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De Capitani J, Mutschler H. The Long Road to a Synthetic Self-Replicating Central Dogma. Biochemistry 2023; 62:1221-1232. [PMID: 36944355 PMCID: PMC10077596 DOI: 10.1021/acs.biochem.3c00023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
The construction of a biochemical system capable of self-replication is a key objective in bottom-up synthetic biology. Throughout the past two decades, a rapid progression in the design of in vitro cell-free systems has provided valuable insight into the requirements for the development of a minimal system capable of self-replication. The main limitations of current systems can be attributed to their macromolecular composition and how the individual macromolecules use the small molecules necessary to drive RNA and protein synthesis. In this Perspective, we discuss the recent steps that have been taken to generate a minimal cell-free system capable of regenerating its own macromolecular components and maintaining the homeostatic balance between macromolecular biogenesis and consumption of primary building blocks. By following the flow of biological information through the central dogma, we compare the current versions of these systems to date and propose potential alterations aimed at designing a model system for self-replicative synthetic cells.
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Affiliation(s)
- Jacopo De Capitani
- Department of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Strasse 4a, 44227 Dortmund, Germany
| | - Hannes Mutschler
- Department of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Strasse 4a, 44227 Dortmund, Germany
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2
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Bailoni E, Poolman B. ATP Recycling Fuels Sustainable Glycerol 3-Phosphate Formation in Synthetic Cells Fed by Dynamic Dialysis. ACS Synth Biol 2022; 11:2348-2360. [PMID: 35377147 PMCID: PMC9295154 DOI: 10.1021/acssynbio.2c00075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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The bottom-up construction
of an autonomously growing, self-reproducing
cell represents a great challenge for synthetic biology. Synthetic
cellular systems are envisioned as out-of-equilibrium enzymatic networks
encompassed by a selectively open phospholipid bilayer allowing for
protein-mediated communication; internal metabolite recycling is another
key aspect of a sustainable metabolism. Importantly, gaining tight
control over the external medium is essential to avoid thermodynamic
equilibrium due to nutrient depletion or waste buildup in a closed
compartment (e.g., a test tube). Implementing a sustainable
strategy for phospholipid biosynthesis is key to expanding the cellular
boundaries. However, phospholipid biosynthesis is currently limited
by substrate availability, e.g., of glycerol 3-phosphate,
the essential core of phospholipid headgroups. Here, we reconstitute
an enzymatic network for sustainable glycerol 3-phosphate synthesis
inside large unilamellar vesicles. We exploit the Escherichia
coli glycerol kinase GlpK to synthesize glycerol 3-phosphate
from externally supplied glycerol. We fuel phospholipid headgroup
formation by sustainable l-arginine breakdown. In addition,
we design and characterize a dynamic dialysis setup optimized for
synthetic cells, which is used to control the external medium composition
and to achieve sustainable glycerol 3-phosphate synthesis.
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Affiliation(s)
- Eleonora Bailoni
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute & Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Bert Poolman
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute & Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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3
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Li J, Zhang C, Huang P, Kuru E, Forster-Benson ETC, Li T, Church GM. Dissecting limiting factors of the Protein synthesis Using Recombinant Elements (PURE) system. TRANSLATION (AUSTIN, TEX.) 2017; 5:e1327006. [PMID: 28702280 PMCID: PMC5501384 DOI: 10.1080/21690731.2017.1327006] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Revised: 04/14/2017] [Accepted: 04/28/2017] [Indexed: 01/10/2023]
Abstract
Reconstituted cell-free protein synthesis systems such as the Protein synthesis Using Recombinant Elements (PURE) system give high-throughput and controlled access to in vitro protein synthesis. Here we show that compared with the commercial S30 crude extract based RTS 100 E. coli HY system, the PURE system has less mRNA degradation and produces up to ∼6-fold full-length proteins. However the majority of polypeptides PURE produces are partially translated or inactive since the signal from firefly luciferase (Fluc) translated in PURE is only ∼2/3rd of that measured using the RTS 100 E. coli HY S30 system. Both of the 2 batch systems suffer from low ribosome recycling efficiency when translating proteins from 82 kD to 224 kD. A systematic fed-batch analysis of PURE shows replenishment of 6 small molecule substrates individually or in combination before energy depletion increased Fluc protein yield by ∼1.5 to ∼2-fold, while creatine phosphate and magnesium have synergistic effects when added to the PURE system. Additionally, while adding EF-P to PURE reduced full-length protein translated, it increased the fraction of functional protein and reduced partially translated protein probably by slowing down the translation process. Finally, ArfA, rather than YaeJ or PrfH, helped reduce ribosome stalling when translating Fluc and improved system productivity in a template-dependent fashion.
