1
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Bartsch T, Lütz S, Rosenthal K. Cell-free protein synthesis with technical additives - expanding the parameter space of in vitro gene expression. Beilstein J Org Chem 2024; 20:2242-2253. [PMID: 39286794 PMCID: PMC11403795 DOI: 10.3762/bjoc.20.192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2024] [Accepted: 08/22/2024] [Indexed: 09/19/2024] Open
Abstract
Biocatalysis has established itself as a successful tool in organic synthesis. A particularly fast technique for screening enzymes is the in vitro expression or cell-free protein synthesis (CFPS). The system is based on the transcription and translation machinery of an extract-donating organism to which substrates such as nucleotides and amino acids, as well as energy molecules, salts, buffer, etc., are added. After successful protein synthesis, further substrates can be added for an enzyme activity assay. Although mimicking of cell-like conditions is an approach for optimization, the physical and chemical properties of CFPS are not well described yet. To date, standard conditions have mainly been used for CFPS, with little systematic testing of whether conditions closer to intracellular conditions in terms of viscosity, macromolecules, inorganic ions, osmolarity, or water content are advantageous. Also, very few non-physiological conditions have been tested to date that would expand the parameter space in which CFPS can be performed. In this study, the properties of an Escherichia coli extract-based CFPS system are evaluated, and the parameter space is extended to high viscosities, concentrations of inorganic ion and osmolarity using ten different technical additives including organic solvents, polymers, and salts. It is shown that the synthesis of two model proteins, namely superfolder GFP (sfGFP) and the enzyme truncated human cyclic GMP-AMP synthase fused to sfGFP (thscGAS-sfGFP), is very robust against most of the tested additives.
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Affiliation(s)
- Tabea Bartsch
- Department of Biochemical and Chemical Engineering, TU Dortmund University, Emil-Figge-Straße 66, 44227 Dortmund, Germany
| | - Stephan Lütz
- Department of Biochemical and Chemical Engineering, TU Dortmund University, Emil-Figge-Straße 66, 44227 Dortmund, Germany
| | - Katrin Rosenthal
- School of Science, Constructor University, Campus Ring 6, 28759 Bremen, Germany
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2
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Kubyshkin V, Rubini M. Proline Analogues. Chem Rev 2024; 124:8130-8232. [PMID: 38941181 DOI: 10.1021/acs.chemrev.4c00007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/30/2024]
Abstract
Within the canonical repertoire of the amino acid involved in protein biogenesis, proline plays a unique role as an amino acid presenting a modified backbone rather than a side-chain. Chemical structures that mimic proline but introduce changes into its specific molecular features are defined as proline analogues. This review article summarizes the existing chemical, physicochemical, and biochemical knowledge about this peculiar family of structures. We group proline analogues from the following compounds: substituted prolines, unsaturated and fused structures, ring size homologues, heterocyclic, e.g., pseudoproline, and bridged proline-resembling structures. We overview (1) the occurrence of proline analogues in nature and their chemical synthesis, (2) physicochemical properties including ring conformation and cis/trans amide isomerization, (3) use in commercial drugs such as nirmatrelvir recently approved against COVID-19, (4) peptide and protein synthesis involving proline analogues, (5) specific opportunities created in peptide engineering, and (6) cases of protein engineering with the analogues. The review aims to provide a summary to anyone interested in using proline analogues in systems ranging from specific biochemical setups to complex biological systems.
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Affiliation(s)
| | - Marina Rubini
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland
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3
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Hejazi S, Ahsan A, Kashani M, Reuel NF. Amplified DNA Heterogeneity Assessment with Oxford Nanopore Sequencing Applied to Cell Free Expression Templates. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.02.597048. [PMID: 38895213 PMCID: PMC11185537 DOI: 10.1101/2024.06.02.597048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
In this work, Oxford Nanopore sequencing is tested as an accessible method for quantifying heterogeneity of amplified DNA. This method enables rapid quantification of deletions, insertions, and substitutions, the probability of each mutation error, and their locations in the replicated sequences. Amplification techniques tested were conventional polymerase chain reaction (PCR) with varying levels of polymerase fidelity (OneTaq, Phusion, and Q5) as well as rolling circle amplification (RCA) with Phi29 polymerase. Plasmid amplification using bacteria was also assessed. By analyzing the distribution of errors in a large set of sequences for each sample, we examined the heterogeneity and mode of errors in each sample. This analysis revealed that Q5 and Phusion polymerases exhibited the lowest error rates observed in the amplified DNA. As a secondary validation, we analyzed the emission spectra of sfGFP fluorescent proteins synthesized with amplified DNA using cell free expression. Error-prone polymerase chain reactions confirmed the dependency of reporter protein emission spectra peak broadness to DNA error rates. The presented nanopore sequencing methods serve as a roadmap to quantify the accuracy of other gene amplification techniques, as they are discovered, enabling more homogenous cell-free expression of desired proteins.
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Affiliation(s)
- Sepehr Hejazi
- Chemical and Biological Engineering - Iowa State University, 618 Bissell Rd, Ames, IA 50011
| | - Afrin Ahsan
- Chemical and Biological Engineering - Iowa State University, 618 Bissell Rd, Ames, IA 50011
| | - Mohammad Kashani
- Electrical and Computer Engineering - Iowa State University, 618 Bissell Rd, Ames, IA 50011
| | - Nigel F Reuel
- Chemical and Biological Engineering - Iowa State University, 618 Bissell Rd, Ames, IA 50011
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4
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Enninful GN, Kuppusamy R, Tiburu EK, Kumar N, Willcox MDP. Non-canonical amino acid bioincorporation into antimicrobial peptides and its challenges. J Pept Sci 2024; 30:e3560. [PMID: 38262069 DOI: 10.1002/psc.3560] [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] [Received: 06/06/2023] [Revised: 10/01/2023] [Accepted: 11/14/2023] [Indexed: 01/25/2024]
Abstract
The rise of antimicrobial resistance and multi-drug resistant pathogens has necessitated explorations for novel antibiotic agents as the discovery of conventional antibiotics is becoming economically less viable and technically more challenging for biopharma. Antimicrobial peptides (AMPs) have emerged as a promising alternative because of their particular mode of action, broad spectrum and difficulty that microbes have in becoming resistant to them. The AMPs bacitracin, gramicidin, polymyxins and daptomycin are currently used clinically. However, their susceptibility to proteolytic degradation, toxicity profile, and complexities in large-scale manufacture have hindered their development. To improve their proteolytic stability, methods such as integrating non-canonical amino acids (ncAAs) into their peptide sequence have been adopted, which also improves their potency and spectrum of action. The benefits of ncAA incorporation have been made possible by solid-phase peptide synthesis. However, this method is not always suitable for commercial production of AMPs because of poor yield, scale-up difficulties, and its non-'green' nature. Bioincorporation of ncAA as a method of integration is an emerging field geared towards tackling the challenges of solid-phase synthesis as a green, cheaper, and scalable alternative for commercialisation of AMPs. This review focusses on the bioincorporation of ncAAs; some challenges associated with the methods are outlined, and notes are given on how to overcome these challenges. The review focusses particularly on addressing two key challenges: AMP cytotoxicity towards microbial cell factories and the uptake of ncAAs that are unfavourable to them. Overcoming these challenges will draw us closer to a greater yield and an environmentally friendly and sustainable approach to make AMPs more druggable.
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Affiliation(s)
| | - Rajesh Kuppusamy
- University of New South Wales, Kensington, New South Wales, Australia
| | | | - Naresh Kumar
- University of New South Wales, Kensington, New South Wales, Australia
| | - Mark D P Willcox
- University of New South Wales, Kensington, New South Wales, Australia
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5
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Free TJ, Talley JP, Hyer CD, Miller CJ, Griffitts JS, Bundy BC. Engineering the Signal Resolution of a Paper-Based Cell-Free Glutamine Biosensor with Genetic Engineering, Metabolic Engineering, and Process Optimization. SENSORS (BASEL, SWITZERLAND) 2024; 24:3073. [PMID: 38793927 PMCID: PMC11124800 DOI: 10.3390/s24103073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 05/03/2024] [Accepted: 05/10/2024] [Indexed: 05/26/2024]
Abstract
Specialized cancer treatments have the potential to exploit glutamine dependence to increase patient survival rates. Glutamine diagnostics capable of tracking a patient's response to treatment would enable a personalized treatment dosage to optimize the tradeoff between treatment success and dangerous side effects. Current clinical glutamine testing requires sophisticated and expensive lab-based tests, which are not broadly available on a frequent, individualized basis. To address the need for a low-cost, portable glutamine diagnostic, this work engineers a cell-free glutamine biosensor to overcome assay background and signal-to-noise limitations evident in previously reported studies. The findings from this work culminate in the development of a shelf-stable, paper-based, colorimetric glutamine test with a high signal strength and a high signal-to-background ratio for dramatically improved signal resolution. While the engineered glutamine test is important progress towards improving the management of cancer and other health conditions, this work also expands the assay development field of the promising cell-free biosensing platform, which can facilitate the low-cost detection of a broad variety of target molecules with high clinical value.
