated from a common biosynthetic intermediate by the Stig cyclases in three mechanistic steps: a rare Cope rearrangement, 6-exo-trig cyclization, and electrophilic aromatic substitution. Here we report the structure of HpiC1, a Stig cyclase that catalyzes the formation of 12-epi-hapalindole U in vitro. The 1.5-Å structure revealed a dimeric assembly with two calcium ions per monomer and with the active sites located at the distal ends of the protein dimer. Mutational analysis and computational methods uncovered key residues for an acid-catalyzed [3,3]-sigmatropic rearrangement, as well as specific determinants that control the position of terminal electrophilic aromatic substitution, leading to a switch from hapalindole to fischerindole alkaloids.
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Affiliation(s)
- Sean A Newmister
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Shasha Li
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA.,Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Marc Garcia-Borràs
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - Jacob N Sanders
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - Song Yang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - Andrew N Lowell
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Fengan Yu
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Janet L Smith
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA.,Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Robert M Williams
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA. .,University of Colorado Cancer Center, Aurora, CO, USA.
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA.
| | - David H Sherman
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA. .,Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI, USA. .,Department of Chemistry, University of Michigan, Ann Arbor, MI, USA. .,Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA.
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40
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Vidal S, Izquierdo M, Alom S, Garcia-Borràs M, Filippone S, Osuna S, Solà M, Whitby RJ, Martín N. Effect of incarcerated HF on the exohedral chemical reactivity of HF@C 60. Chem Commun (Camb) 2018; 53:10993-10996. [PMID: 28835947 DOI: 10.1039/c7cc05987f] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The first chemical modification on the brand new endohedral HF@C60 is reported. In particular, the isomerization from optically pure (2S,5S)-cis-pyrrolidino[3,4:1,2][60]fullerene 2b to (2S,5R)-trans-pyrrolidino[3,4:1,2][60]fullerene 2b has been studied and compared with empty C60 (2a) and endohedral H2O@C60 (3). The comparative study shows a kinetic order for the isomerization process of H2O@C60 > HF@C60 > C60, thus confirming the effect of the incarcerated species on the zwitterionic intermediate stability.
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Affiliation(s)
- Sara Vidal
- Dep. Química Orgánica I, UCM, Avda. Complutense s/n, E-28040 Madrid, Spain.
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41
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Serrano-Hervás E, Garcia-Borràs M, Osuna S. Exploring the origins of selectivity in soluble epoxide hydrolase from Bacillus megaterium. Org Biomol Chem 2018; 15:8827-8835. [PMID: 29026902 PMCID: PMC5708342 DOI: 10.1039/c7ob01847a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Epoxide hydrolase (EH) enzymes catalyze the hydration of racemic epoxides to yield their corresponding vicinal diols. In this work, the Bacillus megaterium epoxide hydrolase (BmEH)-mediated hydrolysis of racemic styrene oxide (rac-SO) and its para-nitro styrene oxide (rac-p-NSO) derivative are computationally investigated using density functional theory (DFT).
Epoxide hydrolase (EH) enzymes catalyze the hydration of racemic epoxides to yield their corresponding vicinal diols. These enzymes present different enantio- and regioselectivity depending upon either the substrate structure or the substitution pattern of the epoxide ring. In this study, we computationally investigate the Bacillus megaterium epoxide hydrolase (BmEH)-mediated hydrolysis of racemic styrene oxide (rac-SO) and its para-nitro styrene oxide (rac-p-NSO) derivative using density functional theory (DFT) and an active site cluster model consisting of 195 and 197 atoms, respectively. Full reaction mechanisms for epoxide ring opening were evaluated considering the attack at both oxirane carbons and considering two possible orientations of the substrate at the BmEH active site. Our results indicate that for both SO and p-NSO substrates the BmEH enantio- and regioselectivity is opposite to the inherent (R)-BmEH selectivity, the attack at the benzylic position (C1) of the (S)-enantiomer being the most favoured chemical outcome.
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Affiliation(s)
- Eila Serrano-Hervás
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Carrer Maria Aurèlia Capmany 69, 17003 Girona, Spain.
| | - Marc Garcia-Borràs
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, CA 90095, USA.
| | - Sílvia Osuna
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Carrer Maria Aurèlia Capmany 69, 17003 Girona, Spain.