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Affiliation(s)
- Jun Li
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Wyss Harvard Institute of Biologically Inspired Engineering, Boston, MA, USA
| | - Chi Zhang
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Poyi Huang
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Erkin Kuru
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | | | - Taibo Li
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - George M. Church
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Wyss Harvard Institute of Biologically Inspired Engineering, Boston, MA, USA
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4
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Jackson K, Kanamori T, Ueda T, Fan ZH. Protein synthesis yield increased 72 times in the cell-free PURE system. Integr Biol (Camb) 2015; 6:781-8. [PMID: 25008400 DOI: 10.1039/c4ib00088a] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Compared to cell-based protein expression, cell-free protein synthesis (CFPS) offers several advantages including a greater control over system additives. This control is further enhanced with a CFPS system called the Protein synthesis Using Recombinant Elements (PURE) system, which consists of 108 purified transcriptional and translational elements. With the PURE system, all elements are known, nuclease and protease activities are reduced, and the concentration of each element can be optimized for maximal protein expression. However, protein expression yield with this system is relatively low due to the consumption of nutrients and energy molecules as well as the accumulation of inhibitory byproducts in the batch format. To enhance protein expression with the PURE system, we developed a feeding solution that was optimized using a miniaturized fluid array device (μFAD) in a continuous-exchange cell-free (CECF) format. The device enabled (1) continuous supply of energy/nutrient molecules from the feeding solution to the reaction solution where protein synthesis occurred, and (2) simultaneous removal of inhibitory expression byproducts from the reaction solution to the feeding solution. Consequently, the synthesis yield of green fluorescent protein (GFP) increased 72.5-fold in comparison with the same reaction in the conventional batch format.
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Affiliation(s)
- Kirsten Jackson
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, P.O. Box 116131, Gainesville, FL 32611, USA
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5
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Lian Q, Cao H, Wang F. The Cost-Efficiency Realization in the Escherichia coli-Based Cell-Free Protein Synthesis Systems. Appl Biochem Biotechnol 2014; 174:2351-67. [DOI: 10.1007/s12010-014-1143-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 08/06/2014] [Indexed: 01/08/2023]
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6
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Liguori L, Marques B, Villegas-Méndez A, Rothe R, Lenormand JL. Production of membrane proteins using cell–free expression systems. Expert Rev Proteomics 2014; 4:79-90. [PMID: 17288517 DOI: 10.1586/14789450.4.1.79] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Different overexpression systems are widely used in the laboratory to produce proteins in a reasonable amount for functional and structural studies. However, to optimize these systems without modifying the cellular functions of the living organism remains a challenging task. Cell-free expression systems have become a convenient method for the high-throughput expression of recombinant proteins, and great effort has been focused on generating high yields of proteins. Furthermore, these systems represent an attractive alternative for producing difficult-to-express proteins, such as membrane proteins. In this review, we highlight the recent improvements of these cell-free expression systems and their direct applications in the fields of membrane proteins production, protein therapy and modern proteomics.
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Affiliation(s)
- Lavinia Liguori
- University Joseph Fourier, HumProTher Laboratory, GREPI, CHU-Grenoble, 38043 Grenoble, France.
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7
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Rupp S. New bioproduction systems: from molecular circuits to novel reactor concepts in cell-free biotechnology. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2013; 137:103-23. [PMID: 23873094 DOI: 10.1007/10_2013_227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
: The last decades witnessed a strong growth in several areas of biotechnology, especially in fields related to health, as well as in industrial biotechnology. Advances in molecular engineering now enable biotechnologists to design more efficient pathways in order to convert a larger spectrum of renewable resources into industrially used biofuels and chemicals as well as into new pharmaceuticals and therapeutic proteins. In addition material sciences advanced significantly making it more and more possible to integrate biology and engineering. One of the key questions currently is how to develop new ways of engineering biological systems to cope with the complexity and limitations given by the cell. The options to integrate biology with classical engineering advanced cell free technologies in the recent years significantly. Cell free protein production using cellular extracts is now a well-established universal technology for production of proteins derived from many organisms even at the milligram scale. Among other applications it has the potential to supply the demand for a multitude of enzymes and enzyme variants facilitating in vitro metabolic engineering. This review will briefly address the recent achievements and limitations of cell free conversions. Especially, the requirements for reactor systems in cell free biotechnology, a currently underdeveloped field, are reviewed and some perspectives are given on how material sciences and biotechnology might be able to advance these new developments in the future.