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Affiliation(s)
- Tyler J. Free
- Department of Chemical Engineering, Brigham Young University, Provo, UT 84602, USA
| | - Joseph P. Talley
- Department of Chemical Engineering, Brigham Young University, Provo, UT 84602, USA
| | - Chad D. Hyer
- Department of Chemical Engineering, Brigham Young University, Provo, UT 84602, USA
| | - Catherine J. Miller
- Department of Chemical Engineering, Brigham Young University, Provo, UT 84602, USA
| | - Joel S. Griffitts
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT 84602, USA
| | - Bradley C. Bundy
- Department of Chemical Engineering, Brigham Young University, Provo, UT 84602, USA
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6
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Lee MS, Lee JA, Biondo JR, Lux JE, Raig RM, Berger PN, Bernhards CB, Kuhn DL, Gupta MK, Lux MW. Cell-Free Protein Expression in Polymer Materials. ACS Synth Biol 2024; 13:1152-1164. [PMID: 38467017 PMCID: PMC11036507 DOI: 10.1021/acssynbio.3c00628] [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: 10/12/2023] [Revised: 01/26/2024] [Accepted: 02/22/2024] [Indexed: 03/13/2024]
Abstract
While synthetic biology has advanced complex capabilities such as sensing and molecular synthesis in aqueous solutions, important applications may also be pursued for biological systems in solid materials. Harsh processing conditions used to produce many synthetic materials such as plastics make the incorporation of biological functionality challenging. One technology that shows promise in circumventing these issues is cell-free protein synthesis (CFPS), where core cellular functionality is reconstituted outside the cell. CFPS enables genetic functions to be implemented without the complications of membrane transport or concerns over the cellular viability or release of genetically modified organisms. Here, we demonstrate that dried CFPS reactions have remarkable tolerance to heat and organic solvent exposure during the casting processes for polymer materials. We demonstrate the utility of this observation by creating plastics that have spatially patterned genetic functionality, produce antimicrobials in situ, and perform sensing reactions. The resulting materials unlock the potential to deliver DNA-programmable biofunctionality in a ubiquitous class of synthetic materials.
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Affiliation(s)
- Marilyn S. Lee
- U.S.
Army Combat Capabilities Development Command Chemical Biological Center, 5183 Blackhawk Road, Aberdeen Proving Ground, Maryland 21010, United States
| | - Jennifer A. Lee
- U.S.
Army Combat Capabilities Development Command Chemical Biological Center, 5183 Blackhawk Road, Aberdeen Proving Ground, Maryland 21010, United States
- Defense
Threat Reduction Agency, 2800 Bush River Road, Gunpowder, Maryland 21010, United States
| | - John R. Biondo
- U.S.
Army Combat Capabilities Development Command Chemical Biological Center, 5183 Blackhawk Road, Aberdeen Proving Ground, Maryland 21010, United States
- Excet
Inc., 6225 Brandon Avenue,
Suite 360, Springfield, Virginia 22150, United States
| | - Jeffrey E. Lux
- US
Air Force Research Laboratory, 2179 12th Street, B652/R122, Wright-Patterson Air Force Base, Ohio 45433, United States
- UES
Inc., 4401 Dayton-Xenia
Road, Dayton, Ohio 45432, United States
| | - Rebecca M. Raig
- US
Air Force Research Laboratory, 2179 12th Street, B652/R122, Wright-Patterson Air Force Base, Ohio 45433, United States
- UES
Inc., 4401 Dayton-Xenia
Road, Dayton, Ohio 45432, United States
| | - Pierce N. Berger
- U.S.
Army Combat Capabilities Development Command Chemical Biological Center, 5183 Blackhawk Road, Aberdeen Proving Ground, Maryland 21010, United States
| | - Casey B. Bernhards
- U.S.
Army Combat Capabilities Development Command Chemical Biological Center, 5183 Blackhawk Road, Aberdeen Proving Ground, Maryland 21010, United States
| | - Danielle L. Kuhn
- U.S.
Army Combat Capabilities Development Command Chemical Biological Center, 5183 Blackhawk Road, Aberdeen Proving Ground, Maryland 21010, United States
| | - Maneesh K. Gupta
- US
Air Force Research Laboratory, 2179 12th Street, B652/R122, Wright-Patterson Air Force Base, Ohio 45433, United States
| | - Matthew W. Lux
- U.S.
Army Combat Capabilities Development Command Chemical Biological Center, 5183 Blackhawk Road, Aberdeen Proving Ground, Maryland 21010, United States
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7
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Ahsan A, Wagner D, Varaljay VA, Roman V, Kelley-Loughnane N, Reuel NF. Screening putative polyester polyurethane degrading enzymes with semi-automated cell-free expression and nitrophenyl probes. Synth Biol (Oxf) 2024; 9:ysae005. [PMID: 38414826 PMCID: PMC10898825 DOI: 10.1093/synbio/ysae005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 12/26/2023] [Accepted: 02/09/2024] [Indexed: 02/29/2024] Open
Abstract
Cell-free expression (CFE) has shown recent utility in prototyping enzymes for discovery efforts. In this work, CFE is demonstrated as an effective tool to screen putative polyester polyurethane degrading enzyme sequences sourced from metagenomic analysis of biofilms prospected on aircraft and vehicles. An automated fluid handler with a controlled temperature block is used to assemble the numerous 30 µL CFE reactions to provide more consistent results over human assembly. In sum, 13 putative hydrolase enzymes from the biofilm organisms as well as a previously verified, polyester-degrading cutinase were expressed using in-house E. coli extract and minimal linear templates. The enzymes were then tested for esterase activity directly in extract using nitrophenyl conjugated substrates, showing highest sensitivity to shorter substrates (4-nitrophenyl hexanoate and 4-nNitrophenyl valerate). This screen identified 10 enzymes with statistically significant activities against these substrates; however, all were lower in measured relative activity, on a CFE volume basis, to the established cutinase control. This approach portends the use of CFE and reporter probes to rapidly prototype, screen and design for synthetic polymer degrading enzymes from environmental consortia. Graphical Abstract.
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Affiliation(s)
- Afrin Ahsan
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, USA
| | - Dominique Wagner
- Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, OH, USA
- UES Inc., Dayton, OH, USA
| | - Vanessa A Varaljay
- Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, OH, USA
| | - Victor Roman
- Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, OH, USA
| | - Nancy Kelley-Loughnane
- Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, OH, USA
| | - Nigel F Reuel
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, USA
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8
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Hunt JP, Free TJ, Galiardi J, Watt KM, Wood DW, Bundy BC. Streamlining the Detection of Human Thyroid Receptor Ligand Interactions with XL1-Blue Cell-Free Protein Synthesis and Beta-Galactosidase Fusion Protein Biosensors. Life (Basel) 2023; 13:1972. [PMID: 37895354 PMCID: PMC10608756 DOI: 10.3390/life13101972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 09/22/2023] [Accepted: 09/25/2023] [Indexed: 10/29/2023] Open
Abstract
Thyroid receptor signaling controls major physiological processes and disrupted signaling can cause severe disorders that negatively impact human life. Consequently, methods to detect thyroid receptor ligands are of great toxicologic and pharmacologic importance. Previously, we reported thyroid receptor ligand detection with cell-free protein synthesis of a chimeric fusion protein composed of the human thyroid receptor beta (hTRβ) receptor activator and a β-lactamase reporter. Here, we report a 60% reduction in sensing cost by reengineering the chimeric fusion protein biosensor to include a reporter system composed of either the full-length beta galactosidase (β-gal), the alpha fragment of β-gal (β-gal-α), or a split alpha fragment of the β-gal (split β-gal-α). These biosensor constructs are deployed using E. coli XL1-Blue cell extract to (1) avoid the β-gal background activity abundant in BL21 cell extract and (2) facilitate β-gal complementation reporter activity to detect human thyroid receptor ligands. These results constitute a promising platform for high throughput screening and potentially the portable detection of human thyroid receptor ligands.
