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Efficient Production of L‐Homophenylalanine by Enzymatic‐Chemical Cascade Catalysis. Angew Chem Int Ed Engl 2022; 61:e202207077. [DOI: 10.1002/anie.202207077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Indexed: 11/06/2022]
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2
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Efficient Production of L‐homophenylalanine by Enzymatic–Chemical Cascade Catalysis. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202207077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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3
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A Techno-economic Assessment of a Biocatalytic Chiral Amine Production Process Integrated with In Situ Membrane Extraction. Org Process Res Dev 2022. [DOI: 10.1021/acs.oprd.1c00464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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4
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Reprogramming natural proteins using unnatural amino acids. RSC Adv 2021; 11:38126-38145. [PMID: 35498070 PMCID: PMC9044140 DOI: 10.1039/d1ra07028b] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Accepted: 11/18/2021] [Indexed: 12/26/2022] Open
Abstract
Unnatural amino acids have gained significant attention in protein engineering and drug discovery as they allow the evolution of proteins with enhanced stability and activity. The incorporation of unnatural amino acids into proteins offers a rational approach to engineer enzymes for designing efficient biocatalysts that exhibit versatile physicochemical properties and biological functions. This review highlights the biological and synthetic routes of unnatural amino acids to yield a modified protein with altered functionality and their incorporation methods. Unnatural amino acids offer a wide array of applications such as antibody-drug conjugates, probes for change in protein conformation and structure–activity relationships, peptide-based imaging, antimicrobial activities, etc. Besides their emerging applications in fundamental and applied science, systemic research is necessary to explore unnatural amino acids with novel side chains that can address the limitations of natural amino acids. Incorporation of unnatural amino acids into protein offers wide array of applications in fundamental and applied science.![]()
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Abstract
Reactive crystallization is not new, but there has been recent growth in its use as a means of improving performance and sustainability of industrial processes.
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Structure-guided engineering of Pseudomonas dacunhael-aspartate β-decarboxylase for l-homophenylalanine synthesis. Chem Commun (Camb) 2020; 56:13876-13879. [PMID: 33094304 DOI: 10.1039/d0cc05871h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Structure-guided engineering of Pseudomonas dacunhael-aspartate β-decarboxylase (AspBDC) resulted in a double mutant (R37A/T382G) with remarkable 15 400-fold improvement in specific activity reaching 216 mU mg-1, towards the target substrate 3(R)-benzyl-l-aspartate. A novel strategy for enzymatic synthesis of l-homophenylalanine was developed by using the variant as a biocatalyst affording 75% product yield within 12 h. Our results underscore the potential of engineered AspBDC for the biocatalytic synthesis of pharmaceutically relevant and value added unnatural l-amino acids.
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7
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Artificial Biocatalytic Cascade with Three Enzymes in One Pot for Asymmetric Synthesis of Chiral Unnatural Amino Acids. European J Org Chem 2019. [DOI: 10.1002/ejoc.201900828] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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8
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Advances in 2-phenylethanol production from engineered microorganisms. Biotechnol Adv 2019; 37:403-409. [DOI: 10.1016/j.biotechadv.2019.02.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 01/25/2019] [Accepted: 02/11/2019] [Indexed: 12/11/2022]
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9
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Unnatural amino acids: production and biotechnological potential. World J Microbiol Biotechnol 2019; 35:67. [DOI: 10.1007/s11274-019-2642-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 03/28/2019] [Indexed: 01/01/2023]
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10
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Application of In Situ Product Crystallization and Related Techniques in Biocatalytic Processes. Chemistry 2019; 25:4871-4884. [DOI: 10.1002/chem.201804970] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 11/04/2018] [Indexed: 01/25/2023]
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11
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Thermostable Branched-Chain Amino Acid Transaminases From the Archaea Geoglobus acetivorans and Archaeoglobus fulgidus: Biochemical and Structural Characterization. Front Bioeng Biotechnol 2019; 7:7. [PMID: 30733943 PMCID: PMC6353796 DOI: 10.3389/fbioe.2019.00007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 01/08/2019] [Indexed: 11/25/2022] Open
Abstract
Two new thermophilic branched chain amino acid transaminases have been identified within the genomes of different hyper-thermophilic archaea, Geoglobus acetivorans, and Archaeoglobus fulgidus. These enzymes belong to the class IV of transaminases as defined by their structural fold. The enzymes have been cloned and over-expressed in Escherichia coli and the recombinant enzymes have been characterized both biochemically and structurally. Both enzymes showed high thermostability with optimal temperature for activity at 80 and 85°C, respectively. They retain good activity after exposure to 50% of the organic solvents, ethanol, methanol, DMSO and acetonitrile. The enzymes show a low activity to (R)-methylbenzylamine but no activity to (S)-methylbenzylamine. Both enzymes have been crystallized and their structures solved in the internal aldimine form, to 1.9 Å resolution for the Geoglobus enzyme and 2.0 Å for the Archaeoglobus enzyme. Also the Geoglobus enzyme structure has been determined in complex with the amino acceptor α-ketoglutarate and the Archaeoglobus enzyme in complex with the inhibitor gabaculine. These two complexes have helped to determine the conformation of the enzymes during enzymatic turnover and have increased understanding of their substrate specificity. A comparison has been made with another (R) selective class IV transaminase from the fungus Nectria haematococca which was previously studied in complex with gabaculine. The subtle structural differences between these enzymes has provided insight regarding their different substrate specificities.
