101
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Hanson R, Davis B, Chen Y, Goldberg S, Parker W, Tully T, Montana M, Patel R. Preparation of (R)-Amines from Racemic Amines with an (S)-Amine Transaminase fromBacillus megaterium. Adv Synth Catal 2008. [DOI: 10.1002/adsc.200800084] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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102
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Seo JH, Park HY, Kim J, Lee BS, Kim BG. Exploring sequence space: Profile analysis and protein-ligand docking to screen ω-aminotransferases with expanded substrate specificity. Biotechnol J 2008; 3:676-86. [DOI: 10.1002/biot.200700264] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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103
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Höhne M, Robins K, Bornscheuer U. A Protection Strategy Substantially Enhances Rate and Enantioselectivity in ω-Transaminase-Catalyzed Kinetic Resolutions. Adv Synth Catal 2008. [DOI: 10.1002/adsc.200800030] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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104
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Cho BK, Park HY, Seo JH, Kim J, Kang TJ, Lee BS, Kim BG. 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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Affiliation(s)
- Byung-Kwan Cho
- School of Chemical and Biological Engineering, Seoul National University, Seoul 151-742, Korea
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105
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Kaulmann U, Smithies K, Smith ME, Hailes HC, Ward JM. Substrate spectrum of ω-transaminase from Chromobacterium violaceum DSM30191 and its potential for biocatalysis. Enzyme Microb Technol 2007. [DOI: 10.1016/j.enzmictec.2007.05.011] [Citation(s) in RCA: 177] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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106
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Chen D, Wang Z, Zhang Y, Sun Z, Zhu Q. An amine: hydroxyacetone aminotransferase from Moraxella lacunata WZ34 for alaninol synthesis. Bioprocess Biosyst Eng 2007; 31:283-9. [PMID: 17849151 DOI: 10.1007/s00449-007-0158-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2007] [Accepted: 08/22/2007] [Indexed: 10/22/2022]
Abstract
An amine:hydroxyacetone aminotransferase from an isolated soil bacterium, Moraxella lacunata WZ34, was employed to synthesize alaninol in the presence of hydroxyacetone and isopropylamine in this study. The optimal carbon and nitrogen sources were glycerol and beef extract, respectively. A wide range of amino donor specificity was detected with the aminotransferase, which exhibited a relative high activity (9.83 U mL(-1)) in the presence of isopropylamine. The enzyme was the most active at pH 8.5, and showed relatively higher activity at alkaline than acidic pH. Maximum activity was achieved at 30 degrees C, and the enzyme had good thermal stability below 60 degrees C. Metal ions such as Mg(2+) had positive effect (132.6%) on the enzyme, and (aminooxy)acetic acid, a typical aminotransferase inhibitor, significantly inhibited its activity. The enzyme activity was enhanced by the addition of 0.05 mM pyridoxal-5'-phosphate (PLP).
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Affiliation(s)
- Dongzhi Chen
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou, 310032, China
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107
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Yi SS, Lee CW, Kim J, Kyung D, Kim BG, Lee YS. Covalent immobilization of ω-transaminase from Vibrio fluvialis JS17 on chitosan beads. Process Biochem 2007. [DOI: 10.1016/j.procbio.2007.01.008] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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108
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Kim J, Kyung D, Yun H, Cho BK, Seo JH, Cha M, Kim BG. 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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Affiliation(s)
- Juhan Kim
- School of Chemical Engineering, Seoul National University, Seoul 151-742, Korea
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109
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Ahn JH, Hwang MY, Lee KH, Choi CY, Kim DM. Use of signal sequences as an in situ removable sequence element to stimulate protein synthesis in cell-free extracts. Nucleic Acids Res 2006; 35:e21. [PMID: 17185295 PMCID: PMC1849898 DOI: 10.1093/nar/gkl917] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
This study developed a method to boost the expression of recombinant proteins in a cell-free protein synthesis system without leaving additional amino acid residues. It was found that the nucleotide sequences of the signal peptides serve as an efficient downstream box to stimulate protein synthesis when they were fused upstream of the target genes. The extent of stimulation was critically affected by the identity of the second codons of the signal sequences. Moreover, the yield of the synthesized protein was enhanced by as much as 10 times in the presence of an optimal second codon. The signal peptides were in situ cleaved and the target proteins were produced in their native sizes by carrying out the cell-free synthesis reactions in the presence of Triton X-100, most likely through the activation of signal peptidase in the S30 extract. The amplification of the template DNA and the addition of the signal sequences were accomplished by PCR. Hence, elevated levels of recombinant proteins were generated within several hours.
