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Lee SJ, Kim DM. Cell-Free Synthesis: Expediting Biomanufacturing of Chemical and Biological Molecules. Molecules 2024; 29:1878. [PMID: 38675698 PMCID: PMC11054211 DOI: 10.3390/molecules29081878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Revised: 04/14/2024] [Accepted: 04/16/2024] [Indexed: 04/28/2024] Open
Abstract
The increasing demand for sustainable alternatives underscores the critical need for a shift away from traditional hydrocarbon-dependent processes. In this landscape, biomanufacturing emerges as a compelling solution, offering a pathway to produce essential chemical materials with significantly reduced environmental impacts. By utilizing engineered microorganisms and biomass as raw materials, biomanufacturing seeks to achieve a carbon-neutral footprint, effectively counteracting the carbon dioxide emissions associated with fossil fuel use. The efficiency and specificity of biocatalysts further contribute to lowering energy consumption and enhancing the sustainability of the production process. Within this context, cell-free synthesis emerges as a promising approach to accelerate the shift towards biomanufacturing. Operating with cellular machinery in a controlled environment, cell-free synthesis offers multiple advantages: it enables the rapid evaluation of biosynthetic pathways and optimization of the conditions for the synthesis of specific chemicals. It also holds potential as an on-demand platform for the production of personalized and specialized products. This review explores recent progress in cell-free synthesis, highlighting its potential to expedite the transformation of chemical processes into more sustainable biomanufacturing practices. We discuss how cell-free techniques not only accelerate the development of new bioproducts but also broaden the horizons for sustainable chemical production. Additionally, we address the challenges of scaling these technologies for commercial use and ensuring their affordability, which are critical for cell-free systems to meet the future demands of industries and fully realize their potential.
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Affiliation(s)
| | - Dong-Myung Kim
- Department of Chemical Engineering and Applied Chemistry, Chungnam National University, 99 Daehak-Ro, Daejeon 34134, Republic of Korea;
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2
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Qin Y, Ma X, Tao R, Du Y, Chen T. Synthesis, Reverse Transcription, Replication, and Inter-Transcription of 2'-Modified Nucleic Acids with Evolved Thermophilic Polymerases: Efforts toward Multidimensional Expansion of the Central Dogma. ACS Synth Biol 2023; 12:2616-2631. [PMID: 37646406 DOI: 10.1021/acssynbio.3c00213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
In the past decades, various xenobiotic nucleic acids (XNAs), including 2'-modified nucleic acids, have been developed as novel genetic materials and demonstrated great potential in synthetic biology and biotechnology. Enzymatic polymerization and replication of these artificial polymers are obviously the prerequisite to make full use of them, and DNA and RNA polymerases from different families have thus been extensively engineered for these purposes. However, the performance of engineered XNA polymerases is still far from satisfactory, especially in terms of the efficiency of synthesizing XNA with bigger lengths and the capability of directly replicating XNAs or transcribing one XNA to another. In this work, we tailored a mutant of Stoffel fragment of Taq DNA polymerase, SFM4-3, by engineering a key residue pair on the surfaces of fingers and thumb domains, and successfully obtained mutants with significantly enhanced efficiency for the synthesis of fully 2'-OMe-modified DNA with bigger lengths. Remarkably, we also found that these polymerase mutants are capable of synthesizing, reverse transcribing, and even replicating RNA and different fully 2'-modified XNAs, as well as transcribing one of these nucleic acids to another, with varied efficiencies. The application of these activities for producing DNA strands end-protected by XNA duplexes was then demonstrated. These results clearly suggest that the genetic information can be stored in and transmitted among DNA, RNA, and different 2'-modified XNAs with the assistance of polymerase mutants, and the central dogma of life can be expanded to higher dimensions via the development of XNAs together with engineering their polymerases.
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Affiliation(s)
- Yanjia Qin
- MOE International Joint Research Laboratory on Synthetic Biology and Medicines, School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, P. R. China
| | - Xingyun Ma
- MOE International Joint Research Laboratory on Synthetic Biology and Medicines, School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, P. R. China
| | - Rui Tao
- MOE International Joint Research Laboratory on Synthetic Biology and Medicines, School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, P. R. China
| | - Yuhui Du
- MOE International Joint Research Laboratory on Synthetic Biology and Medicines, School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, P. R. China
| | - Tingjian Chen
- MOE International Joint Research Laboratory on Synthetic Biology and Medicines, School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, P. R. China
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3
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Li J, Li P, Liu Q, Li J, Qi H. Translation initiation consistency between in vivo and in vitro bacterial protein expression systems. Front Bioeng Biotechnol 2023; 11:1201580. [PMID: 37304134 PMCID: PMC10248181 DOI: 10.3389/fbioe.2023.1201580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 05/17/2023] [Indexed: 06/13/2023] Open
Abstract
Strict on-demand control of protein synthesis is a crucial aspect of synthetic biology. The 5'-terminal untranslated region (5'-UTR) is an essential bacterial genetic element that can be designed for the regulation of translation initiation. However, there is insufficient systematical data on the consistency of 5'-UTR function among various bacterial cells and in vitro protein synthesis systems, which is crucial for the standardization and modularization of genetic elements in synthetic biology. Here, more than 400 expression cassettes comprising the GFP gene under the regulation of various 5'-UTRs were systematically characterized to evaluate the protein translation consistency in the two popular Escherichia coli strains of JM109 and BL21, as well as an in vitro protein expression system based on cell lysate. In contrast to the very strong correlation between the two cellular systems, the consistency between in vivo and in vitro protein translation was lost, whereby both in vivo and in vitro translation evidently deviated from the estimation of the standard statistical thermodynamic model. Finally, we found that the absence of nucleotide C and complex secondary structure in the 5'-UTR significantly improve the efficiency of protein translation, both in vitro and in vivo.