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13
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Driving Transamination Irreversible by Decomposing Byproduct α-Ketoglutarate into Ethylene Using Ethylene-Forming Enzyme. Catal Letters 2018. [DOI: 10.1007/s10562-018-2552-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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14
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Development of an in situ-Product Crystallization (ISPC)-Concept to Shift the Reaction Equilibria of Selected Amine Transaminase-Catalyzed Reactions. European J Org Chem 2018. [DOI: 10.1002/ejoc.201800323] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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15
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Abstract
This review summarizes the progress achieved in the enzymatic asymmetric synthesis of chiral amino acids from prochiral substrates.
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Cosynthesis of l-homophenylalanine and 2-phenylethanol by recombinant Saccharomyces cerevisiae expressing aspartate aminotransferase from Escherichia coli BL21(DE3). J Biosci Bioeng 2017; 123:1-7. [DOI: 10.1016/j.jbiosc.2016.06.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 06/21/2016] [Accepted: 06/22/2016] [Indexed: 11/25/2022]
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18
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19
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Kinetics of reactive extraction of equol enantiomers from organic phase by hydroxypropyl-β-cyclodextrin. Sep Purif Technol 2016. [DOI: 10.1016/j.seppur.2016.06.054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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20
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Synthesis of enantiopure l-(5-phenylfuran-2-yl)alanines by a sequential multienzyme process. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.tetasy.2015.08.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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21
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Effect of PEGylation on the activity and stability of horseradish peroxidase and l-N-carbamoylase in aqueous phases. Process Biochem 2015. [DOI: 10.1016/j.procbio.2015.04.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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22
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Microparticle-Based Strategy for Controlled Release of Substrate for the Biocatalytic Preparation of l-Homophenylalanine. ACS Catal 2014. [DOI: 10.1021/cs4011919] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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23
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The substrate specificity, enantioselectivity and structure of the (R)-selective amine : pyruvate transaminase from Nectria haematococca. FEBS J 2014; 281:2240-53. [PMID: 24618038 PMCID: PMC4255305 DOI: 10.1111/febs.12778] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 03/03/2014] [Accepted: 03/05/2014] [Indexed: 11/30/2022]
Abstract
During the last decade the use of transaminases for the production of pharmaceutical and fine chemical intermediates has attracted a great deal of attention. Transaminases are versatile biocatalysts for the efficient production of amine intermediates and many have (S)-enantiospecificity. Transaminases with (R)-specificity are needed to expand the applications of these enzymes in biocatalysis. In this work we have identified a fungal putative (R)-specific transaminase from the Eurotiomycetes Nectria haematococca, cloned a synthetic version of this gene, demonstrated (R)-selective deamination of several substrates including (R)-α-methylbenzylamine, as well as production of (R)-amines, and determined its crystal structure. The crystal structures of the holoenzyme and the complex with an inhibitor gabaculine offer the first detailed insight into the structural basis for substrate specificity and enantioselectivity of the industrially important class of (R)-selective amine : pyruvate transaminases.