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Affiliation(s)
- J. Porter Hunt
- Department of Chemical Engineering, Brigham Young University, Provo, UT 84602, USA
| | - Tyler J. Free
- Department of Chemical Engineering, Brigham Young University, Provo, UT 84602, USA
| | - Jackelyn Galiardi
- Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - Kevin M. Watt
- Department of Pediatrics, University of Utah, Salt Lake City, UT 84108, USA
| | - David W. Wood
- Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - Bradley C. Bundy
- Department of Chemical Engineering, Brigham Young University, Provo, UT 84602, USA
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9
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Liu J, Hu Y, Gu W, Lan H, Zhang Z, Jiang L, Xu X. Research progress on the application of cell-free synthesis systems for enzymatic processes. Crit Rev Biotechnol 2023; 43:938-955. [PMID: 35994247 DOI: 10.1080/07388551.2022.2090314] [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] [Received: 10/13/2021] [Revised: 02/24/2022] [Accepted: 04/09/2022] [Indexed: 11/03/2022]
Abstract
Cell-free synthesis systems can complete the transcription and translation process in vitro to produce complex proteins that are difficult to be expressed in traditional cell-based systems. Such systems also can be used for the assembly of efficient localized multienzyme cascades to synthesize products that are toxic to cells. Cell-free synthesis systems provide a simpler and faster engineering solution than living cells, allowing unprecedented design freedom. This paper reviews the latest progress on the application of cell-free synthesis systems in the field of enzymatic catalysis, including cell-free protein synthesis and cell-free metabolic engineering. In cell-free protein synthesis: complex proteins, toxic proteins, membrane proteins, and artificial proteins containing non-natural amino acids can be easily synthesized by directly controlling the reaction conditions in the cell-free system. In cell-free metabolic engineering, the synthesis of desired products can be made more specific and efficient by designing metabolic pathways and screening biocatalysts based on purified enzymes or crude extracts. Through the combination of cell-free synthesis systems and emerging technologies, such as: synthetic biology, microfluidic control, cofactor regeneration, and artificial scaffolds, we will be able to build increasingly complex biomolecule systems. In the next few years, these technologies are expected to mature and reach industrialization, providing innovative platforms for a wide range of biotechnological applications.
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Affiliation(s)
- Jie Liu
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Yongqi Hu
- School of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Wanyi Gu
- School of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Haiquan Lan
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Zhidong Zhang
- Institute of Microbiology, Xinjiang Academy of Agricultural Sciences, Urumqi, China
| | - Ling Jiang
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, China
| | - Xian Xu
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
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10
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Willett E, Banta S. Synthetic NAD(P)(H) Cycle for ATP Regeneration. ACS Synth Biol 2023. [PMID: 37369039 DOI: 10.1021/acssynbio.3c00172] [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: 06/29/2023]
Abstract
ATP is the energy currency of the cell and new methods for ATP regeneration will benefit a range of emerging biotechnology applications including synthetic cells. We designed and assembled a membraneless ATP-regenerating enzymatic cascade by exploiting the substrate specificities of selected NAD(P)(H)-dependent oxidoreductases combined with substrate-specific kinases. The enzymes in the NAD(P)(H) cycle were selected to avoid cross-reactions, and the cascade was driven by irreversible fuel oxidation. As a proof-of-concept, formate oxidation was chosen as the fueling reaction. ATP regeneration was accomplished via the phosphorylation of NADH to NADPH and the subsequent transfer of the phosphate to ADP by a reversible NAD+ kinase. The cascade was able to regenerate ATP at a high rate (up to 0.74 mmol/L/h) for hours, and >90% conversion of ADP to ATP using monophosphate was also demonstrated. The cascade was used to regenerate ATP for use in cell free protein synthesis reactions, and the ATP production rate was further enhanced when powered by the multistep oxidation of methanol. The NAD(P)(H) cycle provides a simple cascade for the in vitro regeneration of ATP without the need for a pH-gradient or costly phosphate donors.
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Affiliation(s)
- Emma Willett
- Department of Chemical Engineering, Columbia University, New York, New York 10027, United States
| | - Scott Banta
- Department of Chemical Engineering, Columbia University, New York, New York 10027, United States
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11
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Wagner L, Jules M, Borkowski O. What remains from living cells in bacterial lysate-based cell-free systems. Comput Struct Biotechnol J 2023; 21:3173-3182. [PMID: 37333859 PMCID: PMC10275740 DOI: 10.1016/j.csbj.2023.05.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 05/23/2023] [Accepted: 05/23/2023] [Indexed: 06/20/2023] Open
Abstract
Because they mimic cells while offering an accessible and controllable environment, lysate-based cell-free systems (CFS) have emerged as valuable biotechnology tools for synthetic biology. Historically used to uncover fundamental mechanisms of life, CFS are nowadays used for a multitude of purposes, including protein production and prototyping of synthetic circuits. Despite the conservation of fundamental functions in CFS like transcription and translation, RNAs and certain membrane-embedded or membrane-bound proteins of the host cell are lost when preparing the lysate. As a result, CFS largely lack some essential properties of living cells, such as the ability to adapt to changing conditions, to maintain homeostasis and spatial organization. Regardless of the application, shedding light on the black-box of the bacterial lysate is necessary to fully exploit the potential of CFS. Most measurements of the activity of synthetic circuits in CFS and in vivo show significant correlations because these only require processes that are preserved in CFS, like transcription and translation. However, prototyping circuits of higher complexity that require functions that are lost in CFS (cell adaptation, homeostasis, spatial organization) will not show such a good correlation with in vivo conditions. Both for prototyping circuits of higher complexity and for building artificial cells, the cell-free community has developed devices to reconstruct cellular functions. This mini-review compares bacterial CFS to living cells, focusing on functional and cellular process differences and the latest developments in restoring lost functions through complementation of the lysate or device engineering.
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12
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Dinglasan JLN, Sword TT, Barker JW, Doktycz MJ, Bailey CB. Investigating and Optimizing the Lysate-Based Expression of Nonribosomal Peptide Synthetases Using a Reporter System. ACS Synth Biol 2023; 12:1447-1460. [PMID: 37039644 PMCID: PMC11236431 DOI: 10.1021/acssynbio.2c00658] [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] [Indexed: 04/12/2023]
Abstract
Lysate-based cell-free expression (CFE) systems are accessible platforms for expressing proteins that are difficult to synthesize in vivo, such as nonribosomal peptide synthetases (NRPSs). NRPSs are large (>100 kDa), modular enzyme complexes that synthesize bioactive peptide natural products. This synthetic process is analogous to transcription/translation (TX/TL) in lysates, resulting in potential resource competition between NRPS expression and NRPS activity in cell-free environments. Moreover, CFE conditions depend on the size and structure of the protein. Here, a reporter system for rapidly investigating and optimizing reaction environments for NRPS CFE is described. This strategy is demonstrated in E. coli lysate reactions using blue pigment synthetase A (BpsA), a model NRPS, carrying a C-terminal tetracysteine (TC) tag which forms a fluorescent complex with the biarsenical dye, FlAsH. A colorimetric assay was adapted for lysate reactions to detect the blue pigment product, indigoidine, of cell-free expressed BpsA-TC, confirming that the tagged enzyme is catalytically active. An optimized protocol for end point TC/FlAsH complex measurements in reactions enables quick comparisons of full-length BpsA-TC expressed under different reaction conditions, defining unique requirements for NRPS expression that are related to the protein's catalytic activity and size. Importantly, these protein-dependent CFE conditions enable higher indigoidine titer and improve the expression of other monomodular NRPSs. Notably, these conditions differ from those used for the expression of superfolder GFP (sfGFP), a common reporter for optimizing lysate-based CFE systems, indicating the necessity for tailored reporters to optimize expression for specific enzyme classes. The reporter system is anticipated to advance lysate-based CFE systems for complex enzyme synthesis, enabling natural product discovery.
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Affiliation(s)
- Jaime Lorenzo N Dinglasan
- Graduate School of Genome Science & Technology, University of Tennessee-Knoxville, Knoxville, Tennessee 37996, United States
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Tien T Sword
- Department of Chemistry, University of Tennessee-Knoxville, Knoxville, Tennessee 37996, United States
| | - J William Barker
- Department of Chemistry, University of Tennessee-Knoxville, Knoxville, Tennessee 37996, United States
| | - Mitchel J Doktycz
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Constance B Bailey
- Department of Chemistry, University of Tennessee-Knoxville, Knoxville, Tennessee 37996, United States
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13
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Cell-free protein synthesis system for bioanalysis: Advances in methods and applications. Trends Analyt Chem 2023. [DOI: 10.1016/j.trac.2023.117015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
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14
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Rasor BJ, Chirania P, Rybnicky GA, Giannone RJ, Engle NL, Tschaplinski TJ, Karim AS, Hettich RL, Jewett MC. Mechanistic Insights into Cell-Free Gene Expression through an Integrated -Omics Analysis of Extract Processing Methods. ACS Synth Biol 2023; 12:405-418. [PMID: 36700560 DOI: 10.1021/acssynbio.2c00339] [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: 01/27/2023]
Abstract
Cell-free systems derived from crude cell extracts have developed into tools for gene expression, with applications in prototyping, biosensing, and protein production. Key to the development of these systems is optimization of cell extract preparation methods. However, the applied nature of these optimizations often limits investigation into the complex nature of the extracts themselves, which contain thousands of proteins and reaction networks with hundreds of metabolites. Here, we sought to uncover the black box of proteins and metabolites in Escherichia coli cell-free reactions based on different extract preparation methods. We assess changes in transcription and translation activity from σ70 promoters in extracts prepared with acetate or glutamate buffer and the common post-lysis processing steps of a runoff incubation and dialysis. We then utilize proteomic and metabolomic analyses to uncover potential mechanisms behind these changes in gene expression, highlighting the impact of cold shock-like proteins and the role of buffer composition.