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Affiliation(s)
- Jiaojiao Li
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
- Frontier Science Center for Synthetic Biology (Ministry of Education), Tianjin University, Tianjin, China
| | - Peixian Li
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
- Frontier Science Center for Synthetic Biology (Ministry of Education), Tianjin University, Tianjin, China
| | - Qian Liu
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
- Frontier Science Center for Synthetic Biology (Ministry of Education), Tianjin University, Tianjin, China
| | - Jinjin Li
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
- Frontier Science Center for Synthetic Biology (Ministry of Education), Tianjin University, Tianjin, China
| | - Hao Qi
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
- Frontier Science Center for Synthetic Biology (Ministry of Education), Tianjin University, Tianjin, China
- Zhejiang Shaoxing Research Institute of Tianjin University, Shaoxing, China
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4
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Fochtman TJ, Oza JP. Established and Emerging Methods for Protecting Linear DNA in Cell-Free Expression Systems. Methods Protoc 2023; 6:mps6020036. [PMID: 37104018 PMCID: PMC10146267 DOI: 10.3390/mps6020036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 03/17/2023] [Accepted: 03/21/2023] [Indexed: 04/03/2023] Open
Abstract
Cell-free protein synthesis (CFPS) is a method utilized for producing proteins without the limits of cell viability. The plug-and-play utility of CFPS is a key advantage over traditional plasmid-based expression systems and is foundational to the potential of this biotechnology. A key limitation of CFPS is the varying stability of DNA types, limiting the effectiveness of cell-free protein synthesis reactions. Researchers generally rely on plasmid DNA for its ability to support robust protein expression in vitro. However, the overhead required to clone, propagate, and purify plasmids reduces the potential of CFPS for rapid prototyping. While linear templates overcome the limits of plasmid DNA preparation, linear expression templates (LETs) were under-utilized due to their rapid degradation in extract based CFPS systems, limiting protein synthesis. To reach the potential of CFPS using LETs, researchers have made notable progress toward protection and stabilization of linear templates throughout the reaction. The current advancements range from modular solutions, such as supplementing nuclease inhibitors and genome engineering to produce strains lacking nuclease activity. Effective application of LET protection techniques improves expression yields of target proteins to match that of plasmid-based expression. The outcome of LET utilization in CFPS is rapid design–build–test–learn cycles to support synthetic biology applications. This review describes the various protection mechanisms for linear expression templates, methodological insights for implementation, and proposals for continued efforts that may further advance the field.
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5
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Smith SA, Lindgren CM, Ebbert LE, Free TJ, Nelson JAD, Simonson KM, Hunt JP, Bundy BC. "Just add small molecules" cell-free protein synthesis: Combining DNA template and cell extract preparation into a single fermentation. Biotechnol Prog 2023:e3332. [PMID: 36799109 DOI: 10.1002/btpr.3332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/19/2023] [Accepted: 02/08/2023] [Indexed: 02/18/2023]
Abstract
Cell-free protein synthesis (CFPS) is a versatile biotechnology platform enabling a broad range of applications including clinical diagnostics, large-scale production of officinal therapeutics, small-scale on-demand production of personal magistral therapeutics, and exploratory research. The shelf stability and scalability of CFPS systems also have the potential to overcome cost and infrastructure challenges for distributing and using essential medical tests at home in both high- and low-income countries. However, CFPS systems are often more time-consuming and expensive to prepare than traditional in vivo systems, limiting their broader use. Much work has been done to lower CFPS costs by optimizing cell extract preparation, small molecule reagent recipes, and DNA template preparation. In order to further reduce reagent cost and preparation time, this work presents a CFPS system that does not require separately purified DNA template. Instead, a DNA plasmid encoding the recombinant protein is transformed into the cells used to make the extract, and the extract preparation process is modified to allow enough DNA to withstand homogenization-induced shearing. The finished extract contains sufficient levels of intact DNA plasmid for the CFPS system to operate. For a 10 mL scale CFPS system expressing recombinant sfGFP protein for a biosensor, this new system reduces reagent cost by more than half. This system is applied to a proof-of-concept glutamine sensor compatible with smartphone quantification to demonstrate its viability for further cost reduction and use in low-resource settings.