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42
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Romero-Rivera A, Garcia-Borràs M, Osuna S. Role of Conformational Dynamics in the Evolution of Retro-Aldolase Activity. ACS Catal 2017; 7:8524-8532. [PMID: 29226011 PMCID: PMC5716449 DOI: 10.1021/acscatal.7b02954] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 10/19/2017] [Indexed: 12/19/2022]
Abstract
![]()
Enzymes exist as
ensembles of conformations that are important
for function. Tuning these populations of conformational states through
mutation enables evolution toward additional activities. Here we computationally
evaluate the population shifts induced by distal and active site mutations
in a family of computationally designed and experimentally optimized
retro-aldolases. The conformational landscape of these enzymes was
significantly altered during evolution, as pre-existing catalytically
active conformational substates became major states in the most evolved
variants. We further demonstrate that key residues responsible for
these substate conversions can be predicted computationally. Significantly,
the identified residues coincide with those positions mutated in the
laboratory evolution experiments. This study establishes that distal
mutations that affect enzyme catalytic activity can be predicted computationally
and thus provides the enzyme (re)design field with a rational strategy
to determine promising sites for enhancing activity through mutation.
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Affiliation(s)
- Adrian Romero-Rivera
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Carrer Maria Aurèlia Capmany 69, 17003 Girona, Spain
| | - Marc Garcia-Borràs
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Carrer Maria Aurèlia Capmany 69, 17003 Girona, Spain
- Department of Chemistry and Biochemistry, University of California, Los Angeles (UCLA), 607 Charles E. Young Drive, Los Angeles, California 90095, United States
| | - Sílvia Osuna
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Carrer Maria Aurèlia Capmany 69, 17003 Girona, Spain
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Abstract
The computational design of enzymes is a tremendous challenge for both chemistry and biochemistry. The ability to design stable and functional biocatalysts that could operate under different conditions to perform chemical reactions without precedent in nature, allowing the large-scale production of chemicals à la carte, would revolutionise both synthetic, pharmacologic and materials chemistry. Despite the great advances achieved, this highly multidisciplinary area of research is still in its infancy. This chapter describes the ‘inside-out’ protocol for computational enzyme design and both the achievements and limitations of the current technology are highlighted. Furthermore, molecular dynamics simulations have proved to be invaluable in the enzyme design process, constituting an important tool for discovering elusive catalytically relevant conformations of the engineered or designed enzyme. As a complement to the ‘inside-out’ design protocol, different examples where hybrid QM/MM approaches have been directly applied to discover beneficial mutations in rational computational enzyme design are described.
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Affiliation(s)
- Marc Garcia-Borràs
- Department of Chemistry and Biochemistry, University of California Los Angeles California CA 90095-1569 USA
| | - Kendall N. Houk
- Department of Chemistry and Biochemistry, University of California Los Angeles California CA 90095-1569 USA
| | - Gonzalo Jiménez-Osés
- Departamento de Química, Centro de Investigación en Síntesis Química Universidad de La Rioja 26006 Logroño La Rioja Spain
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44
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Fraley AE, Garcia-Borràs M, Tripathi A, Khare D, Mercado-Marin EV, Tran H, Dan Q, Webb GP, Watts KR, Crews P, Sarpong R, Williams RM, Smith JL, Houk KN, Sherman DH. Function and Structure of MalA/MalA', Iterative Halogenases for Late-Stage C-H Functionalization of Indole Alkaloids. J Am Chem Soc 2017; 139:12060-12068. [PMID: 28777910 PMCID: PMC5595095 DOI: 10.1021/jacs.7b06773] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Malbrancheamide is a dichlorinated fungal indole alkaloid isolated from both Malbranchea aurantiaca and Malbranchea graminicola that belongs to a family of natural products containing a characteristic bicyclo[2.2.2]diazaoctane core. The introduction of chlorine atoms on the indole ring of malbrancheamide differentiates it from other members of this family and contributes significantly to its biological activity. In this study, we characterized the two flavin-dependent halogenases involved in the late-stage halogenation of malbrancheamide in two different fungal strains. MalA and MalA' catalyze the iterative dichlorination and monobromination of the free substrate premalbrancheamide as the final steps in the malbrancheamide biosynthetic pathway. Two unnatural bromo-chloro-malbrancheamide analogues were generated through MalA-mediated chemoenzymatic synthesis. Structural analysis and computational studies of MalA' in complex with three substrates revealed that the enzyme represents a new class of zinc-binding flavin-dependent halogenases and provides new insights into a potentially unique reaction mechanism.