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Affiliation(s)
- Blake J Rasor
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, United States.,Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208, United States.,Center for Synthetic Biology, Northwestern University, Evanston, Illinois 60208, United States
| | - Payal Chirania
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.,Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Grant A Rybnicky
- Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208, United States.,Center for Synthetic Biology, Northwestern University, Evanston, Illinois 60208, United States.,Interdisciplinary Biological Sciences Graduate Program, Northwestern University, Evanston, Illinois 60208, United States
| | - Richard J Giannone
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Nancy L Engle
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Timothy J Tschaplinski
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Ashty S Karim
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, United States.,Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208, United States.,Center for Synthetic Biology, Northwestern University, Evanston, Illinois 60208, United States
| | - Robert L Hettich
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Michael C Jewett
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, United States.,Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208, United States.,Center for Synthetic Biology, Northwestern University, Evanston, Illinois 60208, United States.,Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, Illinois 60611, United States.,Simpson Querrey Institute, Northwestern University, Chicago, Illinois 60611, United States
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15
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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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16
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Cui Y, Chen X, Wang Z, Lu Y. Cell-Free PURE System: Evolution and Achievements. BIODESIGN RESEARCH 2022; 2022:9847014. [PMID: 37850137 PMCID: PMC10521753 DOI: 10.34133/2022/9847014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Accepted: 08/16/2022] [Indexed: 10/19/2023] Open
Abstract
The cell-free protein synthesis (CFPS) system, as a technical core of synthetic biology, can simulate the transcription and translation process in an in vitro open environment without a complete living cell. It has been widely used in basic and applied research fields because of its advanced engineering features in flexibility and controllability. Compared to a typical crude extract-based CFPS system, due to defined and customizable components and lacking protein-degrading enzymes, the protein synthesis using recombinant elements (PURE) system draws great attention. This review first discusses the elemental composition of the PURE system. Then, the design and preparation of functional proteins for the PURE system, especially the critical ribosome, were examined. Furthermore, we trace the evolving development of the PURE system in versatile areas, including prototyping, synthesis of unnatural proteins, peptides and complex proteins, and biosensors. Finally, as a state-of-the-art engineering strategy, this review analyzes the opportunities and challenges faced by the PURE system in future scientific research and diverse applications.
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Affiliation(s)
- Yi Cui
- Key Laboratory of Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
- College of Life Sciences, Shenyang Normal University, Shenyang 110034, Liaoning, China
| | - Xinjie Chen
- Key Laboratory of Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Ze Wang
- College of Life Sciences, Shenyang Normal University, Shenyang 110034, Liaoning, China
| | - Yuan Lu
- Key Laboratory of Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
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17
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Rhea KA, McDonald ND, Cole SD, Noireaux V, Lux MW, Buckley PE. Variability in cell-free expression reactions can impact qualitative genetic circuit characterization. Synth Biol (Oxf) 2022; 7:ysac011. [PMID: 35966404 PMCID: PMC9365049 DOI: 10.1093/synbio/ysac011] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 06/24/2022] [Accepted: 08/01/2022] [Indexed: 09/21/2023] Open
Abstract
Cell-free expression systems provide a suite of tools that are used in applications from sensing to biomanufacturing. One of these applications is genetic circuit prototyping, where the lack of cloning is required and a high degree of control over reaction components and conditions enables rapid testing of design candidates. Many studies have shown utility in the approach for characterizing genetic regulation elements, simple genetic circuit motifs, protein variants or metabolic pathways. However, variability in cell-free expression systems is a known challenge, whether between individuals, laboratories, instruments, or batches of materials. While the issue of variability has begun to be quantified and explored, little effort has been put into understanding the implications of this variability. For genetic circuit prototyping, it is unclear when and how significantly variability in reaction activity will impact qualitative assessments of genetic components, e.g. relative activity between promoters. Here, we explore this question by assessing DNA titrations of seven genetic circuits of increasing complexity using reaction conditions that ostensibly follow the same protocol but vary by person, instrument and material batch. Although the raw activities vary widely between the conditions, by normalizing within each circuit across conditions, reasonably consistent qualitative performance emerges for the simpler circuits. For the most complex case involving expression of three proteins, we observe a departure from this qualitative consistency, offering a provisional cautionary line where normal variability may disrupt reliable reuse of prototyping results. Our results also suggest that a previously described closed loop controller circuit may help to mitigate such variability, encouraging further work to design systems that are robust to variability. Graphical Abstract.
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Affiliation(s)
- Katherine A Rhea
- US Army Combat Capabilities Development Command Chemical Biological Center, Aberdeen Proving Ground, MD, USA
| | - Nathan D McDonald
- US Army Combat Capabilities Development Command Chemical Biological Center, Aberdeen Proving Ground, MD, USA
| | - Stephanie D Cole
- US Army Combat Capabilities Development Command Chemical Biological Center, Aberdeen Proving Ground, MD, USA
| | - Vincent Noireaux
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, USA
| | - Matthew W Lux
- US Army Combat Capabilities Development Command Chemical Biological Center, Aberdeen Proving Ground, MD, USA
| | - Patricia E Buckley
- US Army Combat Capabilities Development Command Chemical Biological Center, Aberdeen Proving Ground, MD, USA
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18
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Yang C, Yang M, Zhao W, Ding Y, Wang Y, Li J. Establishing a Klebsiella pneumoniae-Based Cell-Free Protein Synthesis System. Molecules 2022; 27:molecules27154684. [PMID: 35897861 PMCID: PMC9330377 DOI: 10.3390/molecules27154684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 06/25/2022] [Accepted: 07/18/2022] [Indexed: 02/01/2023] Open
Abstract
Cell-free protein synthesis (CFPS) systems are emerging as powerful platforms for in vitro protein production, which leads to the development of new CFPS systems for different applications. To expand the current CFPS toolkit, here we develop a novel CFPS system derived from a chassis microorganism Klebsiella pneumoniae, an important industrial host for heterologous protein expression and the production of many useful chemicals. First, we engineered the K. pneumoniae strain by deleting a capsule formation-associated wzy gene. This capsule-deficient strain enabled easy collection of the cell biomass for preparing cell extracts. Then, we optimized the procedure of cell extract preparation and the reaction conditions for CFPS. Finally, the optimized CFPS system was able to synthesize a reporter protein (superfolder green fluorescent protein, sfGFP) with a maximum yield of 253 ± 15.79 μg/mL. Looking forward, our K. pneumoniae-based CFPS system will not only expand the toolkit for protein synthesis, but also provide a new platform for constructing in vitro metabolic pathways for the synthesis of high-value chemicals.
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Affiliation(s)
- Chen Yang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China;
| | - Miaomiao Yang
- Clinical Pathology Center, The Fourth Affiliated Hospital of Anhui Medical University, Hefei 230012, China;
- Department of Biological Physics, University of Science and Technology of China, Hefei 230026, China
| | - Wanhua Zhao
- College of Life Sciences, Jiangxi Agricultural University, Nanchang 330045, China; (W.Z.); (Y.D.)
| | - Yue Ding
- College of Life Sciences, Jiangxi Agricultural University, Nanchang 330045, China; (W.Z.); (Y.D.)
| | - Yu Wang
- College of Life Sciences, Jiangxi Agricultural University, Nanchang 330045, China; (W.Z.); (Y.D.)
- Correspondence: (Y.W.); (J.L.)
| | - Jian Li
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China;
- Correspondence: (Y.W.); (J.L.)
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19
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Copeland CE, Kim J, Copeland PL, Heitmeier CJ, Kwon YC. Characterizing a New Fluorescent Protein for a Low Limit of Detection Sensing in the Cell-Free System. ACS Synth Biol 2022; 11:2800-2810. [PMID: 35850511 PMCID: PMC9396652 DOI: 10.1021/acssynbio.2c00180] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cell-free protein synthesis-based biosensors have been developed as highly accurate, low-cost biosensors. However, since most biomarkers exist at low concentrations in various types of biopsies, the biosensor's dynamic range must be increased in the system to achieve low limits of detection necessary while deciphering from higher background signals. Many attempts to increase the dynamic range have relied on amplifying the input signal from the analyte, which can lead to complications of false positives. In this study, we aimed to increase the protein synthesis capability of the cell-free protein synthesis system and the output signal of the reporter protein to achieve a lower limit of detection. We utilized a new fluorescent protein, mNeonGreen, which produces a higher output than those commonly used in cell-free biosensors. Optimizations of DNA sequence and the subsequent cell-free protein synthesis reaction conditions allowed characterizing protein expression variability by given DNA template types, reaction environment, and storage additives that cause the greatest time constraint on designing the cell-free biosensor. Finally, we characterized the fluorescence kinetics of mNeonGreen compared to the commonly used reporter protein, superfolder green fluorescent protein. We expect that this finely tuned cell-free protein synthesis platform with the new reporter protein can be used with sophisticated synthetic gene circuitry networks to increase the dynamic range of a cell-free biosensor to reach lower detection limits and reduce the false-positive proportion.
