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Merging enzymes with chemocatalysis for amide bond synthesis. Nat Commun 2022; 13:380. [PMID: 35046426 PMCID: PMC8770729 DOI: 10.1038/s41467-022-28005-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 12/16/2021] [Indexed: 01/03/2023] Open
Abstract
Amides are one of the most fundamental chemical bonds in nature. In addition to proteins and other metabolites, many valuable synthetic products comprise amide bonds. Despite this, there is a need for more sustainable amide synthesis. Herein, we report an integrated next generation multi-catalytic system, merging nitrile hydratase enzymes with a Cu-catalysed N-arylation reaction in a single reaction vessel, for the construction of ubiquitous amide bonds. This synergistic one-pot combination of chemo- and biocatalysis provides an amide bond disconnection to precursors, that are orthogonal to those in classical amide synthesis, obviating the need for protecting groups and delivering amides in a manner unachievable using existing catalytic regimes. Our integrated approach also affords broad scope, very high (molar) substrate loading, and has excellent functional group tolerance, telescoping routes to natural product derivatives, drug molecules, and challenging chiral amides under environmentally friendly conditions at scale. Proteins, other metabolites and many valuable synthetic products contain amide bonds and there is a need for more sustainable amide synthesis routes. Here the authors show an integrated next generation multi-catalytic system, merging nitrile hydratase enzymes with a Cu-catalysed N-arylation reaction in a single reaction vessel, for the construction of ubiquitous amide bonds.
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Abstract
The active pharmaceutical ingredient levetiracetam has anticonvulsant properties and is used to treat epilepsies. Herein, we describe the enantioselective preparation of the levetiracetam precursor 2-(pyrrolidine-1-yl)butanamide by enzymatic dynamic kinetic resolution with a nitrile hydratase enzyme. A rare representative of the family of iron-dependent nitrile hydratases from Gordonia hydrophobica (GhNHase) was evaluated for its potential to form 2-(pyrrolidine-1-yl)butanamide in enantioenriched form from the three small, simple molecules, namely, propanal, pyrrolidine and cyanide. The yield and the enantiomeric excess (ee) of the product are determined most significantly by the substrate concentrations, the reaction pH and the biocatalyst amount. GhNHase is also active for the hydration of other nitriles, in particular for the formation of N-heterocyclic amides such as nicotinamide, and may therefore be a tool for the preparation of various APIs.
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3
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Grill B, Glänzer M, Schwab H, Steiner K, Pienaar D, Brady D, Donsbach K, Winkler M. Functional Expression and Characterization of a Panel of Cobalt and Iron-Dependent Nitrile Hydratases. Molecules 2020; 25:molecules25112521. [PMID: 32481666 PMCID: PMC7321127 DOI: 10.3390/molecules25112521] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 05/25/2020] [Accepted: 05/26/2020] [Indexed: 11/16/2022] Open
Abstract
Nitrile hydratases (NHase) catalyze the hydration of nitriles to the corresponding amides. We report on the heterologous expression of various nitrile hydratases. Some of these enzymes have been investigated by others and us before, but sixteen target proteins represent novel sequences. Of 21 target sequences, 4 iron and 16 cobalt containing proteins were functionally expressed from Escherichia coli BL21 (DE3) Gold. Cell free extracts were used for activity profiling and basic characterization of the NHases using the typical NHase substrate methacrylonitrile. Co-type NHases are more tolerant to high pH than Fe-type NHases. A screening for activity on three structurally diverse nitriles was carried out. Two novel Co-dependent NHases from Afipia broomeae and Roseobacter sp. and a new Fe-type NHase from Gordonia hydrophobica were very well expressed and hydrated methacrylonitrile, pyrazine-carbonitrile, and 3-amino-3-(p-toluoyl)propanenitrile. The Co-dependent NHases from Caballeronia jiangsuensis and Microvirga lotononidis, as well as two Fe-dependent NHases from Pseudomonades, were—in addition—able to produce the amide from cinnamonitrile. Summarizing, seven so far uncharacterized NHases are described to be promising biocatalysts.