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Affiliation(s)
- Amy E. Fraley
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Marc Garcia-Borràs
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Ashootosh Tripathi
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Dheeraj Khare
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | | | - Hong Tran
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Qingyun Dan
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Gabrielle P. Webb
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Katharine R. Watts
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, United States
| | - Phillip Crews
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, United States
| | - Richmond Sarpong
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Robert M. Williams
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Janet L. Smith
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - K. N. Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - David H. Sherman
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan 48109, United States
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45
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Garcia-Borràs M, Osuna S, Luis JM, Solà M. Rationalizing the relative abundances of trimetallic nitride template-based endohedral metallofullerenes from aromaticity measures. Chem Commun (Camb) 2017; 53:4140-4143. [PMID: 28352903 PMCID: PMC5436040 DOI: 10.1039/c7cc01750b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 03/20/2017] [Indexed: 11/25/2022]
Abstract
The synthesis of endohedral metallofullerenes (EMFs) from a carbon soot sample of an arc discharge leads to a variety of EMFs that are obtained in different relative abundances. In the present work, we show that these abundances can be predicted from aromaticity calculations. In particular, we use the normalized Additive Local Aromaticity (ALAN) index. Our results show that the most abundant Sc3N-based and Y3N-based EMFs in fullerene soot are the most aromatic. This study reinforces the idea that aromaticity plays a key role in determining the stability of EMFs.
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Affiliation(s)
- M Garcia-Borràs
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA. and Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, 17003 Girona, Catalonia, Spain.
| | - S Osuna
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, 17003 Girona, Catalonia, Spain.
| | - J M Luis
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, 17003 Girona, Catalonia, Spain.
| | - M Solà
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, 17003 Girona, Catalonia, Spain.
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46
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Gao SS, Garcia-Borràs M, Barber JS, Hai Y, Duan A, Garg NK, Houk KN, Tang Y. Enzyme-Catalyzed Intramolecular Enantioselective Hydroalkoxylation. J Am Chem Soc 2017; 139:3639-3642. [PMID: 28240554 DOI: 10.1021/jacs.7b01089] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Hydroalkoxylation is a powerful and efficient method of forming C-O bonds and cyclic ethers in synthetic chemistry. In studying the biosynthesis of the fungal natural product herqueinone, we identified an enzyme that can perform an intramolecular enantioselective hydroalkoxylation reaction. PhnH catalyzes the addition of a phenol to the terminal olefin of a reverse prenyl group to give a dihydrobenzofuran product. The enzyme accelerates the reaction by 3 × 105-fold compared to the uncatalyzed reaction. PhnH belongs to a superfamily of proteins with a domain of unknown function (DUF3237), of which no member has a previously verified function. The discovery of PhnH demonstrates that enzymes can be used to promote the enantioselective hydroalkoxylation reaction and form cyclic ethers.