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Affiliation(s)
- Caroline E Copeland
- Department of Biological and Agricultural Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Jeehye Kim
- Department of Biological and Agricultural Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Pearce L Copeland
- Department of Biological and Agricultural Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Chloe J Heitmeier
- Department of Biological and Agricultural Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Yong-Chan Kwon
- Department of Biological and Agricultural Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States.,Louisiana State University Agricultural Center, Baton Rouge, Louisiana 70803, United States
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20
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Jew K, Smith PEJ, So B, Kasman J, Oza JP, Black MW. Characterizing and Improving pET Vectors for Cell-free Expression. Front Bioeng Biotechnol 2022; 10:895069. [PMID: 35814024 PMCID: PMC9259831 DOI: 10.3389/fbioe.2022.895069] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Accepted: 05/26/2022] [Indexed: 11/15/2022] Open
Abstract
Cell-free protein synthesis (CFPS) is an in vitro process that enables diverse applications in research, biomanufacturing, point-of-care diagnostics, therapeutics, and education using minimal laboratory equipment and reagents. One of the major limitations of CFPS implementation is its sensitivity to plasmid type. Specifically, plasmid templates based on commonly used vector backbones such as the pET series of bacterial expression vectors result in the inferior production of proteins. To overcome this limitation, we have evaluated the effect of expression cassette elements present in the pET30 vector on protein production across three different CFPS systems: NEBExpress, PURExpress, and CFAI-based E. coli extracts. Through the systematic elimination of genetic elements within the pET30 vector, we have identified elements that are responsible for the poor performance of pET30 vectors in the various CFPS systems. As a result, we demonstrate that through the removal of the lac operator (lacO) and N-terminal tags included in the vector backbone sequence, a pET vector can support high titers of protein expression when using extract-based CFPS systems. This work provides two key advances for the research community: 1) identification of vector sequence elements that affect robust production of proteins; 2) evaluation of expression across three unique CFPS systems including CFAI extracts, NEBexpress, and PURExpress. We anticipate that this work will improve access to CFPS by enabling researchers to choose the correct expression backbone within the context of their preferred expression system.
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Affiliation(s)
- Kara Jew
- Biological Sciences Department, California Polytechnic State University, San Luis Obispo, CA, United States
| | - Philip E. J. Smith
- Chemistry & Biochemistry Department, California Polytechnic State University, San Luis Obispo, CA, United States
| | - Byungcheol So
- Chemistry & Biochemistry Department, California Polytechnic State University, San Luis Obispo, CA, United States
| | - Jillian Kasman
- Chemistry & Biochemistry Department, California Polytechnic State University, San Luis Obispo, CA, United States
| | - Javin P. Oza
- Chemistry & Biochemistry Department, California Polytechnic State University, San Luis Obispo, CA, United States
| | - Michael W. Black
- Biological Sciences Department, California Polytechnic State University, San Luis Obispo, CA, United States
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21
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Mullin AC, Slouka T, Oza JP. Simple Extract Preparation Methods for E. coli-Based Cell-Free Expression. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2022; 2433:51-64. [PMID: 34985736 DOI: 10.1007/978-1-0716-1998-8_2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Cell-free protein synthesis (CFPS) is a powerful platform for synthetic biology, allowing for the controlled expression of proteins without reliance on living cells. However, the process of producing the cell extract, a key component of cell-free reactions, can be a bottleneck for new users to adopt CFPS as it requires technical knowledge and significant researcher oversight. Here, we provide a detailed method for implementing a simplified cell extract preparation workflow using CFAI media. We also provide a detailed protocol for the alternative, 2x YPTG media-based preparation process, as it represents a useful benchmark within the cell-free community.
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Affiliation(s)
- Alissa C Mullin
- Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, CA, USA
| | - Taylor Slouka
- Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, CA, USA
| | - Javin P Oza
- Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, CA, USA.
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22
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Carr AR, Dopp JL, Wu K, Sadat Mousavi P, Jo YR, McNeley CE, Lynch ZT, Pardee K, Green AA, Reuel NF. Toward Mail-in-Sensors for SARS-CoV-2 Detection: Interfacing Gel Switch Resonators with Cell-Free Toehold Switches. ACS Sens 2022; 7:806-815. [PMID: 35254055 DOI: 10.1021/acssensors.1c02450] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The COVID-19 pandemic has emphasized the importance of widespread testing to control the spread of infectious diseases. The rapid development, scale-up, and deployment of viral and antibody detection methods since the beginning of the pandemic have greatly increased testing capacity. Desirable attributes of detection methods are low product costs, self-administered protocols, and the ability to be mailed in sealed envelopes for the safe analysis and subsequent logging to public health databases. Herein, such a platform is demonstrated with a screen-printed, inductor-capacitor (LC) resonator as a transducer and a toehold switch coupled with cell-free expression as the biological selective recognition element. In the presence of the N-gene from SARS-CoV-2, the toehold switch relaxes, protease enzyme is expressed, and it degrades a gelatin switch that ultimately shifts the resonant frequency of the planar resonant sensor. The gelatin switch resonator (GSR) can be analyzed through a sealed envelope allowing for assessment without the need for careful sample handling with personal protective equipment or the need for workup with other reagents. The toehold switch used in this sensor demonstrated selectivity to SARS-CoV-2 virus over three seasonal coronaviruses and SARS-CoV-1, with a limit of detection of 100 copies/μL. The functionality of the platform and assessment in a sealed envelope with an automated scanner is shown with overnight shipment, and further improvements are discussed to increase signal stability and further simplify user protocols toward a mail-in platform.
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Affiliation(s)
- Adam R. Carr
- Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011, United States
| | - Jared L. Dopp
- Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011, United States
| | - Kaiyue Wu
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, United States
| | | | - Yeong Ran Jo
- Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011, United States
| | - Ciara E. McNeley
- Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011, United States
| | - Zachary T. Lynch
- Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011, United States
| | - Keith Pardee
- University of Toronto, Leslie Dan Faculty of Pharmacy, Toronto, ON M5S 1A1, Canada
| | - Alexander A. Green
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, United States
| | - Nigel F. Reuel
- Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011, United States
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23
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Thakur M, Breger JC, Susumu K, Oh E, Spangler JR, Medintz IL, Walper SA, Ellis GA. Self-assembled nanoparticle-enzyme aggregates enhance functional protein production in pure transcription-translation systems. PLoS One 2022; 17:e0265274. [PMID: 35298538 PMCID: PMC8929567 DOI: 10.1371/journal.pone.0265274] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 02/27/2022] [Indexed: 11/19/2022] Open
Abstract
Cell-free protein synthesis systems (CFPS) utilize cellular transcription and translation (TX-TL) machinery to synthesize proteins in vitro. These systems are useful for multiple applications including production of difficult proteins, as high-throughput tools for genetic circuit screening, and as systems for biosensor development. Though rapidly evolving, CFPS suffer from some disadvantages such as limited reaction rates due to longer diffusion times, significant cost per assay when using commercially sourced materials, and reduced reagent stability over prolonged periods. To address some of these challenges, we conducted a series of proof-of-concept experiments to demonstrate enhancement of CFPS productivity via nanoparticle assembly driven nanoaggregation of its constituent proteins. We combined a commercially available CFPS that utilizes purified polyhistidine-tagged (His-tag) TX-TL machinery with CdSe/CdS/ZnS core/shell/shell quantum dots (QDs) known to readily coordinate His-tagged proteins in an oriented fashion. We show that nanoparticle scaffolding of the CFPS cross-links the QDs into nanoaggregate structures while enhancing the production of functional recombinant super-folder green fluorescent protein and phosphotriesterase, an organophosphate hydrolase; the latter by up to 12-fold. This enhancement, which occurs by an undetermined mechanism, has the potential to improve CFPS in general and specifically CFPS-based biosensors (faster response time) while also enabling rapid detoxification/bioremediation through point-of-concern synthesis of similar catalytic enzymes. We further show that such nanoaggregates improve production in diluted CFPS reactions, which can help to save money and extend the amount of these costly reagents. The results are discussed in the context of what may contribute mechanistically to the enhancement and how this can be applied to other CFPS application scenarios.