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Affiliation(s)
- Sydney A Smith
- Department of Chemical Engineering, Brigham Young University, Provo, Utah, USA
| | - Caleb M Lindgren
- Department of Chemical Engineering, Brigham Young University, Provo, Utah, USA
| | - Landon E Ebbert
- Department of Chemical Engineering, Brigham Young University, Provo, Utah, USA
| | - Tyler J Free
- Department of Chemical Engineering, Brigham Young University, Provo, Utah, USA
| | - J Andrew D Nelson
- Department of Chemical Engineering, Brigham Young University, Provo, Utah, USA
| | - Katelyn M Simonson
- Department of Chemical Engineering, Brigham Young University, Provo, Utah, USA
| | - J Porter Hunt
- Department of Chemical Engineering, Brigham Young University, Provo, Utah, USA
| | - Bradley C Bundy
- Department of Chemical Engineering, Brigham Young University, Provo, Utah, USA
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6
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Sánchez-Costa M, López-Gallego F. Solid-Phase Cell-Free Protein Synthesis and Its Applications in Biotechnology. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2023; 185:21-46. [PMID: 37306703 DOI: 10.1007/10_2023_226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Cell-free systems for the in vitro production of proteins have revolutionized the synthetic biology field. In the last decade, this technology is gaining momentum in molecular biology, biotechnology, biomedicine and even education. Materials science has burst into the field of in vitro protein synthesis to empower the value of existing tools and expand its applications. In this sense, the combination of solid materials (normally functionalized with different biomacromolecules) together with cell-free components has made this technology more versatile and robust. In this chapter, we discuss the combination of solid materials with DNA and transcription-translation machinery to synthesize proteins within compartments, to immobilize and purify in situ the nascent protein, to transcribe and transduce DNAs immobilized on solid surfaces, and the combination of all or some of these strategies.
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Affiliation(s)
- Mercedes Sánchez-Costa
- Heterogeneous Biocatalysis Laboratory, Center for Cooperative Research in Biomaterials (CIC biomaGUNE), Basque Research and Technology Alliance (BRTA), Donostia-San Sebastián, Spain
| | - Fernando López-Gallego
- Heterogeneous Biocatalysis Laboratory, Center for Cooperative Research in Biomaterials (CIC biomaGUNE), Basque Research and Technology Alliance (BRTA), Donostia-San Sebastián, Spain.
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7
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Liyanagedera SBW, Williams J, Wheatley JP, Biketova AY, Hasan M, Sagona AP, Purdy KJ, Puxty RJ, Feher T, Kulkarni V. SpyPhage: A Cell-Free TXTL Platform for Rapid Engineering of Targeted Phage Therapies. ACS Synth Biol 2022; 11:3330-3342. [PMID: 36194543 DOI: 10.1021/acssynbio.2c00244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The past decade has seen the emergence of multidrug resistant pathogens as a leading cause of death worldwide, reigniting interest in the field of phage therapy. Modern advances in the genetic engineering of bacteriophages have enabled several useful results including host range alterations, constitutive lytic growth, and control over phage replication. However, the slow licensing process of genetically modified organisms clearly inhibits the rapid therapeutic application of novel engineered variants necessary to fight mutant pathogens that emerge throughout the course of a pandemic. As a solution to this problem, we propose the SpyPhage system where a "scaffold" bacteriophage is engineered to incorporate a SpyTag moiety on its capsid head to enable rapid postsynthetic modification of their surfaces with SpyCatcher-fused therapeutic proteins. As a proof of concept, through CRISPR/Cas-facilitated phage engineering and whole genome assembly, we targeted a SpyTag capsid fusion to K1F, a phage targeting the pathogenic strain Escherichia coli K1. We demonstrate for the first time the cell-free assembly and decoration of the phage surface with two alternative fusion proteins, SpyCatcher-mCherry-EGF and SpyCatcher-mCherry-Rck, both of which facilitate the endocytotic uptake of the phages by a urinary bladder epithelial cell line. Overall, our work presents a cell-free phage production pipeline for the generation of multiple phenotypically distinct phages with a single underlying "scaffold" genotype. These phages could become the basis of next-generation phage therapies where the knowledge-based engineering of numerous phage variants would be quickly achievable without the use of live bacteria or the need to repeatedly license novel genetic alterations.
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Affiliation(s)
| | - Joshua Williams
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Joseph P Wheatley
- School of Engineering, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Alona Yu Biketova
- Institute of Biochemistry, Eötvös Lóránd Research Network, Szeged Biological Research Centre, Szeged 6726, Hungary.,Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond TW9 3AE, United Kingdom
| | - Muhammad Hasan
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Antonia P Sagona
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Kevin J Purdy
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Richard J Puxty
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Tamas Feher
- Institute of Biochemistry, Eötvös Lóránd Research Network, Szeged Biological Research Centre, Szeged 6726, Hungary
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8
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Pandi A, Diehl C, Yazdizadeh Kharrazi A, Scholz SA, Bobkova E, Faure L, Nattermann M, Adam D, Chapin N, Foroughijabbari Y, Moritz C, Paczia N, Cortina NS, Faulon JL, Erb TJ. A versatile active learning workflow for optimization of genetic and metabolic networks. Nat Commun 2022; 13:3876. [PMID: 35790733 PMCID: PMC9256728 DOI: 10.1038/s41467-022-31245-z] [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: 02/12/2022] [Accepted: 06/10/2022] [Indexed: 11/13/2022] Open
Abstract
Optimization of biological networks is often limited by wet lab labor and cost, and the lack of convenient computational tools. Here, we describe METIS, a versatile active machine learning workflow with a simple online interface for the data-driven optimization of biological targets with minimal experiments. We demonstrate our workflow for various applications, including cell-free transcription and translation, genetic circuits, and a 27-variable synthetic CO2-fixation cycle (CETCH cycle), improving these systems between one and two orders of magnitude. For the CETCH cycle, we explore 1025 conditions with only 1,000 experiments to yield the most efficient CO2-fixation cascade described to date. Beyond optimization, our workflow also quantifies the relative importance of individual factors to the performance of a system identifying unknown interactions and bottlenecks. Overall, our workflow opens the way for convenient optimization and prototyping of genetic and metabolic networks with customizable adjustments according to user experience, experimental setup, and laboratory facilities. Optimization of biological networks is often limited by wet lab labor and cost, and the lack of convenient computational tools. Here, aimed at democratization and standardization, the authors describe METIS, a modular and versatile active machine learning workflow with a simple online interface for the optimization of biological target functions with minimal experimental datasets.