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Affiliation(s)
- Shu-Shan Gao
- Department of Chemical and Biomolecular Engineering and ⊥Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
| | - Marc Garcia-Borràs
- Department of Chemical and Biomolecular Engineering and ⊥Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
| | - Joyann S Barber
- Department of Chemical and Biomolecular Engineering and ⊥Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
| | - Yang Hai
- Department of Chemical and Biomolecular Engineering and ⊥Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
| | - Abing Duan
- Department of Chemical and Biomolecular Engineering and ⊥Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
| | - Neil K Garg
- Department of Chemical and Biomolecular Engineering and ⊥Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
| | - K N Houk
- Department of Chemical and Biomolecular Engineering and ⊥Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
| | - Yi Tang
- Department of Chemical and Biomolecular Engineering and ⊥Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
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Romero-Rivera A, Garcia-Borràs M, Osuna S. Computational tools for the evaluation of laboratory-engineered biocatalysts. Chem Commun (Camb) 2016; 53:284-297. [PMID: 27812570 PMCID: PMC5310519 DOI: 10.1039/c6cc06055b] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 09/06/2016] [Indexed: 12/18/2022]
Abstract
Biocatalysis is based on the application of natural catalysts for new purposes, for which enzymes were not designed. Although the first examples of biocatalysis were reported more than a century ago, biocatalysis was revolutionized after the discovery of an in vitro version of Darwinian evolution called Directed Evolution (DE). Despite the recent advances in the field, major challenges remain to be addressed. Currently, the best experimental approach consists of creating multiple mutations simultaneously while limiting the choices using statistical methods. Still, tens of thousands of variants need to be tested experimentally, and little information is available on how these mutations lead to enhanced enzyme proficiency. This review aims to provide a brief description of the available computational techniques to unveil the molecular basis of improved catalysis achieved by DE. An overview of the strengths and weaknesses of current computational strategies is explored with some recent representative examples. The understanding of how this powerful technique is able to obtain highly active variants is important for the future development of more robust computational methods to predict amino-acid changes needed for activity.
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Affiliation(s)
- Adrian Romero-Rivera
- Institut de Química Computacional i Catàlisi and Departament de Química Universitat de Girona, Campus Montilivi, 17071 Girona, Catalonia, Spain.
| | - Marc Garcia-Borràs
- Department of Chemistry and Biochemistry, University of California, 607 Charles E. Young Drive, Los Angeles, California 90095, USA
| | - Sílvia Osuna
- Institut de Química Computacional i Catàlisi and Departament de Química Universitat de Girona, Campus Montilivi, 17071 Girona, Catalonia, Spain.
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48
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Li Y, Osuna S, Garcia-Borràs M, Qi X, Liu S, Houk KN, Lan Y. Reactivity of Single-Walled Carbon Nanotubes in the Diels-Alder Cycloaddition Reaction: Distortion-Interaction Analysis along the Reaction Pathway. Chemistry 2016; 22:12819-24. [PMID: 27465519 DOI: 10.1002/chem.201601799] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2016] [Indexed: 11/06/2022]
Abstract
Diels-Alder cycloaddition is one of the most powerful tools for the functionalization of single-walled carbon nanotubes (SWCNTs). Density functional theory at the B3-LYP level of theory has been used to investigate the reactivity of different-diameter SWCNTs (4-9,5) in Diels-Alder reactions with 1,3-butadiene; the reactivity was found to decrease with increasing SWCNT diameter. Distortion/interaction analysis along the whole reaction pathway was found to be a better way to explore the reactivity of this type of reaction. The difference in interaction energy along the reaction pathway is larger than that of the corresponding distortion energy. However, the distortion energy plots for these reactions show the same trend. Therefore, the formation of the transition state can be determined from the interaction energy. A lower interaction energy leads to an earlier transition state, which indicates a lower activation energy. The computational results also indicate that the original distortion of the SWCNTs leads to an increase in the reactivity of the SWCNTs.
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Affiliation(s)
- Yingzi Li
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, 400030, P. R. China
| | - Sílvia Osuna
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095-1569, USA
| | - Marc Garcia-Borràs
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095-1569, USA
| | - Xiaotian Qi
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, 400030, P. R. China
| | - Song Liu
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, 400030, P. R. China
| | - Kendall N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095-1569, USA.
| | - Yu Lan
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, 400030, P. R. China.