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Affiliation(s)
- Meghna Thakur
- Center for Bio/Molecular Science and Engineering, Code 6900, U.S. Naval Research Laboratory, Washington, District of Columbia, United States of America
- College of Science, George Mason University, Fairfax, Virginia, United States of America
| | - Joyce C. Breger
- Center for Bio/Molecular Science and Engineering, Code 6900, U.S. Naval Research Laboratory, Washington, District of Columbia, United States of America
| | - Kimihiro Susumu
- Optical Sciences Division, Code 5600, U.S. Naval Research Laboratory, Washington, District of Columbia, United States of America
- Jacobs Corporation, Dallas, Texas, United States of America
| | - Eunkeu Oh
- Optical Sciences Division, Code 5600, U.S. Naval Research Laboratory, Washington, District of Columbia, United States of America
| | - Joseph R. Spangler
- Center for Bio/Molecular Science and Engineering, Code 6900, U.S. Naval Research Laboratory, Washington, District of Columbia, United States of America
| | - Igor L. Medintz
- Center for Bio/Molecular Science and Engineering, Code 6900, U.S. Naval Research Laboratory, Washington, District of Columbia, United States of America
| | - Scott A. Walper
- Center for Bio/Molecular Science and Engineering, Code 6900, U.S. Naval Research Laboratory, Washington, District of Columbia, United States of America
| | - Gregory A. Ellis
- Center for Bio/Molecular Science and Engineering, Code 6900, U.S. Naval Research Laboratory, Washington, District of Columbia, United States of America
- * E-mail:
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24
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A De Novo Optimized Cell-Free System for the Expression of Soluble and Active Human Tumor Necrosis Factor-Alpha. BIOLOGY 2022; 11:biology11020157. [PMID: 35205024 PMCID: PMC8868817 DOI: 10.3390/biology11020157] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 01/14/2022] [Accepted: 01/17/2022] [Indexed: 11/27/2022]
Abstract
Simple Summary As a result of increasing demand for the pleiotropic cytokine TNF-α, recombinant human TNF-α protein with appropriate bioactivities was produced in several heterologous in vivo expression systems. While in vivo expression of this cytokine is laborious and lengthy, cell-free or in vitro expression system has the benefits of speed, simplicity, flexibility, focus of all the system energy on target protein synthesis alone, besides high soluble and functional protein yield. Therefore, we employed and optimized an E. coli-based cell-free system for the first time to express recombinant human TNF-α. Our findings revealed that cell-free expression system can be an alternative platform for producing soluble and functionally active recombinant TNF-α with a yield of 390 µg/mL in only 2 h at a temperature of 40 °C for further research and clinical trials. Abstract Cell-free (in vitro) expression is a robust alternative platform to the cell-based (in vivo) system for recombinant protein production. Tumor necrosis factor-alpha (TNF-α) is an effective pro-inflammatory cytokine with pleiotropic effects. The aim of the current study was de novo optimized expression of soluble and active human TNF-α by an in vitro method in an E. coli-based cell-free protein synthesis (CFPS) system and its biological activity evaluation. The codon-optimized synthetic human TNF-α gene was constructed by a two-step PCR, cloned into pET101/D-TOPO vector and then expressed by the E. coli CFPS system. Cell-free expression of the soluble protein was optimized using a response surface methodology (RSM). The anticancer activity of purified human TNF-α was assessed against three human cancer cell lines: Caco-2, HepG-2 and MCF-7. Data from RSM revealed that the lowest value (7.2 µg/mL) of cell-free production of recombinant human TNF-α (rhTNF-α) was obtained at a certain incubation time (6 h) and incubation temperature (20 °C), while the highest value (350 µg/mL) was recorded at 4 h and 35 °C. This rhTNF-α showed a significant anticancer potency. Our findings suggest a cell-free expression system as an alternative platform for producing soluble and functionally active recombinant TNF-α for further research and clinical trials.
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25
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Hiering F, Failmezger J, Siemann-Herzberg M. Preparation and Screening of Cell-Free Extract from Nongrowing Escherichia coli A19 Cells. Methods Mol Biol 2022; 2433:65-73. [PMID: 34985737 DOI: 10.1007/978-1-0716-1998-8_3] [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: 06/14/2023]
Abstract
Cell-free extracts have been researched and continuously streamlined for around 50 years. It is believed that these extracts work best when routinely obtained from exponentially growing cells to capture the most active translation system. Here we report on an active cell-free extract derived from E. coli A19 that was harvested under nongrowing, stressed conditions. Although this process is based on the conventional routine process for the production of S30-extracts, our process is less labor intensive and reduces variability between extracts.
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Affiliation(s)
- Florian Hiering
- Institute of Biochemical Engineering, Universität Stuttgart, Stuttgart, Germany
| | - Jurek Failmezger
- Institute of Biochemical Engineering, Universität Stuttgart, Stuttgart, Germany
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26
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Meyer C, Zhou C, Fang Z, Longo ML, Pan T, Tan C. High-Throughput Experimentation Using Cell-Free Protein Synthesis Systems. Methods Mol Biol 2022; 2433:121-134. [PMID: 34985741 DOI: 10.1007/978-1-0716-1998-8_7] [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] [Indexed: 05/06/2023]
Abstract
Cell-free protein synthesis can enable the combinatorial screening of many different components and concentrations. However, manual pipetting methods are unfit to handle many cell-free reactions. Here, we describe a microfluidic method that can generate hundreds of unique submicroliter scale reactions. The method is coupled with a high yield cell-free system that can be applied for broad protein screening assays.
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Affiliation(s)
- Conary Meyer
- Department of Biomedical Engineering, University of California, Davis, CA, USA
| | - Chuqing Zhou
- Department of Biomedical Engineering, University of California, Davis, CA, USA
| | - Zecong Fang
- Department of Biomedical Engineering, University of California, Davis, CA, USA
- Institute of Biomedical and Health Engineering, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- Shenzhen Engineering Laboratory of Single-Molecule Detection and Instrument Development, Shenzhen, China
| | - Marjorie L Longo
- Department of Chemical Engineering, University of California, Davis, CA, USA
| | - Tingrui Pan
- Department of Biomedical Engineering, University of California, Davis, CA, USA
- Institute of Biomedical and Health Engineering, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- Shenzhen Engineering Laboratory of Single-Molecule Detection and Instrument Development, Shenzhen, China
- Suzhou Institute for Advanced Research, University of Science and Technology of China, Suzhou, China
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, China
| | - Cheemeng Tan
- Department of Biomedical Engineering, University of California, Davis, CA, USA.
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27
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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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28
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Burrington LR, Watts KR, Oza JP. Characterizing and Improving Reaction Times for E. coli-Based Cell-Free Protein Synthesis. ACS Synth Biol 2021; 10:1821-1829. [PMID: 34269580 DOI: 10.1021/acssynbio.1c00195] [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: 01/10/2023]
Abstract
Cell-free protein synthesis (CFPS) is a platform biotechnology that has enabled the on-demand synthesis of proteins for a variety of applications. Numerous advances have improved the productivity of the CFPS platform to result in high-yielding reactions; however, many applications remain limited due to long reaction times. To overcome this limitation, we first established the benchmarks reaction times for CFPS across in-house E. coli extracts and commercial kits. We then set out to fine-tune our in-house extract systems to improve reaction times. Through the optimization of reaction composition and titration of low-cost additives, we have identified formulations that reduce reaction times by 30-50% to obtain high protein titers for biomanufacturing applications, and reduce times by more than 50% to reach the sfGFP detection limit for applications in education and diagnostics. Under optimum conditions, we report the visible observation of sfGFP signal in less than 10 min. Altogether, these advances enhance the utility of CFPS as a rapid, user-defined platform.
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Affiliation(s)
- Logan R. Burrington
- Chemistry and Biochemistry Department, California Polytechnic State University, 1 Grand Avenue, San Luis Obispo, California 93407, United States
- Center for Applications in Biotechnology, California Polytechnic State University, 1 Grand Avenue, San Luis Obispo, California 93407, United States
| | - Katharine R. Watts
- Chemistry and Biochemistry Department, California Polytechnic State University, 1 Grand Avenue, San Luis Obispo, California 93407, United States
- Center for Applications in Biotechnology, California Polytechnic State University, 1 Grand Avenue, San Luis Obispo, California 93407, United States
| | - Javin P. Oza
- Chemistry and Biochemistry Department, California Polytechnic State University, 1 Grand Avenue, San Luis Obispo, California 93407, United States
- Center for Applications in Biotechnology, California Polytechnic State University, 1 Grand Avenue, San Luis Obispo, California 93407, United States
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29
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Pereira JM, Vieira M, Santos SM. Step-by-step design of proteins for small molecule interaction: A review on recent milestones. Protein Sci 2021; 30:1502-1520. [PMID: 33934427 PMCID: PMC8284594 DOI: 10.1002/pro.4098] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 04/21/2021] [Accepted: 04/23/2021] [Indexed: 01/01/2023]
Abstract
Protein design is the field of synthetic biology that aims at developing de novo custom-made proteins and peptides for specific applications. Despite exploring an ambitious goal, recent computational advances in both hardware and software technologies have paved the way to high-throughput screening and detailed design of novel folds and improved functionalities. Modern advances in the field of protein design for small molecule targeting are described in this review, organized in a step-by-step fashion: from the conception of a new or upgraded active binding site, to scaffold design, sequence optimization, and experimental expression of the custom protein. In each step, contemporary examples are described, and state-of-the-art software is briefly explored.