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Affiliation(s)
- Amir Pandi
- Department of Biochemistry & Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.
| | - Christoph Diehl
- Department of Biochemistry & Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | | | - Scott A Scholz
- Department of Biochemistry & Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Elizaveta Bobkova
- Department of Biochemistry & Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Léon Faure
- Micalis Institute, INRAE, AgroParisTech, University of Paris-Saclay, Jouy-en-Josas, France
| | - Maren Nattermann
- Department of Biochemistry & Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - David Adam
- Department of Biochemistry & Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Nils Chapin
- Department of Biochemistry & Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Yeganeh Foroughijabbari
- Department of Biochemistry & Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Charles Moritz
- Department of Biochemistry & Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Nicole Paczia
- Core Facility for Metabolomics and Small Molecule Mass Spectrometry, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Niña Socorro Cortina
- Department of Biochemistry & Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.,LiVeritas Biosciences, Inc., 432N Canal St.; Ste. 20, South San Francisco, CA, 94080, USA
| | - Jean-Loup Faulon
- Micalis Institute, INRAE, AgroParisTech, University of Paris-Saclay, Jouy-en-Josas, France.,Genomique Metabolique, Genoscope, Institut Francois Jacob, CEA, CNRS, Univ Evry, University of Paris-Saclay, Evry, France.,Manchester Institute of Biotechnology, SYNBIOCHEM center, School of Chemistry, The University of Manchester, Manchester, UK
| | - Tobias J Erb
- Department of Biochemistry & Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany. .,SYNMIKRO Center of Synthetic Microbiology, Marburg, Germany.
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9
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Toft CJ, Sorenson AE, Schaeffer PM. Rise of the terminator protein tus: A versatile tool in the biotechnologist's toolbox. Anal Chim Acta 2022; 1213:339946. [DOI: 10.1016/j.aca.2022.339946] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/10/2022] [Accepted: 05/12/2022] [Indexed: 02/07/2023]
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10
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Sakai A, Deich CR, Nelissen FHT, Jonker AJ, Bittencourt DMDC, Kempes CP, Wise KS, Heus HA, Huck WTS, Adamala KP, Glass JI. Traditional Protocols and Optimization Methods Lead to Absent Expression in a Mycoplasma Cell-Free Gene Expression Platform. Synth Biol (Oxf) 2022; 7:ysac008. [PMID: 35774105 PMCID: PMC9239315 DOI: 10.1093/synbio/ysac008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 04/11/2022] [Accepted: 05/20/2022] [Indexed: 11/23/2022] Open
Abstract
Cell-free expression (CFE) systems are one of the main platforms for building synthetic cells. A major drawback is the orthogonality of cell-free systems across species. To generate a CFE system compatible with recently established minimal cell constructs, we attempted to optimize a Mycoplasma bacterium-based CFE system using lysates of the genome-minimized cell JCVI-syn3A (Syn3A) and its close phylogenetic relative Mycoplasma capricolum (Mcap). To produce mycoplasma-derived crude lysates, we systematically tested methods commonly used for bacteria, based on the S30 protocol of Escherichia coli. Unexpectedly, after numerous attempts to optimize lysate production methods or composition of feeding buffer, none of the Mcap or Syn3A lysates supported cell-free gene expression. Only modest levels of in vitro transcription of RNA aptamers were observed. While our experimental systems were intended to perform transcription and translation, our assays focused on RNA. Further investigations identified persistently high ribonuclease (RNase) activity in all lysates, despite removal of recognizable nucleases from the respective genomes and attempts to inhibit nuclease activities in assorted CFE preparations. An alternative method using digitonin to permeabilize the mycoplasma cell membrane produced a lysate with diminished RNase activity yet still was unable to support cell-free gene expression. We found that intact mycoplasma cells poisoned E. coli cell-free extracts by degrading ribosomal RNAs, indicating that the mycoplasma cells, even the minimal cell, have a surface-associated RNase activity. However, it is not clear which gene encodes the RNase. This work summarizes attempts to produce mycoplasma-based CFE and serves as a cautionary tale for researchers entering this field.