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Affiliation(s)
- Steffen Rupp
- Department of Molecular Biotechnology, Fraunhofer IGB, Nobelstr. 12, 70569, Stuttgart, Germany,
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8
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Karig DK, Iyer S, Simpson ML, Doktycz MJ. Expression optimization and synthetic gene networks in cell-free systems. Nucleic Acids Res 2011; 40:3763-74. [PMID: 22180537 PMCID: PMC3333853 DOI: 10.1093/nar/gkr1191] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Synthetic biology offers great promise to a variety of applications through the forward engineering of biological function. Most efforts in this field have focused on employing living cells, yet cell-free approaches offer simpler and more flexible contexts. Here, we evaluate cell-free regulatory systems based on T7 promoter-driven expression by characterizing variants of TetR and LacI repressible T7 promoters in a cell-free context and examining sequence elements that determine expression efficiency. Using the resulting constructs, we then explore different approaches for composing regulatory systems, leading to the implementation of inducible negative feedback in Escherichia coli extracts and in the minimal PURE system, which consists of purified proteins necessary for transcription and translation. Despite the fact that negative feedback motifs are common and essential to many natural and engineered systems, this simple building block has not previously been implemented in a cell-free context. As a final step, we then demonstrate that the feedback systems developed using our cell-free approach can be implemented in live E. coli as well, illustrating the potential for using cell-free expression to fast track the development of live cell systems in synthetic biology. Our quantitative cell-free component characterizations and demonstration of negative feedback embody important steps on the path to harnessing biological function in a bottom-up fashion.
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Affiliation(s)
- David K Karig
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Bethel Valley Road, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
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9
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Ahn JH, Kang TJ, Kim DM. Tuning the expression level of recombinant proteins by modulating mRNA stability in a cell-free protein synthesis system. Biotechnol Bioeng 2008; 101:422-7. [DOI: 10.1002/bit.21884] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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10
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Rabinovich PM, Komarovskaya ME, Ye ZJ, Imai C, Campana D, Bahceci E, Weissman SM. Synthetic messenger RNA as a tool for gene therapy. Hum Gene Ther 2007; 17:1027-35. [PMID: 17007566 DOI: 10.1089/hum.2006.17.1027] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Transfection of human cells with DNA in biomedical applications carries the risk of insertional mutagenesis. Transfection with mRNA avoids this problem; however, in vitro production of mRNA, based on preliminary DNA template cloning in special vectors, is a laborious and time-consuming procedure. We report an efficient vectorfree method of mRNA production from polymerase chain reaction-generated DNA templates. For all cell types tested mRNA was transfected more readily than DNA, and its expression was highly uniform in cell populations. Even cell types relatively resistant to transfection with DNA could express transfected mRNA well. The level of mRNA expression could be controlled over a wide range by changing the amount of input RNA. Cells could be efficiently and simultaneously loaded with several different transcripts. To test a potential clinical application of this method, we transfected human T lymphocytes with mRNA encoding a chimeric immune receptor directed against CD19, a surface antigen widely expressed in leukemia and lymphoma. The transfected mRNA conferred powerful cytotoxicity to T cells against CD19+ targets from the same donor. These results demonstrate that this method can be applied to generate autologous T lymphocytes directed toward malignant cells.
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Affiliation(s)
- Peter M Rabinovich
- Department of Genetics, Yale University School of Medicine, New Haven, CT 06520, and Department of Hematology-Oncology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
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11
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Abstract
Protein synthesis in cell-free systems is an emerging technology already competing with in vivo expression methods. In this chapter the basic principles of continuous-exchange protein synthesizing systems, and protocols for Escherichia coli and wheat germ translation and transcription-translation systems are described. The ways to improve substrate supply in cell-free systems and mRNA design for eukaryotic system are discussed. Correct folding of the synthesized protein is demonstrated and discussed in detail.