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Affiliation(s)
- Jin-Ho Ahn
- Interdisciplinary Program for Biochemical Engineering and Biotechnology, College of Engineering, Seoul National UniversitySeoul 151-742, Korea
| | - Mi-Yeon Hwang
- School of Chemical and Biological Engineering, College of Engineering, Seoul National UniversitySeoul 151-742, Korea
| | - Kyung-Ho Lee
- Department of Fine Chemical Engineering and Chemistry, Chungnam National UniversityDaejeon 305-764, Korea
| | - Cha-Yong Choi
- Interdisciplinary Program for Biochemical Engineering and Biotechnology, College of Engineering, Seoul National UniversitySeoul 151-742, Korea
- School of Chemical and Biological Engineering, College of Engineering, Seoul National UniversitySeoul 151-742, Korea
| | - Dong-Myung Kim
- Department of Fine Chemical Engineering and Chemistry, Chungnam National UniversityDaejeon 305-764, Korea
- To whom correspondence should be addressed. Tel: +82 42 821 5899; Fax: +82 42 823 7692;
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110
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Ingram CU, Bommer M, Smith MEB, Dalby PA, Ward JM, Hailes HC, Lye GJ. One-pot synthesis of amino-alcohols using a de-novo transketolase and β-alanine: Pyruvate transaminase pathway inEscherichia coli. Biotechnol Bioeng 2006; 96:559-69. [PMID: 16902948 DOI: 10.1002/bit.21125] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Biocatalysis continues to emerge as a powerful technique for the efficient synthesis of optically pure pharmaceuticals that are difficult to access via conventional chemistry. The power of biocatalysis can be enhanced if two or more reactions can be achieved by a single whole cell biocatalyst containing a pathway designed de-novo to facilitate a required synthetic sequence. The enzymes transketolase (TK) and transaminase (TAm) respectively catalyze asymmetric carbon--carbon bond formation and amine group addition to suitable substrate molecules. The ability of a transaminase to accept the product of the transketolase reaction can allow the two catalysts to be employed in series to create chiral amino-alcohols from achiral substrates. As proof of principle, the beta-alanine: pyruvate aminotransferase (beta-A:P TAm) from Pseudomonas aeruginosa has been cloned, to create plasmid pQR428, for overexpression in E.coli strain BL21gold(DE3). Production of the beta-A:P TAm alongside the native transketolase (overexpressed from plasmid pQR411), in a single E.coli host, has created a novel biocatalyst capable of the synthesis of chiral amino alcohols via a synthetic two-step pathway. The feasibility of using the biocatalyst has been demonstrated by the formation of a single diastereoisomer of 2-amino-1,3,4-butanetriol (ABT) product, in up to 21% mol/mol yield, by the beta-A:P TAm, via transamination of L-erythrulose synthesized by TK, from achiral substrates glycolaldehyde (GA) and beta-hydroxypyruvate (beta-HPA). ABT synthesis was achieved in a one-pot process, using either whole cells of the dual plasmid strain or cell lysate, while the dual alcohol-amine functionality of ABT makes it an excellent synthon for many pharmaceutical syntheses.
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Affiliation(s)
- C U Ingram
- Department of Biochemical Engineering, University College London, London, WC1E 7JW, United Kingdom
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111
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Yun H, Kim J, Kinnera K, Kim BG. Synthesis of enantiomerically puretrans-(1R,2R)- andcis-(1S,2R)-1-amino-2-indanol by lipase and ω-transaminase. Biotechnol Bioeng 2006; 93:391-5. [PMID: 16302257 DOI: 10.1002/bit.20721] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Syntheses of trans-(1R,2R) and cis-(1S,2R)-1-amino-2-indanol (AI) were accomplished by a series of enantioselective enzymatic reactions using lipase and transaminase (TA). Lipase catalysed enantioselective hydrolysis of 2-acetoxyindanone was employed to prepare (R)-2-hydroxy indanone (HI). trans-AI (5 mM) (de > 98%) was produced from 20 mM (R)-2- HI using omega-TA and 50 mM (S)-1-aminoindan as an amino donor in water-saturated ethyl acetate. For the production of cis-AI, the diastereomeric (2R)-AI was synthesized from (R)-2-HI using reductive amination, and the kinetic resolution was performed with omega-TA. The enantioselectivity of omega-TA for (2R)-AI was increased to 22.1 in the presence of 5% gamma-cyclodextrin. cis-AI (15.4 mM) (96% de) was obtained from 40 mM (2R)-AI using 30 mM pyruvate and omega-TA (25 mg) in 10 mL of 100 mM phosphate buffer (pH 7.0).