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Affiliation(s)
- José M. Pereira
- CICECO & Departamento de QuímicaUniversidade de AveiroAveiroPortugal
| | - Maria Vieira
- CICECO & Departamento de QuímicaUniversidade de AveiroAveiroPortugal
| | - Sérgio M. Santos
- CICECO & Departamento de QuímicaUniversidade de AveiroAveiroPortugal
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30
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Bouzetos E, Ganar KA, Mastrobattista E, Deshpande S, van der Oost J. (R)evolution-on-a-chip. Trends Biotechnol 2021; 40:60-76. [PMID: 34049723 DOI: 10.1016/j.tibtech.2021.04.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 04/21/2021] [Accepted: 04/23/2021] [Indexed: 01/17/2023]
Abstract
Billions of years of Darwinian evolution has led to the emergence of highly sophisticated and diverse life forms on Earth. Inspired by natural evolution, similar principles have been adopted in laboratory evolution for the fast optimization of genes and proteins for specific applications. In this review, we highlight state-of-the-art laboratory evolution strategies for protein engineering, with a special emphasis on in vitro strategies. We further describe how recent progress in microfluidic technology has allowed the generation and manipulation of artificial compartments for high-throughput laboratory evolution experiments. Expectations for the future are high: we foresee a revolution on-a-chip.
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Affiliation(s)
- Evgenios Bouzetos
- Laboratory of Microbiology, Wageningen University and Research, 6708, WE, Wageningen, The Netherlands
| | - Ketan Ashok Ganar
- Laboratory of Physical Chemistry and Soft Matter, Wageningen University and Research, 6708, WE, Wageningen, The Netherlands
| | - Enrico Mastrobattista
- Pharmaceutics Division, Utrecht Institute for Pharmaceutical Sciences (UIPS), Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Siddharth Deshpande
- Laboratory of Physical Chemistry and Soft Matter, Wageningen University and Research, 6708, WE, Wageningen, The Netherlands.
| | - John van der Oost
- Laboratory of Microbiology, Wageningen University and Research, 6708, WE, Wageningen, The Netherlands.
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31
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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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32
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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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33
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A Relationship between NTP and Cell Extract Concentration for Cell-Free Protein Expression. Life (Basel) 2021; 11:life11030237. [PMID: 33805612 PMCID: PMC7999496 DOI: 10.3390/life11030237] [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: 02/27/2021] [Revised: 03/10/2021] [Accepted: 03/11/2021] [Indexed: 01/29/2023] Open
Abstract
The cell-free protein synthesis (CFPS) that synthesizes mRNA and protein from a template DNA has been featured as an important tool to emulate living systems in vitro. However, an obstacle to emulate living cells by CFPS is the loss of activity in the case of usage of high concentration cell extracts. In this study, we found that a high concentration of NTP which inhibits in the case of lower concentration cell extract restored the loss of CFPS activity using high concentration cell extracts. The NTP restoration was independent of the energy regeneration system used, and NTP derivatives also restored the levels of CFPS using a high concentration cell extract. Experiments using dialysis mode of CFPS showed that continuous exchange of small molecule reduced levels of NTP requirement and improved reaction speed of CFPS using the high concentration of cell extract. These findings contribute to the development of a method to understand the condition of living cells by in vitro emulation, and are expected to lead to the achievement of the reconstitution of living cells from biomolecule mixtures.
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Moore SJ, Lai HE, Chee SM, Toh M, Coode S, Chengan K, Capel P, Corre C, de los Santos ELC, Freemont PS. A Streptomyces venezuelae Cell-Free Toolkit for Synthetic Biology. ACS Synth Biol 2021; 10:402-411. [PMID: 33497199 PMCID: PMC7901020 DOI: 10.1021/acssynbio.0c00581] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
![]()
Prokaryotic
cell-free coupled transcription–translation
(TX-TL) systems are emerging as a powerful tool to examine natural
product biosynthetic pathways in a test tube. The key advantages of
this approach are the reduced experimental time scales and controlled
reaction conditions. To realize this potential, it is essential to
develop specialized cell-free systems in organisms enriched for biosynthetic
gene clusters. This requires strong protein production and well-characterized
synthetic biology tools. The Streptomyces genus is
a major source of natural products. To study enzymes and pathways
from Streptomyces, we originally developed a homologous Streptomyces cell-free system to provide a native protein
folding environment, a high G+C (%) tRNA pool, and an active background
metabolism. However, our initial yields were low (36 μg/mL)
and showed a high level of batch-to-batch variation. Here, we present
an updated high-yield and robust Streptomyces TX-TL
protocol, reaching up to yields of 266 μg/mL of expressed recombinant
protein. To complement this, we rapidly characterize a range of DNA
parts with different reporters, express high G+C (%) biosynthetic
genes, and demonstrate an initial proof of concept for combined transcription,
translation, and biosynthesis of Streptomyces metabolic
pathways in a single “one-pot” reaction.
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Affiliation(s)
- Simon J. Moore
- Centre for Synthetic Biology and Innovation, Imperial College London, South Kensington Campus, Exhibition Road, London, SW7 2AZ, U.K
- Department Section of Structural and Synthetic Biology, Department of Infectious Disease; Imperial College London, South Kensington Campus, Exhibition Road, London, SW7 2AZ, U.K
- School of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, U.K
| | - Hung-En Lai
- Centre for Synthetic Biology and Innovation, Imperial College London, South Kensington Campus, Exhibition Road, London, SW7 2AZ, U.K
- Department Section of Structural and Synthetic Biology, Department of Infectious Disease; Imperial College London, South Kensington Campus, Exhibition Road, London, SW7 2AZ, U.K
| | - Soo-Mei Chee
- Department Section of Structural and Synthetic Biology, Department of Infectious Disease; Imperial College London, South Kensington Campus, Exhibition Road, London, SW7 2AZ, U.K
- The London Biofoundry, Imperial College Translation & Innovation Hub, White City Campus, 80 Wood Lane, London W12 0BZ, U.K
| | - Ming Toh
- Centre for Synthetic Biology and Innovation, Imperial College London, South Kensington Campus, Exhibition Road, London, SW7 2AZ, U.K
- Department Section of Structural and Synthetic Biology, Department of Infectious Disease; Imperial College London, South Kensington Campus, Exhibition Road, London, SW7 2AZ, U.K
| | - Seth Coode
- School of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, U.K
| | - Kameshwari Chengan
- School of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, U.K
| | - Patrick Capel
- Warwick Integrative Synthetic Biology Centre, School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, U.K
| | - Christophe Corre
- Warwick Integrative Synthetic Biology Centre, School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, U.K
| | - Emmanuel LC de los Santos
- Warwick Integrative Synthetic Biology Centre, School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, U.K
| | - Paul S. Freemont
- Centre for Synthetic Biology and Innovation, Imperial College London, South Kensington Campus, Exhibition Road, London, SW7 2AZ, U.K
- Department Section of Structural and Synthetic Biology, Department of Infectious Disease; Imperial College London, South Kensington Campus, Exhibition Road, London, SW7 2AZ, U.K
- The London Biofoundry, Imperial College Translation & Innovation Hub, White City Campus, 80 Wood Lane, London W12 0BZ, U.K
- UK Dementia Research Institute Care Research and Technology Centre, Imperial College London, Hammersmith Campus, Du Cane Road, London, W12 0N, U.K
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35
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Montalbán-López M, Scott TA, Ramesh S, Rahman IR, van Heel AJ, Viel JH, Bandarian V, Dittmann E, Genilloud O, Goto Y, Grande Burgos MJ, Hill C, Kim S, Koehnke J, Latham JA, Link AJ, Martínez B, Nair SK, Nicolet Y, Rebuffat S, Sahl HG, Sareen D, Schmidt EW, Schmitt L, Severinov K, Süssmuth RD, Truman AW, Wang H, Weng JK, van Wezel GP, Zhang Q, Zhong J, Piel J, Mitchell DA, Kuipers OP, van der Donk WA. New developments in RiPP discovery, enzymology and engineering. Nat Prod Rep 2021; 38:130-239. [PMID: 32935693 PMCID: PMC7864896 DOI: 10.1039/d0np00027b] [Citation(s) in RCA: 408] [Impact Index Per Article: 136.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Covering: up to June 2020Ribosomally-synthesized and post-translationally modified peptides (RiPPs) are a large group of natural products. A community-driven review in 2013 described the emerging commonalities in the biosynthesis of RiPPs and the opportunities they offered for bioengineering and genome mining. Since then, the field has seen tremendous advances in understanding of the mechanisms by which nature assembles these compounds, in engineering their biosynthetic machinery for a wide range of applications, and in the discovery of entirely new RiPP families using bioinformatic tools developed specifically for this compound class. The First International Conference on RiPPs was held in 2019, and the meeting participants assembled the current review describing new developments since 2013. The review discusses the new classes of RiPPs that have been discovered, the advances in our understanding of the installation of both primary and secondary post-translational modifications, and the mechanisms by which the enzymes recognize the leader peptides in their substrates. In addition, genome mining tools used for RiPP discovery are discussed as well as various strategies for RiPP engineering. An outlook section presents directions for future research.