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Affiliation(s)
- Birgit Grill
- Austrian Center of Industrial Biotechnology GmbH, 8010 Graz, Austria; (B.G.); (M.G.); (H.S.); (K.S.)
| | - Maximilian Glänzer
- Austrian Center of Industrial Biotechnology GmbH, 8010 Graz, Austria; (B.G.); (M.G.); (H.S.); (K.S.)
| | - Helmut Schwab
- Austrian Center of Industrial Biotechnology GmbH, 8010 Graz, Austria; (B.G.); (M.G.); (H.S.); (K.S.)
| | - Kerstin Steiner
- Austrian Center of Industrial Biotechnology GmbH, 8010 Graz, Austria; (B.G.); (M.G.); (H.S.); (K.S.)
| | - Daniel Pienaar
- Molecular Science Institute, School of Chemistry, University of the Witwatersrand, P.O. Wits 2050, Johannesburg, South Africa; (D.P.); (D.B.)
| | - Dean Brady
- Molecular Science Institute, School of Chemistry, University of the Witwatersrand, P.O. Wits 2050, Johannesburg, South Africa; (D.P.); (D.B.)
| | | | - Margit Winkler
- Austrian Center of Industrial Biotechnology GmbH, 8010 Graz, Austria; (B.G.); (M.G.); (H.S.); (K.S.)
- Institute of Molecular Biotechnology, Graz University of Technology, NAWI Graz, 8010 Graz, Austria
- Correspondence: ; Tel.: +43-316-873-9333
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Cheng Z, Xia Y, Zhou Z. Recent Advances and Promises in Nitrile Hydratase: From Mechanism to Industrial Applications. Front Bioeng Biotechnol 2020; 8:352. [PMID: 32391348 PMCID: PMC7193024 DOI: 10.3389/fbioe.2020.00352] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 03/30/2020] [Indexed: 12/21/2022] Open
Abstract
Nitrile hydratase (NHase, EC 4.2.1.84) is one type of metalloenzyme participating in the biotransformation of nitriles into amides. Given its catalytic specificity in amide production and eco-friendliness, NHase has overwhelmed its chemical counterpart during the past few decades. However, unclear catalytic mechanism, low thermostablity, and narrow substrate specificity limit the further application of NHase. During the past few years, numerous studies on the theoretical and industrial aspects of NHase have advanced the development of this green catalyst. This review critically focuses on NHase research from recent years, including the natural distribution, gene types, posttranslational modifications, expression, proposed catalytic mechanism, biochemical properties, and potential applications of NHase. The developments of NHase described here are not only useful for further application of NHase, but also beneficial for the development of the fields of biocatalysis and biotransformation.
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Affiliation(s)
| | | | - Zhemin Zhou
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
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5
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Wang C, Bai X, Wang R, Zheng X, Ma X, Chen H, Ai Y, Bai Y, Liu Y. Synthesis of Imatinib by C–N Coupling Reaction of Primary Amide and Bromo-Substituted Pyrimidine Amine. Org Process Res Dev 2019. [DOI: 10.1021/acs.oprd.9b00227] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Cuiling Wang
- College of Life Sciences, Northwest University, Xi’an 710069, China
| | - Xiao Bai
- College of Life Sciences, Northwest University, Xi’an 710069, China
| | - Rui Wang
- College of Life Sciences, Northwest University, Xi’an 710069, China
| | - Xudong Zheng
- College of Life Sciences, Northwest University, Xi’an 710069, China
| | - Xiumei Ma
- College of Life Sciences, Northwest University, Xi’an 710069, China
| | - Huan Chen
- College of Life Sciences, Northwest University, Xi’an 710069, China
| | - Yun Ai
- College of Life Sciences, Northwest University, Xi’an 710069, China
- Xi’an Institute for Food and Drug Control, Xi’an 710054, China
| | - Yajun Bai
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, College of Chemistry & Materials Science, Northwest University, Xi’an 710127, China
| | - Yifeng Liu
- Applied Chemical Institute, Northwest University, Xi’an 710069, China
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Cheng Z, Peplowski L, Cui W, Xia Y, Liu Z, Zhang J, Kobayashi M, Zhou Z. Identification of key residues modulating the stereoselectivity of nitrile hydratase toward rac-mandelonitrile by semi-rational engineering. Biotechnol Bioeng 2017; 115:524-535. [DOI: 10.1002/bit.26484] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 10/19/2017] [Accepted: 10/22/2017] [Indexed: 01/20/2023]
Affiliation(s)
- Zhongyi Cheng
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology; Jiangnan University; Wuxi China
| | - Lukasz Peplowski
- Faculty of Physics; Institute of Physics; Astronomy and Informatics; Nicolaus. Copernicus University; Grudziadzka 5 Torun Poland
| | - Wenjing Cui
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology; Jiangnan University; Wuxi China
| | - Yuanyuan Xia
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology; Jiangnan University; Wuxi China
| | - Zhongmei Liu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology; Jiangnan University; Wuxi China
| | - Jialei Zhang