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Enhancement of biocatalytic efficiency by increasing substrate loading: enzymatic preparation of L-homophenylalanine. Appl Microbiol Biotechnol 2013; 97:8487-94. [PMID: 23893309 DOI: 10.1007/s00253-013-5117-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 05/27/2013] [Accepted: 07/10/2013] [Indexed: 10/26/2022]
Abstract
Enantiomerically pure L-homophenylalanine (L-HPA) is a key building block for the synthesis of angiotensin-converting enzyme inhibitors and other chiral pharmaceuticals. Among the processes developed for the L-HPA production, biocatalytic synthesis employing phenylalanine dehydrogenase has been proven as the most promising route. However, similar to other dehydrogenase-catalyzed reactions, the viability of this process is markedly affected by insufficient substrate loading and high costs of the indispensable cofactors. In the present work, a highly efficient and economic biocatalytic process for L-HPA was established by coupling genetically modified phenylalanine dehydrogenase and formate dehydrogenase. Combination of fed-batch substrate addition and a continuous product removal greatly increased substrate loading and cofactor utilization. After systemic optimization, 40 g (0.22 mol) of keto acid substrate was transformed to L-HPA within 24 h and a total of 0.2 mM NAD(+) was reused effectively in eight cycles of fed-batch operation, consequently giving an average substrate concentration of 510 mM and a productivity of 84.1 g l(-1) day(-1) for L-HPA. The present study provides an efficient and feasible enzymatic process for the production of L-HPA and a general solution for the increase of substrate loading.
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25
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A 1-step microplate method for assessing the substrate range of l-α-amino acid aminotransferase. Enzyme Microb Technol 2013; 52:218-25. [DOI: 10.1016/j.enzmictec.2013.02.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2012] [Revised: 02/13/2013] [Accepted: 02/14/2013] [Indexed: 11/20/2022]
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26
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Immobilization of phenylalanine dehydrogenase onto Eupergit CM for the synthesis of (S)-2-amino-4-phenylbutyric acid. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/j.molcatb.2012.11.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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27
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Protein-based biorefining: metabolic engineering for production of chemicals and fuel with regeneration of nitrogen fertilizers. Appl Microbiol Biotechnol 2013; 97:1397-406. [DOI: 10.1007/s00253-012-4605-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 11/17/2012] [Accepted: 11/20/2012] [Indexed: 11/24/2022]
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28
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29
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Determination of Kinetics in Biphasic Recognition Chiral Extraction for Separation of Phenylsuccinic Acid Enantiomers. SEP SCI TECHNOL 2011. [DOI: 10.1080/01496395.2011.590173] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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30
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Removal of l-alanine from the production of l-2-aminobutyric acid by introduction of alanine racemase and d-amino acid oxidase. Appl Microbiol Biotechnol 2011; 90:903-10. [DOI: 10.1007/s00253-011-3127-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Revised: 01/10/2011] [Accepted: 01/10/2011] [Indexed: 10/18/2022]
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31
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Synthesis of l-homophenylalanine via integrated membrane bioreactor: Influence of pH on yield. Biochem Eng J 2010. [DOI: 10.1016/j.bej.2010.08.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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32
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Asymmetric synthesis of l-tert-leucine and l-3-hydroxyadamantylglycine using branched chain aminotransferase. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/j.molcatb.2010.05.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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33
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34
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Flow chemistry kinetic studies reveal reaction conditions for ready access to unsymmetrical trehalose analogues. Org Biomol Chem 2010; 8:4232-5. [DOI: 10.1039/c0ob00226g] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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35
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Biocatalytic asymmetric amination of carbonyl functional groups - a synthetic biology approach to organic chemistry. Biotechnol J 2009; 4:1420-31. [DOI: 10.1002/biot.200900110] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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36
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Asymmetrically simultaneous synthesis of L-homophenylalanine and N6-protected-2-oxo-6-amino-hexanoic acid by engineered Escherichia coli aspartate aminotransferase. Biotechnol Prog 2009; 25:1637-42. [PMID: 19768786 DOI: 10.1002/btpr.272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
L-Homophenylalanine (L-HPA) and N(6)-protected-2-oxo-6-amino-hexanoic acid (N(6)-protected-OAHA) can be used as building blocks for the manufacture of angiotensin-converting enzyme inhibitors. To synthesize L-HPA and N(6)-protected-OAHA simultaneously from 2-oxo-4-phenylbutanoic acid (OPBA) and N(6)-protected-L-lysine, several variants of Escherichia coli aspartate aminotransferase (AAT) were developed by site-directed mutagenesis and their catalytic activities were investigated. Three kinds of N(6)-protected-L-lysine were tested as potential amino donors for the bioconversion process. AAT variants of R292E/L18H and R292E/L18T exhibited specific activities of 0.70+/-0.01 U/mg protein and 0.67+/-0.02 U/mg protein to 2-amino-6-tert-butoxycarbonylamino-hexanoic acid (BOC-lysine) and 2-amino-6-(2,2,2-trifluoro-acetylamino)-hexanoic acid, respectively. E. coli cells expressing R292E/L18H variant were able to convert OPBA and BOC-lysine to L-HPA and 2-oxo-6-tert-butoxycarbonylamino-hexanoic acid (BOC-OAHA) with 96.2% yield in 8 h. This is the first report demonstrating a process for the simultaneous production of two useful building blocks, L-HPA and BOC-OAHA.