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Affiliation(s)
- Hyungdon Yun
- Laboratory of Biotechnology and Biomaterials, Institute of Molecular Biology and Genetics, School of Chemical and Biological Engineering, Seoul National University, Seoul, 151-742, Korea
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112
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Yun H, Hwang BY, Lee JH, Kim BG. Use of enrichment culture for directed evolution of the Vibrio fluvialis JS17 omega-transaminase, which is resistant to product inhibition by aliphatic ketones. Appl Environ Microbiol 2005; 71:4220-4. [PMID: 16085806 PMCID: PMC1183280 DOI: 10.1128/aem.71.8.4220-4224.2005] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A novel high-throughput screening method that overcame product inhibition was used to isolate a mutant omega-transaminase from Vibrio fluvialis JS17. An enzyme library was generated using error-prone PCR mutagenesis and then enriched on minimal medium containing 2-aminoheptane as the sole nitrogen source and 2-butanone as an inhibitory ketone. An identified mutant enzyme, omega-TAmla, showed significantly reduced product inhibition by aliphatic ketone. The product inhibition constants of the mutant with 2-butanone and 2-heptanone were 6- and 4.5-fold higher than those of the wild type, respectively. Using omega-TAmla (50 U/ml) overexpressed in Escherichia coli BL21, 150 mM 2-aminoheptane was successfully resolved to (R)-2-aminoheptane (enantiomeric excess, >99%) with 53% conversion with an enantioselectivity of >100.
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Affiliation(s)
- Hyungdon Yun
- School of Chemical Engineering and Institute of Molecular Biology and Genetics, Seoul National University, Seoul, South Korea
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113
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Yun H, Lim S, Cho BK, Kim BG. omega-Amino acid:pyruvate transaminase from Alcaligenes denitrificans Y2k-2: a new catalyst for kinetic resolution of beta-amino acids and amines. Appl Environ Microbiol 2004; 70:2529-34. [PMID: 15066855 PMCID: PMC383019 DOI: 10.1128/aem.70.4.2529-2534.2004] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Alcaligenes denitrificans Y2k-2 was obtained by selective enrichment followed by screening from soil samples, which showed omega-amino acid:pyruvate transaminase activity, to kinetically resolve aliphatic beta-amino acid, and the corresponding structural gene (aptA) was cloned. The gene was functionally expressed in Escherichia coli BL21 by using an isopropyl-beta-D-thiogalactopyranoside (IPTG)-inducible pET expression system (9.6 U/mg), and the recombinant AptA was purified to show a specific activity of 77.2 U/mg for L-beta-amino-n-butyric acid (L-beta-ABA). The enzyme converts various beta-amino acids and amines to the corresponding beta-keto acids and ketones by using pyruvate as an amine acceptor. The apparent K(m) and V(max) for L-beta-ABA were 56 mM and 500 U/mg, respectively, in the presence of 10 mM pyruvate. In the presence of 10 mM L-beta-ABA, the apparent K(m) and V(max) for pyruvate were 11 mM and 370 U/mg, respectively. The enzyme exhibits high stereoselectivity (E > 80) in the kinetic resolution of 50 mM D,L-beta-ABA, producing optically pure D-beta-ABA (99% enantiomeric excess) with 53% conversion.
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Affiliation(s)
- Hyungdon Yun
- Institute for Molecular Biology and Genetics and School of Chemical Engineering, Seoul National University, Seoul 151-742, Korea
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114
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Yun H, Cho BK, Kim BG. Kinetic resolution of (R,S)-sec-butylamine using omega-transaminase fromVibrio fluvialis JS17 under reduced pressure. Biotechnol Bioeng 2004; 87:772-8. [PMID: 15329935 DOI: 10.1002/bit.20186] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The kinetic resolution of (R,S) sec-butylamine with the omega-transaminase (TA) from Vibrio fluvialis JS17 was performed under reduced pressure (e.g., 150 torr) to selectively remove an inhibitory product (2-butanone). The evaporation kinetics of 2-butanone at 150 torr in the buffer solution followed the first-order rate law, and the evaporation rate constant was 2.19 1/h, and independent of pH, while the evaporation kinetics of sec-butylamine is dependent on pH. A simple mathematical model of the evaporation of sec-butylamine allowing the estimation of its concentration in the reaction media was developed. The evaporation rate constant of its free amine form and the protonated amine form were 1.00 1/h, and nearly zero, respectively. Although the optimum pH of the omega-TA activity for sec-butylamine is 9.0, the optimal pH of the enzyme reaction under reduced pressure was pH 7.0, due to the higher evaporation rate of sec-butylamine at higher pH above 7.0. Using the recombinant Escherichia coli BL21 overexpressing omega-TA, 400 mM racemic sec-butylamine was resolved successfully to 98% ee of (R)-sec-butylamine with 53% conversion at 150 torr and pH 7.0.
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Affiliation(s)
- Hyungdon Yun
- Laboratory of Molecular Biotechnology and Biomaterials, Institute for Molecular Biology and Genetics, Seoul National University, 151-742, Korea
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