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology; Jiangnan University; Wuxi China
| | - Michihiko Kobayashi
- Institute of Applied Biochemistry and the Graduate School of Life and Environmental Sciences; The University of Tsukuba; Tsukuba Ibaraki Japan
| | - Zhemin Zhou
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology; Jiangnan University; Wuxi China
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7
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Hönig M, Sondermann P, Turner NJ, Carreira EM. Enantioselective Chemo- and Biocatalysis: Partners in Retrosynthesis. Angew Chem Int Ed Engl 2017; 56:8942-8973. [DOI: 10.1002/anie.201612462] [Citation(s) in RCA: 194] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Indexed: 01/08/2023]
Affiliation(s)
- Moritz Hönig
- Laboratorium für Organische Chemie; Eidgenössische Technische Hochschule Zürich; Vladimir-Prelog-Weg 3 8093 Zürich Switzerland
| | - Philipp Sondermann
- Laboratorium für Organische Chemie; Eidgenössische Technische Hochschule Zürich; Vladimir-Prelog-Weg 3 8093 Zürich Switzerland
| | - Nicholas J. Turner
- Manchester Institute of Biotechnology & School of Chemistry; University of Manchester; 131 Princess Street Manchester M1 7DN UK
| | - Erick M. Carreira
- Laboratorium für Organische Chemie; Eidgenössische Technische Hochschule Zürich; Vladimir-Prelog-Weg 3 8093 Zürich Switzerland
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8
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Hönig M, Sondermann P, Turner NJ, Carreira EM. Enantioselektive Chemo- und Biokatalyse: Partner in der Retrosynthese. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201612462] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Moritz Hönig
- Laboratorium für Organische Chemie; Eidgenössische Technische Hochschule Zürich; Vladimir-Prelog-Weg 3 8093 Zürich Schweiz
| | - Philipp Sondermann
- Laboratorium für Organische Chemie; Eidgenössische Technische Hochschule Zürich; Vladimir-Prelog-Weg 3 8093 Zürich Schweiz
| | - Nicholas J. Turner
- Manchester Institute of Biotechnology & School of Chemistry; University of Manchester; 131 Princess Street Manchester M1 7DN UK
| | - Erick M. Carreira
- Laboratorium für Organische Chemie; Eidgenössische Technische Hochschule Zürich; Vladimir-Prelog-Weg 3 8093 Zürich Schweiz
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9
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Wilding B, Veselá AB, Perry JJB, Black GW, Zhang M, Martínková L, Klempier N. An investigation of nitrile transforming enzymes in the chemo-enzymatic synthesis of the taxol sidechain. Org Biomol Chem 2016; 13:7803-12. [PMID: 26107443 DOI: 10.1039/c5ob01191d] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Paclitaxel (taxol) is an antimicrotubule agent widely used in the treatment of cancer. Taxol is prepared in a semisynthetic route by coupling the N-benzoyl-(2R,3S)-3-phenylisoserine sidechain to the baccatin III core structure. Precursors of the taxol sidechain have previously been prepared in chemoenzymatic approaches using acylases, lipases, and reductases, mostly featuring the enantioselective, enzymatic step early in the reaction pathway. Here, nitrile hydrolysing enzymes, namely nitrile hydratases and nitrilases, are investigated for the enzymatic hydrolysis of two different sidechain precursors. Both sidechain precursors, an openchain α-hydroxy-β-amino nitrile and a cyanodihydrooxazole, are suitable for coupling to baccatin III directly after the enzymatic step. An extensive set of nitrilases and nitrile hydratases was screened towards their activity and selectivity in the hydrolysis of two taxol sidechain precursors and their epimers. A number of nitrilases and nitrile hydratases converted both sidechain precursors and their epimers.
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Affiliation(s)
- Birgit Wilding
- acib GmbH (Austrian Centre of Industrial Biotechnology), c/o Institute of Organic Chemistry, Graz University of Technology, Stremayrgasse 9, A-8010 Graz, Austria.
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van Rantwijk F, Stolz A. Enzymatic cascade synthesis of (S)-2-hydroxycarboxylic amides and acids: Cascade reactions employing a hydroxynitrile lyase, nitrile-converting enzymes and an amidase. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.molcatb.2014.08.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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11
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Angelini LML, da Silva ARM, Rocco LDFC, Milagre CDDF. A high-throughput screening assay for distinguishing nitrile hydratases from nitrilases. Braz J Microbiol 2015. [PMID: 26221095 PMCID: PMC4512080 DOI: 10.1590/s1517-838246120130851] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
A modified colorimetric high-throughput screen based on pH changes combined with an amidase inhibitor capable of distinguishing between nitrilases and nitrile hydratases. This enzymatic screening is based on a binary response and is suitable for the first step of hierarchical screening projects.