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37
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Sustainable biocatalytic synthesis of L-homophenylalanine as pharmaceutical drug precursor. Biotechnol Adv 2009; 27:286-96. [DOI: 10.1016/j.biotechadv.2009.01.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Revised: 01/02/2009] [Accepted: 01/14/2009] [Indexed: 11/17/2022]
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38
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Simultaneous synthesis of 2-phenylethanol and L-homophenylalanine using aromatic transaminase with yeast Ehrlich pathway. Biotechnol Bioeng 2009; 102:1323-9. [DOI: 10.1002/bit.22178] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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39
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Asymmetrical Synthesis of l-Homophenylalanine Using Engineered Escherichia coli Aspartate Aminotransferase. Biotechnol Prog 2008; 21:411-5. [PMID: 15801779 DOI: 10.1021/bp049756i] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Site-directed mutagenesis was performed to change the substrate specificity of Escherichia coli aspartate aminotransferase (AAT). A double mutant, R292E/L18H, with a 12.9-fold increase in the specific activity toward L-lysine and 2-oxo-4-phenylbutanoic acid (OPBA) was identified. E. coli cells expressing this mutant enzyme could convert OPBA to L-homophenylalanine (L-HPA) with 97% yield and more than 99.9% ee using L-lysine as amino donor. The transamination product of L-lysine, 2-keto-6-aminocaproate, was cyclized nonenzymatically to form Delta(1)-piperideine 2-carboxylic acid in the reaction mixture. The low solubility of L-HPA and spontaneous cyclization of 2-keto-6-aminocaproate drove the reaction completely toward L-HPA production. This is the first aminotransferase process using L-lysine as inexpensive amino donor for the L-HPA production to be reported.
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40
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Redesigning the substrate specificity of omega-aminotransferase for the kinetic resolution of aliphatic chiral amines. Biotechnol Bioeng 2008; 99:275-84. [PMID: 17680656 DOI: 10.1002/bit.21591] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Substrate specificity of the omega-aminotransferase obtained from Vibrio fluvialis (omega-ATVf) was rationally redesigned for the kinetic resolution of aliphatic chiral amines. omega-ATVf showed unique substrate specificity toward aromatic amines with a high enantioselectivity (E > 100) for (S)-enantiomers. However, the substrate specificity of this enzyme was much narrower toward aliphatic amines. To overcome the narrow substrate specificity toward aliphatic amines, we redesigned the substrate specificity of omega-ATVf using homology modeling and the substrate structure- activity relationship. The homology model and the substrate structure-activity relationship showed that the active site of omega-ATVf consists of one large substrate-binding site and another small substrate-binding site. The key determinant in the small substrate-binding site was D25, whose role was expected to mask R415 and to generate the electrostatic repulsion with the substrate's alpha-carboxylate group. In the large substrate-binding site, R256 was predicted to recognize the alpha-carboxylate group of substrate thus obeying the dual substrate recognition mechanism of aminotransferase subgroup II enzymes. Among the several amino acid residues in the large substrate-binding site, W57 and W147, with their bulky side chains, were expected to restrict the recognition of aliphatic amines. Two mutant enzymes, W57G and W147G, showed significant changes in their substrate specificity such that they catalyzed transamination of a broad range of aliphatic amines without losing the original activities toward aromatic amines and enantioselectivity.