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Affiliation(s)
- Vladimir A Shirokov
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow, Russia
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12
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Rabinovich PM, Komarovskaya ME, Ye ZJ, Imai C, Campana D, Bahceci E, Weissman SM. Synthetic Messenger RNA as a Tool for Gene Therapy. Hum Gene Ther 2006. [DOI: 10.1089/hum.2006.17.ft-249] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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14
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Kim TW, Kim DM, Choi CY. Rapid production of milligram quantities of proteins in a batch cell-free protein synthesis system. J Biotechnol 2006; 124:373-80. [PMID: 16487613 DOI: 10.1016/j.jbiotec.2005.12.030] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2005] [Revised: 12/05/2005] [Accepted: 12/23/2005] [Indexed: 11/19/2022]
Abstract
We developed a cell-free protein synthesis system that produces more than 1mg/ml of recombinant proteins in two hours. A basal system that supports the stable maintenance of ATP and amino acids was constructed by using high concentrations of CP (100 mM) and amino acids (3 mM). Approximately 0.6 mg/ml of protein was produced during the batch incubation of the basal system. We found that the accumulation of inorganic phosphate reduces the concentration of free magnesium ions and that there exists a critical concentration of magnesium at which the protein synthesis is halted. Based on this finding, we attempted to extend the duration of the protein synthesis by keeping the magnesium concentration sufficiently high throughout the reaction period. The protein synthesis reaction continued for at least 2 h when the reaction was repeatedly supplemented with magnesium, and approximately 1.2 mg/ml of active CAT or GFP was produced. The simple, fast, and highly productive cell-free protein synthesis system described herein should offer a versatile platform for the preparation of protein molecules in various post-genomic efforts.
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Affiliation(s)
- Tae-Wan Kim
- School of Chemical and Biological Engineering, College of Engineering, Seoul National University, Korea
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15
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Abstract
Continuous cell-free translation systems with perpetual supply of consumable substrates and removal of reaction products made the process of in vitro synthesis of individual proteins sustainable and productive. Improvements of cell-free reaction mixtures, including new ways for efficient energy generation, had an additional impact on progress in cell-free protein synthesis technology. The requirement for gene-product identification in genomic studies, the development of high-throughput structural proteomics, the need for protein engineering without cell constraints (including the use of unnatural amino acids), and the need to produce cytotoxic, poorly expressed and unstable proteins have caused increased interest in cell-free protein synthesis technologies for molecular biologists, biotechnologists and pharmacologists.
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Affiliation(s)
- Alexander S Spirin
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia.
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16
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Ali M, Suzuki H, Fukuba T, Jiang X, Nakano H, Yamane T. Improvements in the cell-free production of functional antibodies using cell extract from protease-deficient Escherichia coli mutant. J Biosci Bioeng 2005; 99:181-6. [PMID: 16233776 DOI: 10.1263/jbb.99.181] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2004] [Accepted: 11/22/2004] [Indexed: 11/17/2022]
Abstract
Expression of a functional antibody fragment (Fab) using an Escherichia coli cell-free expression system has been reported previously [Jiang et al., FEBS Lett., 514, 290-294 (2002)]. The low yield of the synthesized antibody, however, limits the usefulness of the cell-free expression system, partly due to the degradation of product by endogenous proteases from the E. coli extract. To determine which proteases are responsible for the degradation, we compared the expression of a 6D9 Fab fragment under conditions whereby several protease inhibitors were added into the cell-free system. The addition of serine protease inhibitor increased the amount of the Fab fragment, indicating that serine proteases caused the antibody degradation. Therefore, several serine protease-deficient mutants of E. coli BW25113 were constructed by targeted homologous recombination. The use of extract from a double protease-deficient mutant (DeltadegP-ompT) significantly increased the amount and antigen-binding activities of an anti-HSA scFv and a 6D9 Fab fragment. These results suggest that the DegP- and OmpT-deleted mutant is a useful source of S30 extract for the production or screening of antibodies using the cell-free expression system.