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Affiliation(s)
- Leticia Mara Lima Angelini
- Instituto de of Biociências, Universidade Estadual Paulista "Julio de Mesquita Filho", Rio Claro, SP, Brazil
| | | | - Lucas de Freitas Coli Rocco
- Instituto de of Biociências, Universidade Estadual Paulista "Julio de Mesquita Filho", Rio Claro, SP, Brazil
| | - Cintia Duarte de Freitas Milagre
- Departamento de Química Orgânia, Instituto de Química, Universidade Estadual Paulista "Julio de Mesquita Filho", Araraquara, SP, Brazil
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12
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Black GW, Brown NL, Perry JJB, Randall PD, Turnbull G, Zhang M. A high-throughput screening method for determining the substrate scope of nitrilases. Chem Commun (Camb) 2015; 51:2660-2. [DOI: 10.1039/c4cc06021k] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have developed a chromogenic reagent to show nitrilase activity and demonstrate its use with 23 enzymes as cell-free extracts.
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Affiliation(s)
- Gary W. Black
- Industrial Biotechnology Research Group
- Department of Applied Sciences
- Faculty of Health and Life Sciences
- Northumbria University
- Newcastle upon Tyne
| | - Nicola L. Brown
- Industrial Biotechnology Research Group
- Department of Applied Sciences
- Faculty of Health and Life Sciences
- Northumbria University
- Newcastle upon Tyne
| | - Justin J. B. Perry
- Industrial Biotechnology Research Group
- Department of Applied Sciences
- Faculty of Health and Life Sciences
- Northumbria University
- Newcastle upon Tyne
| | | | - Graeme Turnbull
- Industrial Biotechnology Research Group
- Department of Applied Sciences
- Faculty of Health and Life Sciences
- Northumbria University
- Newcastle upon Tyne
| | - Meng Zhang
- Industrial Biotechnology Research Group
- Department of Applied Sciences
- Faculty of Health and Life Sciences
- Northumbria University
- Newcastle upon Tyne
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13
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Leighty MW, Shen B, Johnston JN. Enantioselective synthesis of α-oxy amides via Umpolung amide synthesis. J Am Chem Soc 2012; 134:15233-6. [PMID: 22967461 PMCID: PMC3477818 DOI: 10.1021/ja306225u] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
α-Oxy amides are prepared through enantioselective synthesis using a sequence beginning with a Henry addition of bromonitromethane to aldehydes and finishing with Umpolung Amide Synthesis (UmAS). Key to high enantioselection is the finding that ortho-iodo benzoic acid salts of the chiral copper(II) bis(oxazoline) catalyst deliver both diastereomers of the Henry adduct with high enantiomeric excess, homochiral at the oxygen-bearing carbon. Overall, this approach to α-oxy amides provides an innovative complement to alternatives that focus almost entirely on the enantioselective synthesis of α-oxy carboxylic acids.
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Affiliation(s)
- Matthew W. Leighty
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235
| | - Bo Shen
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235
| | - Jeffrey N. Johnston
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235
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Chhiba V, Bode ML, Mathiba K, Kwezi W, Brady D. Enantioselective biocatalytic hydrolysis of β-aminonitriles to β-amino-amides using Rhodococcus rhodochrous ATCC BAA-870. ACTA ACUST UNITED AC 2012. [DOI: 10.1016/j.molcatb.2011.12.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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15
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Lievano R, Pérez HI, Manjarrez N, Solís A, Solís-Oba M. Hydrolysis of ibuprofen nitrile and ibuprofen amide and deracemisation of ibuprofen using Nocardia corallina B-276. Molecules 2012; 17:3148-54. [PMID: 22410421 PMCID: PMC6268212 DOI: 10.3390/molecules17033148] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 03/06/2012] [Accepted: 03/07/2012] [Indexed: 11/24/2022] Open
Abstract
A novel application of whole cells of Nocardia corallina B-276 for the deracemisation of ibuprofen is reported. This microorganism successfully hydrolysed ibuprofen nitrile to ibuprofen amide, and ibuprofen amide to ibuprofen, using a suspension of cells in a potassium phosphate buffer solution (0.1 M, pH = 7.0). These results can be explained by the presence of NHase and amidase enzymes, but the reactions are not enantioselective and low ee values were obtained. However, (R)-ibuprofen was isolated with > 99% ee by a deracemisation process catalysed by N. corallina B-276. This is the first report of this kind of catalysis with this microorganism.