Graphical Abstract
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Affiliation(s)
- Andrei Sakai
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, Nijmegen, 6525 AJ, The Netherlands
| | - Christopher R Deich
- Department of Genetics, Cell Biology and Development, University of Minnesota, 420 Washington Avenue SE, Minneapolis, MN 55455, USA
| | - Frank H T Nelissen
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, Nijmegen, 6525 AJ, The Netherlands
| | - Aafke J Jonker
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, Nijmegen, 6525 AJ, The Netherlands
| | - Daniela M de C Bittencourt
- The J. Craig Venter Institute, 4120 Capricorn Lane, La Jolla, CA 92037, USA
- Embrapa Genetic Resources and Biotechnology/National Institute of Science and Technology - Synthetic Biology, Parque Estação Biológica, PqEB, Av. W5 Norte (final), Brasília, DF, 70770-917, Brazil, Norte (final), Brasília, DF, 70770-917, Brazil
| | | | - Kim S Wise
- The J. Craig Venter Institute, 4120 Capricorn Lane, La Jolla, CA 92037, USA
| | - Hans A Heus
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, Nijmegen, 6525 AJ, The Netherlands
| | - Wilhelm T S Huck
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, Nijmegen, 6525 AJ, The Netherlands
| | - Katarzyna P Adamala
- Department of Genetics, Cell Biology and Development, University of Minnesota, 420 Washington Avenue SE, Minneapolis, MN 55455, USA
| | - John I Glass
- The J. Craig Venter Institute, 4120 Capricorn Lane, La Jolla, CA 92037, USA
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11
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Guzman-Chavez F, Arce A, Adhikari A, Vadhin S, Pedroza-Garcia JA, Gandini C, Ajioka JW, Molloy J, Sanchez-Nieto S, Varner JD, Federici F, Haseloff J. Constructing Cell-Free Expression Systems for Low-Cost Access. ACS Synth Biol 2022; 11:1114-1128. [PMID: 35259873 PMCID: PMC9098194 DOI: 10.1021/acssynbio.1c00342] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Indexed: 11/29/2022]
Abstract
Cell-free systems for gene expression have gained attention as platforms for the facile study of genetic circuits and as highly effective tools for teaching. Despite recent progress, the technology remains inaccessible for many in low- and middle-income countries due to the expensive reagents required for its manufacturing, as well as specialized equipment required for distribution and storage. To address these challenges, we deconstructed processes required for cell-free mixture preparation and developed a set of alternative low-cost strategies for easy production and sharing of extracts. First, we explored the stability of cell-free reactions dried through a low-cost device based on silica beads, as an alternative to commercial automated freeze dryers. Second, we report the positive effect of lactose as an additive for increasing protein synthesis in maltodextrin-based cell-free reactions using either circular or linear DNA templates. The modifications were used to produce active amounts of two high-value reagents: the isothermal polymerase Bst and the restriction enzyme BsaI. Third, we demonstrated the endogenous regeneration of nucleoside triphosphates and synthesis of pyruvate in cell-free systems (CFSs) based on phosphoenol pyruvate (PEP) and maltodextrin (MDX). We exploited this novel finding to demonstrate the use of a cell-free mixture completely free of any exogenous nucleotide triphosphates (NTPs) to generate high yields of sfGFP expression. Together, these modifications can produce desiccated extracts that are 203-424-fold cheaper than commercial versions. These improvements will facilitate wider use of CFS for research and education purposes.
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Affiliation(s)
| | - Anibal Arce
- ANID
− Millennium Institute for Integrative Biology (iBio), FONDAP
Center for Genome Regulation, Institute for Biological and Medical
Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago 8330005, Chile
| | - Abhinav Adhikari
- Robert
Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Sandra Vadhin
- Robert
Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Jose Antonio Pedroza-Garcia
- Department
of Biochemistry, Faculty of Chemistry, National
Autonomous University of Mexico (UNAM), 04510 Mexico City, Mexico
| | - Chiara Gandini
- Department
of Chemical Engineering and Biotechnology, University of Cambridge, CB3 0FD Cambridge, U.K.
| | - Jim W. Ajioka
- Department
of Pathology, University of Cambridge, Tennis Court Road, CB2 1QP Cambridge, U.K.
| | - Jenny Molloy
- Department
of Chemical Engineering and Biotechnology, University of Cambridge, CB3 0FD Cambridge, U.K.
| | - Sobeida Sanchez-Nieto
- Department
of Biochemistry, Faculty of Chemistry, National
Autonomous University of Mexico (UNAM), 04510 Mexico City, Mexico
| | - Jeffrey D. Varner
- Robert
Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Fernan Federici
- ANID
− Millennium Institute for Integrative Biology (iBio), FONDAP
Center for Genome Regulation, Institute for Biological and Medical
Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago 8330005, Chile
| | - Jim Haseloff
- Department
of Plant Sciences, University of Cambridge, CB2 3EA Cambridge, U.K.
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12
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Xu H, Yang C, Tian X, Chen Y, Liu WQ, Li J. Regulatory Part Engineering for High-Yield Protein Synthesis in an All- Streptomyces-Based Cell-Free Expression System. ACS Synth Biol 2022; 11:570-578. [PMID: 35129330 DOI: 10.1021/acssynbio.1c00587] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Streptomyces-based cell-free expression systems have been developed to meet the demand for synthetic biology applications. However, protein yields from the previous Streptomyces systems are relatively low, and there is a serious limitation of available genetic tools such as plasmids for gene (co)expression. Here, we sought to expand the plasmid toolkit with a focus on the enhancement of protein production. By screening native promoters and ribosome binding sites, we were able to construct a panel of plasmids with different abilities for protein synthesis, which covered a nearly 3-fold range of protein yields. Using the most efficient plasmid, the protein yield reached up to a maximum value of 515.7 ± 25.3 μg/mL. With the plasmid toolkit, we anticipate that our Streptomyces cell-free system will offer great opportunities for cell-free synthetic biology applications such as in vitro biosynthesis of valuable natural products when cell-based systems remain difficult or not amenable.