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Affiliation(s)
- Muhamad Ali
- Laboratory of Molecular Biotechnology, Graduate School of Biological and Agricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
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17
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Biocatalytic membrane reactor with continuous removal of organic acids by electrodialysis. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s0927-5193(03)80015-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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18
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Nakano H, Okumura R, Goto C, Yamane T. In vitro combinatorial mutagenesis of the 65th and 222nd positions of the green fluorescent protein ofAequarea victoria. BIOTECHNOL BIOPROC E 2002. [DOI: 10.1007/bf02932841] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Yang J, Koga Y, Nakano H, Yamane T. Modifying the chain-length selectivity of the lipase from Burkholderia cepacia KWI-56 through in vitro combinatorial mutagenesis in the substrate-binding site. Protein Eng Des Sel 2002; 15:147-52. [PMID: 11917151 DOI: 10.1093/protein/15.2.147] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The mature lipase of Burkholderia cepacia KWI-56 was synthesized in an enzymatically active form using an in vitro Escherichia coli S30 coupled transcription/translation system by expressing the mature lipase gene (rlip) in the presence of its specific activator. To investigate the substrate specificity of the lipase comprehensively, a large number of mutant lipases were constructed and analyzed in a high throughput manner by combining overlapping PCR and in vitro protein synthesis. In this paper, Phe119 and Leu167, which are located in the acyl portion of the substrate-binding pocket of the lipase of B.cepacia KWI-56, were substituted with six hydrophobic amino acid residues by the in vitro combinatorial mutagenesis. The wild-type and 35 mutant genes amplified by PCR were directly used as templates for the in vitro transcription/translation. The acyl chain-length selectivity of the in vitro expressed lipases against p-nitrophenyl butyrate, p-nitrophenyl caprylate and p-nitrophenyl palmitate, was compared by their relative hydrolysis rates. Two mutant lipases, L167V and F119A/L167M, which showed a significant shift in substrate selectivity were further expressed in vivo and refolded in vitro. It was found that L167V raised its preference for the short-chain ester, whereas F119A/L167M improved its selectivity for the long-chain ester.
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Affiliation(s)
- Junhao Yang
- Laboratory of Molecular Biotechnology, Graduate School of Biological and Agricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
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LIU YONGCHENG, YE JIANMING, LI YANBIN. A MEMBRANE SEPARATOR/BIOREACTOR COUPLED WITH ABSORBANCE MEASUREMENT FOR DETECTION OF Escherichia coli O157:H7. ACTA ACUST UNITED AC 2001. [DOI: 10.1111/j.1745-4581.2001.tb00232.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
Escherichia coli offers a means for the rapid and economical production of recombinant proteins. These advantages, coupled with a wealth of biochemical and genetic knowledge, have enabled the production of such economically sensitive products as insulin and bovine growth hormone. Although significant progress has been made in transcription, translation and secretion, one of the major challenges is obtaining the product in a soluble and bioactive form. Recent progress in oxidative cytoplasmic folding and cell-free protein synthesis offers attractive alternatives to standard expression methods.
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Affiliation(s)
- J R Swartz
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305-5025, USA.
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Dosage effect of minor arginyl- and isoleucyl-tRNAs on protein synthesis in an Escherichia coli in vitro coupled transcription/translation system. J Biosci Bioeng 2001. [DOI: 10.1016/s1389-1723(01)80111-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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23
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Yang J, Kobayashi K, Iwasaki Y, Nakano H, Yamane T. In vitro analysis of roles of a disulfide bridge and a calcium binding site in activation of Pseudomonas sp. strain KWI-56 lipase. J Bacteriol 2000; 182:295-302. [PMID: 10629173 PMCID: PMC94276 DOI: 10.1128/jb.182.2.295-302.2000] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The expression of lipase from Pseudomonas sp. strain KWI-56 (recently reclassified as Burkholderia cepacia) had been found to be dependent on an activator gene (act) downstream of its structural gene (lip). In this work, the mature lipase was synthesized in an enzymatically active form with a cell-free Escherichia coli S30 coupled transcription-translation system by expressing a recombinant lipase gene (rlip) encoding the mature lipase in the presence of its purified activator or by coexpression of rlip and act. The in vitro expression systems were used for studying the folding process of the lipase. The addition of dithiothreitol in the expression systems decreased the activity dramatically without affecting the synthesis level of the lipase, whereas the in vitro-synthesized active lipase was relatively stable even in the presence of dithiothreitol. This phenomenon was further investigated by constructing mutant lipase genes only in vitro by PCR without gene cloning. Replacements of cysteine residues (Cys190 and Cys270) forming a sole putative disulfide bond to serine residues decreased the lipase activity greatly, suggesting that the disulfide bond was essential for the proper folding of the lipase. In addition, replacing Asp242 and Asp288, which were deduced to be part of a Ca(2+) binding site, also greatly decreased the activities of the in vitro-synthesized lipases. The role of the Ca(2+) binding site in the activation of the lipase is also discussed.
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Affiliation(s)
- J Yang
- Laboratory of Molecular Biotechnology, Graduate School of Biological and Agricultural Sciences, Nagoya University, Chikusa-ku, Nagoya 464-8601, Japan
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