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Affiliation(s)
- Ricardo Lievano
- Departamento de Sistemas Biológicos, Universidad Autónoma Metropolitana Unidad Xochimilco, Calzada del Hueso No. 1100, Col. Villa Quietud, Delegación Coyoacán, C.P. 04960 México, D.F., Mexico
| | - Herminia Inés Pérez
- Departamento de Sistemas Biológicos, Universidad Autónoma Metropolitana Unidad Xochimilco, Calzada del Hueso No. 1100, Col. Villa Quietud, Delegación Coyoacán, C.P. 04960 México, D.F., Mexico
| | - Norberto Manjarrez
- Departamento de Sistemas Biológicos, Universidad Autónoma Metropolitana Unidad Xochimilco, Calzada del Hueso No. 1100, Col. Villa Quietud, Delegación Coyoacán, C.P. 04960 México, D.F., Mexico
| | - Aida Solís
- Departamento de Sistemas Biológicos, Universidad Autónoma Metropolitana Unidad Xochimilco, Calzada del Hueso No. 1100, Col. Villa Quietud, Delegación Coyoacán, C.P. 04960 México, D.F., Mexico
| | - Myrna Solís-Oba
- Centro de Investigación en Biotecnología Ambiental, Instituto Politécnico Nacional, Carretera Estatal Santa Inés Tecuexcomac-Tepetitla Km 1.5, C.P. 90700, Tlaxcala, Mexico
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Baum S, Williamson DS, Sewell T, Stolz A. Conversion of sterically demanding α,α-disubstituted phenylacetonitriles by the arylacetonitrilase from Pseudomonas fluorescens EBC191. Appl Environ Microbiol 2012; 78:48-57. [PMID: 22020513 PMCID: PMC3255610 DOI: 10.1128/aem.05570-11] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Accepted: 10/12/2011] [Indexed: 11/20/2022] Open
Abstract
The nitrilase from Pseudomonas fluorescens EBC191 converted 2-methyl-2-phenylpropionitrile, which contains a quaternary carbon atom in the α-position toward the nitrile group, and also similar sterically demanding substrates, such as 2-hydroxy-2-phenylpropionitrile (acetophenone cyanohydrin) or 2-acetyloxy-2-methylphenylacetonitrile. 2-Methyl-2-phenylpropionitrile was hydrolyzed to almost stoichiometric amounts of the corresponding acid. Acetophenone cyanohydrin was transformed to the corresponding acid (atrolactate) and amide (atrolactamide) at a ratio of about 3.4:1. The (R)-acid and the (S)-amide were formed preferentially from acetophenone cyanohydrin. A homology model of the nitrilase suggested that steric hindrance with amino acid residue Tyr54 could impair the binding or conversion of sterically demanding substrates. Therefore, several enzyme variants that carried mutations in the respective residues were generated and subsequently analyzed for the substrate specificity and enantioselectivity of the reactions. Enzyme variants that demonstrated increased relative activities for the conversion of acetophenone cyanohydrin were identified. The chiral analysis of these reactions demonstrated peculiar reaction kinetics, which suggested that the enzyme variants converted the nonpreferred (S)-enantiomer of acetophenone cyanohydrin with a higher reaction rate than that of the (preferred) (R)-enantiomer. Recombinant whole-cell catalysts that simultaneously produced the nitrilase from P. fluorescens EBC191 and a plant-derived (S)-oxynitrilase from cassava (Manihot esculenta) converted acetophenone plus cyanide at pH 4.5 to (S)-atrolactate and (S)-atrolactamide. These recombinant cells are promising catalysts for the synthesis of stable chiral quaternary carbon centers from ketones.
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Affiliation(s)
- Stefanie Baum
- Institut für Mikrobiologie, Universität Stuttgart, Stuttgart, Germany
| | - Dael S. Williamson
- Electron Microscope Unit, University of Cape Town, Rondebosch, South Africa
| | - Trevor Sewell
- Electron Microscope Unit, University of Cape Town, Rondebosch, South Africa
| | - Andreas Stolz
- Institut für Mikrobiologie, Universität Stuttgart, Stuttgart, Germany
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18
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Clouthier CM, Pelletier JN. Expanding the organic toolbox: a guide to integrating biocatalysis in synthesis. Chem Soc Rev 2012; 41:1585-605. [DOI: 10.1039/c2cs15286j] [Citation(s) in RCA: 251] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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