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41
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Stereoselective synthesis of l-homophenylalanine using the carbamoylase method with in situ racemization via N-acylamino acid racemase. Process Biochem 2007. [DOI: 10.1016/j.procbio.2007.02.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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42
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Cloning and characterization of a novel beta-transaminase from Mesorhizobium sp. strain LUK: a new biocatalyst for the synthesis of enantiomerically pure beta-amino acids. Appl Environ Microbiol 2007; 73:1772-82. [PMID: 17259358 PMCID: PMC1828820 DOI: 10.1128/aem.02119-06] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2006] [Accepted: 01/20/2007] [Indexed: 11/20/2022] Open
Abstract
A novel beta-transaminase gene was cloned from Mesorhizobium sp. strain LUK. By using N-terminal sequence and an internal protein sequence, a digoxigenin-labeled probe was made for nonradioactive hybridization, and a 2.5-kb gene fragment was obtained by colony hybridization of a cosmid library. Through Southern blotting and sequence analysis of the selected cosmid clone, the structural gene of the enzyme (1,335 bp) was identified, which encodes a protein of 47,244 Da with a theoretical pI of 6.2. The deduced amino acid sequence of the beta-transaminase showed the highest sequence similarity with glutamate-1-semialdehyde aminomutase of transaminase subgroup II. The beta-transaminase showed higher activities toward d-beta-aminocarboxylic acids such as 3-aminobutyric acid, 3-amino-5-methylhexanoic acid, and 3-amino-3-phenylpropionic acid. The beta-transaminase has an unusually broad specificity for amino acceptors such as pyruvate and alpha-ketoglutarate/oxaloacetate. The enantioselectivity of the enzyme suggested that the recognition mode of beta-aminocarboxylic acids in the active site is reversed relative to that of alpha-amino acids. After comparison of its primary structure with transaminase subgroup II enzymes, it was proposed that R43 interacts with the carboxylate group of the beta-aminocarboxylic acids and the carboxylate group on the side chain of dicarboxylic alpha-keto acids such as alpha-ketoglutarate and oxaloacetate. R404 is another conserved residue, which interacts with the alpha-carboxylate group of the alpha-amino acids and alpha-keto acids. The beta-transaminase was used for the asymmetric synthesis of enantiomerically pure beta-aminocarboxylic acids. (3S)-Amino-3-phenylpropionic acid was produced from the ketocarboxylic acid ester substrate by coupled reaction with a lipase using 3-aminobutyric acid as amino donor.
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43
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Synthesis of enantiopure (S)-2-hydroxyphenylbutanoic acid using novel hydroxy acid dehydrogenase from Enterobacter sp. BK2K. Biotechnol Prog 2007; 23:606-12. [PMID: 17302428 DOI: 10.1021/bp0602404] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Enterobacter sp. BK2K, screened from soil samples, can enantioselectively reduce 2-oxo-4-phenylbutanoic acid into (S)-2-hydroxy-4-phenylbutanoic acid. alpha-Hydroxy acid dehydrogenase (HADH) (specific activity 62.6 U/mg) was purified from the crude extract of Enterobacter sp. BK2K, and its gene was cloned and functionally expressed in E. coli BL21. The optimal pH and temperature for the HADH activity were 6.5 and 30 degrees C, respectively. The purified enzyme catalyzes the reduction of various aromatic and aliphatic 2-oxo carboxylic acids to the corresponding (S)-2-hydoxy carboxylic acids using NADH as cofactor. For example, the Km and kcat/Km for 2-oxo-4-phenylbutaonoic acid in the presence of 2 mM NADH were 6.8 mM and 350 M-1 min-1, respectively. For practical applications, a NADH recycle system employing the recombinant formate dehydrogenase from E. coli K12 was coupled with HADH in E. coli BL21. Using the recombinant HADH (110 U of 11 U/mg crude cell extract) and formate dehydrogenase (670 U of 67 U/mg crude cell extract) in 10 mL of 500 mM phosphate buffer (pH 6.5), 96 mM of (S)-phenyllactic acid (> 94% ee) and 95 mM of (S)-2-hydroxy-4-phenylbutanoic acid (> 94% ee) were produced in quantitative yields from 100 mM of phenylpyruvate and 2-oxo-4-phenylbutanoic acid.