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Affiliation(s)
- Huiling Xu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Chen Yang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Xintong Tian
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yilin Chen
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Wan-Qiu Liu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Jian Li
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
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13
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Batista AC, Levrier A, Soudier P, Voyvodic PL, Achmedov T, Reif-Trauttmansdorff T, DeVisch A, Cohen-Gonsaud M, Faulon JL, Beisel CL, Bonnet J, Kushwaha M. Differentially Optimized Cell-Free Buffer Enables Robust Expression from Unprotected Linear DNA in Exonuclease-Deficient Extracts. ACS Synth Biol 2022; 11:732-746. [PMID: 35034449 DOI: 10.1021/acssynbio.1c00448] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The use of linear DNA templates in cell-free systems promises to accelerate the prototyping and engineering of synthetic gene circuits. A key challenge is that linear templates are rapidly degraded by exonucleases present in cell extracts. Current approaches tackle the problem by adding exonuclease inhibitors and DNA-binding proteins to protect the linear DNA, requiring additional time- and resource-intensive steps. Here, we delete the recBCD exonuclease gene cluster from the Escherichia coli BL21 genome. We show that the resulting cell-free systems, with buffers optimized specifically for linear DNA, enable near-plasmid levels of expression from σ70 promoters in linear DNA templates without employing additional protection strategies. When using linear or plasmid DNA templates at the buffer calibration step, the optimal potassium glutamate concentrations obtained when using linear DNA were consistently lower than those obtained when using plasmid DNA for the same extract. We demonstrate the robustness of the exonuclease deficient extracts across seven different batches and a wide range of experimental conditions across two different laboratories. Finally, we illustrate the use of the ΔrecBCD extracts for two applications: toehold switch characterization and enzyme screening. Our work provides a simple, efficient, and cost-effective solution for using linear DNA templates in cell-free systems and highlights the importance of specifically tailoring buffer composition for the final experimental setup. Our data also suggest that similar exonuclease deletion strategies can be applied to other species suitable for cell-free synthetic biology.
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Affiliation(s)
- Angelo Cardoso Batista
- Université Paris-Saclay, INRAe, AgroParisTech, Micalis Institute, 78352 Jouy-en-Josas, France
| | - Antoine Levrier
- Centre de Biochimie Structurale, INSERM U1054, CNRS UMR 5048, University of Montpellier, 34090 Montpellier, France
| | - Paul Soudier
- Université Paris-Saclay, INRAe, AgroParisTech, Micalis Institute, 78352 Jouy-en-Josas, France
- Centre de Biochimie Structurale, INSERM U1054, CNRS UMR 5048, University of Montpellier, 34090 Montpellier, France
| | - Peter L. Voyvodic
- Centre de Biochimie Structurale, INSERM U1054, CNRS UMR 5048, University of Montpellier, 34090 Montpellier, France
| | - Tatjana Achmedov
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz-Centre for Infection Research (HZI), 97080 Würzburg, Germany
| | | | - Angelique DeVisch
- Centre de Biochimie Structurale, INSERM U1054, CNRS UMR 5048, University of Montpellier, 34090 Montpellier, France
| | - Martin Cohen-Gonsaud
- Centre de Biochimie Structurale, INSERM U1054, CNRS UMR 5048, University of Montpellier, 34090 Montpellier, France
| | - Jean-Loup Faulon
- Université Paris-Saclay, INRAe, AgroParisTech, Micalis Institute, 78352 Jouy-en-Josas, France
| | - Chase L. Beisel
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz-Centre for Infection Research (HZI), 97080 Würzburg, Germany
- Medical Faculty, University of Würzburg, 97080 Würzburg, Germany
| | - Jerome Bonnet
- Centre de Biochimie Structurale, INSERM U1054, CNRS UMR 5048, University of Montpellier, 34090 Montpellier, France
| | - Manish Kushwaha
- Université Paris-Saclay, INRAe, AgroParisTech, Micalis Institute, 78352 Jouy-en-Josas, France
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14
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Beabout K, Bernhards CB, Thakur M, Turner KB, Cole SD, Walper SA, Chávez JL, Lux MW. Optimization of Heavy Metal Sensors Based on Transcription Factors and Cell-Free Expression Systems. ACS Synth Biol 2021; 10:3040-3054. [PMID: 34723503 DOI: 10.1021/acssynbio.1c00331] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Many bacterial mechanisms for highly specific and sensitive detection of heavy metals and other hazards have been reengineered to serve as sensors. In some cases, these sensors have been implemented in cell-free expression systems, enabling easier design optimization and deployment in low-resource settings through lyophilization. Here, we apply the advantages of cell-free expression systems to optimize sensors based on three separate bacterial response mechanisms for arsenic, cadmium, and mercury. We achieved detection limits below the World Health Organization-recommended levels for arsenic and mercury and below the short-term US Military Exposure Guideline levels for all three. The optimization of each sensor was approached differently, leading to observations useful for the development of future sensors: (1) there can be a strong dependence of specificity on the particular cell-free expression system used, (2) tuning of relative concentrations of the sensing and reporter elements improves sensitivity, and (3) sensor performance can vary significantly with linear vs plasmid DNA. In addition, we show that simply combining DNA for the three sensors into a single reaction enables detection of each target heavy metal without any further optimization. This combined approach could lead to sensors that detect a range of hazards at once, such as a panel of water contaminants or all known variants of a target virus. For low-resource settings, such "all-hazard" sensors in a cheap, easy-to-use format could have high utility.