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Zaleśny R, Garcia-Borràs M, Góra RW, Medved' M, Luis JM. On the physical origins of interaction-induced vibrational (hyper)polarizabilities. Phys Chem Chem Phys 2016; 18:22467-77. [PMID: 27465257 DOI: 10.1039/c6cp02500e] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This paper presents the results of a pioneering exploration of the physical origins of vibrational contributions to the interaction-induced electric properties of molecular complexes. In order to analyze the excess nuclear relaxation (hyper)polarizabilities, a new scheme was proposed which relies on the computationally efficient Bishop-Hasan-Kirtman method for determining the nuclear relaxation contributions to electric properties. The extension presented herein is general and can be used with any interaction-energy partitioning method. As an example, in this study we employed the variational-perturbational interaction-energy decomposition scheme (at the MP2/aug-cc-pVQZ level) and the extended transition state method by employing three exchange-correlation functionals (BLYP, LC-BLYP, and LC-BLYP-dDsC) to study the excess properties of the HCN dimer. It was observed that the first-order electrostatic contribution to the excess nuclear relaxation polarizability cancels with the negative exchange repulsion term out to a large extent, resulting in a positive value of Δα(nr) due to the contributions from the delocalization and the dispersion terms. In the case of the excess nuclear relaxation first hyperpolarizability, the pattern of interaction contributions is very similar to that for Δα(nr), both in terms of their sign as well as relative magnitude. Finally, our results show that the LC-BLYP and LC-BLYP-dDsC functionals, which yield smaller values of the orbital relaxation term than BLYP, are more successful in predicting excess properties.
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Affiliation(s)
- Robert Zaleśny
- Department of Physical and Quantum Chemistry, Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland.
| | - Marc Garcia-Borràs
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA
| | - Robert W Góra
- Department of Physical and Quantum Chemistry, Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland.
| | - Miroslav Medved'
- Department of Chemistry, Faculty of Natural Sciences, Matej Bel University, Tajovského 40, SK-97400 Banská Bystrica, Slovak Republic
| | - Josep M Luis
- Institute of Computational Chemistry and Catalysis and Department of Chemistry, University of Girona, Campus de Montilivi, 17071 Girona, Catalonia, Spain.
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Martínez JP, Garcia-Borràs M, Osuna S, Poater J, Bickelhaupt FM, Solà M. Reaction Mechanism and Regioselectivity of the Bingel-Hirsch Addition of Dimethyl Bromomalonate to La@C2v -C82. Chemistry 2016; 22:5953-62. [PMID: 26991842 DOI: 10.1002/chem.201504668] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Indexed: 11/09/2022]
Abstract
We quantum chemically explore the thermodynamics and kinetics of all 65 possible mechanistic pathways of the Bingel-Hirsch addition of dimethyl bromomalonate to the endohedral metallofullerene La@C2v -C82 that result from the combination of 24 nonequivalent carbon atoms and 35 different bonds present in La@C2v -C82 by using dispersion-corrected DFT calculations. Experimentally, this reaction leads to four singly bonded derivatives and one fulleroid adduct. Of these five products, only the singly bonded derivative on C23 could be experimentally identified unambiguously. Our calculations show that La@C2v -C82 is not particularly regioselective under Bingel-Hirsch conditions. From the obtained results, however, it is possible to make a tentative assignment of the products observed experimentally. We propose that the observed fulleroid adduct results from the attack at bond 19 and that the singly bonded derivatives correspond to the C2, C19, C21, and C23 initial attacks. However, other possibilities cannot be ruled out completely.
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Affiliation(s)
- Juan Pablo Martínez
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, Campus de Montilivi, 17071, Girona, Catalonia, Spain
| | - Marc Garcia-Borràs
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, Campus de Montilivi, 17071, Girona, Catalonia, Spain
| | - Sílvia Osuna
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, Campus de Montilivi, 17071, Girona, Catalonia, Spain
| | - Jordi Poater
- Department of Theoretical Chemistry and Amsterdam Center for Multiscale Modeling, Vrije Universiteit Amsterdam, De Boeleaan 1083, 1081 HV, Amsterdam, The Netherlands.,Departament de Química Orgànica & IQTCUB, Universitat de Barcelona, Martí i Franquès 1-11, 08028, Barcelona, Catalonia, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, 08010, Barcelona, Catalonia, Spain
| | - F Matthias Bickelhaupt
- Department of Theoretical Chemistry and Amsterdam Center for Multiscale Modeling, Vrije Universiteit Amsterdam, De Boeleaan 1083, 1081 HV, Amsterdam, The Netherlands. .,Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands.
| | - Miquel Solà
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, Campus de Montilivi, 17071, Girona, Catalonia, Spain.
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