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Asymmetric synthesis of nonproteinogenic amino acids with l-amino acid transaminase: synthesis of (2S)-2-amino-4-oxo-4-phenylbutyric and (3E,2S)-2-amino-4-phenylbutenoic acids. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/j.tetasy.2006.07.034] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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45
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Asymmetric synthesis of unnaturall-amino acids using thermophilic aromaticl-amino acid transaminase. BIOTECHNOL BIOPROC E 2006. [DOI: 10.1007/bf03026244] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Enantioselective Synthesis of l-Homophenylalanine by Whole Cells of RecombinantEscherichia coliExpressing l-Aminoacylase andN-Acylamino Acid Racemase Genes fromDeinococcus radioduransBCRC12827. Biotechnol Prog 2006. [DOI: 10.1002/bp0601241] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Engineering aromaticL-amino acid transaminase for the asymmetric synthesis of constrained analogs ofL-phenylalanine. Biotechnol Bioeng 2006; 94:842-50. [PMID: 16673402 DOI: 10.1002/bit.20902] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
An enzymatic asymmetric synthesis was carried out for the preparation of enantiomerically pure L-diphenylalanine using the rationally engineered aromatic L-amino acid transaminase (eAroATEs) obtained from Enterobacter sp. BK2K-1. To rationally redesign the enzyme, structural model was constructed by the homology modeling. The structural model was experimentally validated by the site-directed mutagenesis of the predicted pyridoxal-5'-phosphate (PLP) binding site and the substrate-recognition region, and the cell-free protein synthesis of mutated enzymes. It was suggested that Arg281 and Arg375 were the key residues to recognize the distal carboxylate and alpha-carboxylate group of the substrates, respectively. The model also predicted that Tyr66 forms hydrogen bond with the phosphate moiety of PLP and interacts with the side chain attached to beta-carbon of the amino acid substrate. Among the various site-directed mutants, Y66L variant was able to synthesize L-diphenylalanine with 23% conversion yield for 10 h, whereas the wild-type AroATEs was inactive for the transamination between diphenylpyruvate and L-phenylalanine as amino acceptor and amino donor, respectively.
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Enzymatic resolution for the preparation of enantiomerically enrichedD-?-heterocyclic alanine derivatives usingEscherichia coli aromaticL-amino acid transaminase. Biotechnol Bioeng 2004; 88:512-9. [PMID: 15459908 DOI: 10.1002/bit.20280] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
An enzymatic resolution was carried out for the preparation of enriched beta-heterocyclic D-alanine derivatives using Escherichia coli aromatic L-amino acid transaminase. The excess of pyrazole, imidazole, or 1,2,4-triazole reacted with methyl-2-acetamidoacrylate in acetonitrile in the presence of potassium carbonate at 60 degrees C, directly leading to make the potassium salt of the corresponding N-acetyl-beta-heterocyclic alanine derivatives. After the acidic deprotection of the N-acetyl group, 10 mM of racemic pyrazolylalanine, triazolylalanine, and imidazolylalanine were resolved to D-pyrazolylalanine, D-triazolylalanine, and D-imidazolylalanine with 46% (85% ee), 42% (72% ee), and 48% (95% ee) conversion yield in 18 h, respectively, using E. coli aromatic L-amino acid transaminase (EC 2.6.1.5). Although the three beta-heterocyclic L-alanine derivatives have similar molecular structures, they showed different reaction rates and enantioselectivities. The relative reactivities of the transaminase toward the beta-heterocyclic L-alanine derivatives could be explained by the relationship between the substrate binding energy (E, kcal/mol) to the enzyme active site and the distance (delta, A) from the nitrogen of alpha-amino group of the substrates to the C4' carbon of PLP-Lys258 Schiff base. As the ratio of the substrate binding energy (E) to the distance (delta) becomes indicative value of k(cat)/K(M) of the enzyme to the substrate, the relative reactivities of the beta-heterocyclic L-alanine derivatives were successfully correlated with E/delta, and the relationship was confirmed by our experiments.
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Simultaneous synthesis of enantiomerically pure (S)-amino acids and (R)-amines using α/ω-aminotransferase coupling reactions with two-liquid phase reaction system. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/j.molcatb.2003.07.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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