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Affiliation(s)
- Kathryn Beabout
- UES, Inc., Dayton, Ohio 45432, United States
- Air Force Research Laboratory, 711th Human Performance Wing, Wright-Patterson Air Force Base, Dayton, Ohio 45433, United States
| | - Casey B. Bernhards
- Excet, Inc., 6225 Brandon Avenue #360, Springfield, Virginia 22150, United States
- U.S. Army Combat Capabilities Development Command Chemical Biological Center, 8198 Blackhawk Road, Aberdeen Proving Ground, Maryland 21010, United States
| | - Meghna Thakur
- Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, D.C. 20375, United States
- College of Science, George Mason University, Fairfax, Virginia 22030, United States
| | - Kendrick B. Turner
- Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, D.C. 20375, United States
| | - Stephanie D. Cole
- U.S. Army Combat Capabilities Development Command Chemical Biological Center, 8198 Blackhawk Road, Aberdeen Proving Ground, Maryland 21010, United States
| | - Scott A. Walper
- Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, D.C. 20375, United States
| | - Jorge L. Chávez
- Air Force Research Laboratory, 711th Human Performance Wing, Wright-Patterson Air Force Base, Dayton, Ohio 45433, United States
| | - Matthew W. Lux
- U.S. Army Combat Capabilities Development Command Chemical Biological Center, 8198 Blackhawk Road, Aberdeen Proving Ground, Maryland 21010, United States
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15
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McSweeney MA, Styczynski MP. Effective Use of Linear DNA in Cell-Free Expression Systems. Front Bioeng Biotechnol 2021; 9:715328. [PMID: 34354989 PMCID: PMC8329657 DOI: 10.3389/fbioe.2021.715328] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 07/06/2021] [Indexed: 12/27/2022] Open
Abstract
Cell-free expression systems (CFEs) are cutting-edge research tools used in the investigation of biological phenomena and the engineering of novel biotechnologies. While CFEs have many benefits over in vivo protein synthesis, one particularly significant advantage is that CFEs allow for gene expression from both plasmid DNA and linear expression templates (LETs). This is an important and impactful advantage because functional LETs can be efficiently synthesized in vitro in a few hours without transformation and cloning, thus expediting genetic circuit prototyping and allowing expression of toxic genes that would be difficult to clone through standard approaches. However, native nucleases present in the crude bacterial lysate (the basis for the most affordable form of CFEs) quickly degrade LETs and limit expression yield. Motivated by the significant benefits of using LETs in lieu of plasmid templates, numerous methods to enhance their stability in lysate-based CFEs have been developed. This review describes approaches to LET stabilization used in CFEs, summarizes the advancements that have come from using LETs with these methods, and identifies future applications and development goals that are likely to be impactful to the field. Collectively, continued improvement of LET-based expression and other linear DNA tools in CFEs will help drive scientific discovery and enable a wide range of applications, from diagnostics to synthetic biology research tools.
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Affiliation(s)
- Megan A McSweeney
- Georgia Institute of Technology, School of Chemical & Biomolecular Engineering, Atlanta, GA, United States
| | - Mark P Styczynski
- Georgia Institute of Technology, School of Chemical & Biomolecular Engineering, Atlanta, GA, United States
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16
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Norouzi M, Panfilov S, Pardee K. High-Efficiency Protection of Linear DNA in Cell-Free Extracts from Escherichia coli and Vibrio natriegens. ACS Synth Biol 2021; 10:1615-1624. [PMID: 34161082 DOI: 10.1021/acssynbio.1c00110] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The field of cell-free synthetic biology is an emerging branch of engineered biology that allows for rapid prototyping of biological designs and, in its own right, is becoming a venue for the in vitro operation of gene circuit-based sensors and biomanufacturing. To date, the related DNA encoded tools that operate in cell-free reactions have primarily relied on plasmid DNA inputs, as linear templates are highly susceptible to degradation by exonucleases present in cell-free extracts. This incompatibility has precluded significant throughput, time and cost benefits that could be gained with the use of linear DNA in the cell-free expression workflow. Here to tackle this limitation, we report that terminal incorporation of Ter binding sites for the DNA-binding protein Tus enables highly efficient protection of linear expression templates encoding mCherry and deGFP. In Escherichia coli extracts, our method compares favorably with the previously reported GamS-mediated protection scheme. Importantly, we extend the Tus-Ter system to Vibrio natriegens extracts, and demonstrate that this simple and easily implemented method can enable an unprecedented plasmid-level expression from linear templates in this emerging chassis organism.
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Affiliation(s)
- Masoud Norouzi
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada
| | - Sabina Panfilov
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada
| | - Keith Pardee
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario M5S 3G8, Canada
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17
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Blum SM, Lee MS, Mgboji GE, Funk VL, Beabout K, Harbaugh SV, Roth PA, Liem AT, Miklos AE, Emanuel PA, Walper SA, Chávez JL, Lux MW. Impact of Porous Matrices and Concentration by Lyophilization on Cell-Free Expression. ACS Synth Biol 2021; 10:1116-1131. [PMID: 33843211 DOI: 10.1021/acssynbio.0c00634] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Cell-free expression systems have drawn increasing attention as a tool to achieve complex biological functions outside of the cell. Several applications of the technology involve the delivery of functionality to challenging environments, such as field-forward diagnostics or point-of-need manufacturing of pharmaceuticals. To achieve these goals, cell-free reaction components are preserved using encapsulation or lyophilization methods, both of which often involve an embedding of components in porous matrices like paper or hydrogels. Previous work has shown a range of impacts of porous materials on cell-free expression reactions. Here, we explored a panel of 32 paperlike materials and 5 hydrogel materials for the impact on reaction performance. The screen included a tolerance to lyophilization for reaction systems based on both cell lysates and purified expression components. For paperlike materials, we found that (1) materials based on synthetic polymers were mostly incompatible with cell-free expression, (2) lysate-based reactions were largely insensitive to the matrix for cellulosic and microfiber materials, and (3) purified systems had an improved performance when lyophilized in cellulosic but not microfiber matrices. The impact of hydrogel materials ranged from completely inhibitory to a slight enhancement. The exploration of modulating the rehydration volume of lyophilized reactions yielded reaction speed increases using an enzymatic colorimetric reporter of up to twofold with an optimal ratio of 2:1 lyophilized reaction to rehydration volume for the lysate system and 1.5:1 for the purified system. The effect was independent of the matrices assessed. Testing with a fluorescent nonenzymatic reporter and no matrix showed similar improvements in both yields and reaction speeds for the lysate system and yields but not reaction speeds for the purified system. We finally used these observations to show an improved performance of two sensors that span reaction types, matrix, and reporters. In total, these results should enhance efforts to develop field-forward applications of cell-free expression systems.
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Affiliation(s)
- Steven M. Blum
- United States Army Combat Capabilities Development Command Chemical Biological Center. 8198 Blackhawk Road, APG, Aberdeen, Maryland 21010, United States
| | - Marilyn S. Lee
- United States Army Combat Capabilities Development Command Chemical Biological Center. 8198 Blackhawk Road, APG, Aberdeen, Maryland 21010, United States
| | - Glory E. Mgboji
- United States Army Combat Capabilities Development Command Chemical Biological Center. 8198 Blackhawk Road, APG, Aberdeen, Maryland 21010, United States
- Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee 37830-6209, United States
| | - Vanessa L. Funk
- United States Army Combat Capabilities Development Command Chemical Biological Center. 8198 Blackhawk Road, APG, Aberdeen, Maryland 21010, United States
| | - Kathryn Beabout
- UES, Inc., Dayton, Ohio 45432, United States
- 711th Human Performance Wing, Air Force Research Laboratory, Wright-Patterson Air Force Base, Ohio 45433, United States
| | - Svetlana V. Harbaugh
- 711th Human Performance Wing, Air Force Research Laboratory, Wright-Patterson Air Force Base, Ohio 45433, United States
| | - Pierce A. Roth
- United States Army Combat Capabilities Development Command Chemical Biological Center. 8198 Blackhawk Road, APG, Aberdeen, Maryland 21010, United States
- DCS Corporation, 4696 Millenium Drive, Suite 450, Belcamp, Maryland 21017, United States
| | - Alvin T. Liem
- United States Army Combat Capabilities Development Command Chemical Biological Center. 8198 Blackhawk Road, APG, Aberdeen, Maryland 21010, United States
- DCS Corporation, 4696 Millenium Drive, Suite 450, Belcamp, Maryland 21017, United States
| | - Aleksandr E. Miklos
- United States Army Combat Capabilities Development Command Chemical Biological Center. 8198 Blackhawk Road, APG, Aberdeen, Maryland 21010, United States
| | - Peter A. Emanuel
- United States Army Combat Capabilities Development Command Chemical Biological Center. 8198 Blackhawk Road, APG, Aberdeen, Maryland 21010, United States
| | - Scott A. Walper
- Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, District of Columbia 20375, United States
| | - Jorge Luis Chávez
- 711th Human Performance Wing, Air Force Research Laboratory, Wright-Patterson Air Force Base, Ohio 45433, United States
| | - Matthew W. Lux
- United States Army Combat Capabilities Development Command Chemical Biological Center. 8198 Blackhawk Road, APG, Aberdeen, Maryland 21010, United States
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18
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Chen X, Lu Y. In silico Design of Linear DNA for Robust Cell-Free Gene Expression. Front Bioeng Biotechnol 2021; 9:670341. [PMID: 34095101 PMCID: PMC8169995 DOI: 10.3389/fbioe.2021.670341] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Accepted: 04/06/2021] [Indexed: 12/25/2022] Open
Abstract
Cell-free gene expression systems with linear DNA expression templates (LDETs) have been widely applied in artificial cells, biochips, and high-throughput screening. However, due to the degradation caused by native nucleases in cell extracts, the transcription with linear DNA templates is weak, thereby resulting in low protein expression level, which greatly limits the development of cell-free systems using linear DNA templates. In this study, the protective sequences for stabilizing linear DNA and the transcribed mRNAs were rationally designed according to nucleases' action mechanism, whose effectiveness was evaluated through computer simulation and cell-free gene expression. The cell-free experiment results indicated that, with the combined protection of designed sequence and GamS protein, the protein expression of LDET-based cell-free systems could reach the same level as plasmid-based cell-free systems. This study would potentially promote the development of the LDET-based cell-free gene expression system for broader applications.
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Affiliation(s)
- Xinjie Chen
- Key Laboratory of Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing, China
| | - Yuan Lu
- Key Laboratory of Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing, China
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