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36
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Cole SD, Miklos AE, Chiao AC, Sun ZZ, Lux MW. Methodologies for preparation of prokaryotic extracts for cell-free expression systems. Synth Syst Biotechnol 2020; 5:252-267. [PMID: 32775710 PMCID: PMC7398980 DOI: 10.1016/j.synbio.2020.07.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 07/22/2020] [Accepted: 07/23/2020] [Indexed: 12/19/2022] Open
Abstract
Cell-free systems that mimic essential cell functions, such as gene expression, have dramatically expanded in recent years, both in terms of applications and widespread adoption. Here we provide a review of cell-extract methods, with a specific focus on prokaryotic systems. Firstly, we describe the diversity of Escherichia coli genetic strains available and their corresponding utility. We then trace the history of cell-extract methodology over the past 20 years, showing key improvements that lower the entry level for new researchers. Next, we survey the rise of new prokaryotic cell-free systems, with associated methods, and the opportunities provided. Finally, we use this historical perspective to comment on the role of methodology improvements and highlight where further improvements may be possible.
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Affiliation(s)
- Stephanie D. Cole
- US Army Combat Capabilities Development Command Chemical Biological Center, 8567 Ricketts Point Road, Aberdeen Proving Ground, MD, 21010, USA
| | - Aleksandr E. Miklos
- US Army Combat Capabilities Development Command Chemical Biological Center, 8567 Ricketts Point Road, Aberdeen Proving Ground, MD, 21010, USA
| | - Abel C. Chiao
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- Synvitrobio Inc., San Francisco, CA, USA
| | - Zachary Z. Sun
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- Synvitrobio Inc., San Francisco, CA, USA
| | - Matthew W. Lux
- US Army Combat Capabilities Development Command Chemical Biological Center, 8567 Ricketts Point Road, Aberdeen Proving Ground, MD, 21010, USA
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37
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Dopp JL, Reuel NF. Simple, functional, inexpensive cell extract for in vitro prototyping of proteins with disulfide bonds. Biochem Eng J 2020. [DOI: 10.1016/j.bej.2020.107790] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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38
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Mohr B, Giannone RJ, Hettich RL, Doktycz MJ. Targeted Growth Medium Dropouts Promote Aromatic Compound Synthesis in Crude E. coli Cell-Free Systems. ACS Synth Biol 2020; 9:2986-2997. [PMID: 33044063 DOI: 10.1021/acssynbio.9b00524] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Progress in cell-free protein synthesis (CFPS) has spurred resurgent interest in engineering complex biological metabolism outside of the cell. Unlike purified enzyme systems, crude cell-free systems can be prepared for a fraction of the cost and contain endogenous cellular pathways that can be activated for biosynthesis. Endogenous activity performs essential functions in cell-free systems including substrate biosynthesis and energy regeneration; however, use of crude cell-free systems for bioproduction has been hampered by the under-described complexity of the metabolic networks inherent to a crude lysate. Physical and chemical cultivation parameters influence the endogenous activity of the resulting lysate, but targeted efforts to engineer this activity by manipulation of these nongenetic factors has been limited. Here growth medium composition was manipulated to improve the one-pot in vitro biosynthesis of phenol from glucose via the expression of Pasteurella multocida phenol-tyrosine lyase in crude E. coli lysates. Crude cell lysate metabolic activity was focused toward the limiting precursor tyrosine by targeted growth medium dropouts guided by proteomics. The result is the activation of a 25-step enzymatic reaction cascade involving at least three endogenous E. coli metabolic pathways. Additional modification of this system, through CFPS of feedback intolerant AroG improves yield. This effort demonstrates the ability to activate a long, complex pathway in vitro and provides a framework for harnessing the metabolic potential of diverse organisms for cell-free metabolic engineering. The more than 6-fold increase in phenol yield with limited genetic manipulation demonstrates the benefits of optimizing growth medium for crude cell-free extract production and illustrates the advantages of a systems approach to cell-free metabolic engineering.
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Affiliation(s)
- Benjamin Mohr
- Bredesen Center for Interdisciplinary Research, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Richard J. Giannone
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Robert L. Hettich
- Bredesen Center for Interdisciplinary Research, University of Tennessee, Knoxville, Tennessee 37996, United States
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Mitchel J. Doktycz
- Bredesen Center for Interdisciplinary Research, University of Tennessee, Knoxville, Tennessee 37996, United States
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
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39
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Lin X, Li Y, Li Z, Hua R, Xing Y, Lu Y. Portable environment-signal detection biosensors with cell-free synthetic biosystems. RSC Adv 2020; 10:39261-39265. [PMID: 35518409 PMCID: PMC9057330 DOI: 10.1039/d0ra05293k] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 10/09/2020] [Indexed: 01/27/2023] Open
Abstract
By embedding regulated genetic circuits and cell-free systems onto a paper, the portable in vitro biosensing platform showed the possibility of detecting environmental pollutants, namely arsenic ions and bacterial quorum-sensing signal AHLs (N-acyl homoserine lactones). This platform has a great potential for practical environmental management and diagnosis. By embedding the regulated genetic circuits and cell-free systems onto a paper, a portable in vitro biosensing platform has been established.![]()
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Affiliation(s)
- Xiaomei Lin
- Key Laboratory of Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University Beijing 100084 China
| | - Yuting Li
- Key Laboratory of Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University Beijing 100084 China
| | - Zhixia Li
- Key Laboratory of Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University Beijing 100084 China
| | - Rui Hua
- Key Laboratory of Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University Beijing 100084 China
| | - Yuyang Xing
- Key Laboratory of Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University Beijing 100084 China
| | - Yuan Lu
- Key Laboratory of Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University Beijing 100084 China
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40
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Morató A, Elena-Real CA, Popovic M, Fournet A, Zhang K, Allemand F, Sibille N, Urbanek A, Bernadó P. Robust Cell-Free Expression of Sub-Pathological and Pathological Huntingtin Exon-1 for NMR Studies. General Approaches for the Isotopic Labeling of Low-Complexity Proteins. Biomolecules 2020; 10:E1458. [PMID: 33086646 PMCID: PMC7603387 DOI: 10.3390/biom10101458] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 10/07/2020] [Accepted: 10/16/2020] [Indexed: 12/23/2022] Open
Abstract
The high-resolution structural study of huntingtin exon-1 (HttEx1) has long been hampered by its intrinsic properties. In addition to being prone to aggregate, HttEx1 contains low-complexity regions (LCRs) and is intrinsically disordered, ruling out several standard structural biology approaches. Here, we use a cell-free (CF) protein expression system to robustly and rapidly synthesize (sub-) pathological HttEx1. The open nature of the CF reaction allows the application of different isotopic labeling schemes, making HttEx1 amenable for nuclear magnetic resonance studies. While uniform and selective labeling facilitate the sequential assignment of HttEx1, combining CF expression with nonsense suppression allows the site-specific incorporation of a single labeled residue, making possible the detailed investigation of the LCRs. To optimize CF suppression yields, we analyze the expression and suppression kinetics, revealing that high concentrations of loaded suppressor tRNA have a negative impact on the final reaction yield. The optimized CF protein expression and suppression system is very versatile and well suited to produce challenging proteins with LCRs in order to enable the characterization of their structure and dynamics.
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Affiliation(s)
| | | | | | | | | | | | | | - Annika Urbanek
- Centre de Biochimie Structurale (CBS), INSERM, CNRS and Université de Montpellier. 29 rue de Navacelles, 34090 Montpellier, France; (A.M.); (C.A.E.-R.); (M.P.); (A.F.); (K.Z.); (F.A.); (N.S.)
| | - Pau Bernadó
- Centre de Biochimie Structurale (CBS), INSERM, CNRS and Université de Montpellier. 29 rue de Navacelles, 34090 Montpellier, France; (A.M.); (C.A.E.-R.); (M.P.); (A.F.); (K.Z.); (F.A.); (N.S.)
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41
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Cui Z, Johnston WA, Alexandrov K. Cell-Free Approach for Non-canonical Amino Acids Incorporation Into Polypeptides. Front Bioeng Biotechnol 2020; 8:1031. [PMID: 33117774 PMCID: PMC7550873 DOI: 10.3389/fbioe.2020.01031] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 08/07/2020] [Indexed: 12/12/2022] Open
Abstract
Synthetic biology holds promise to revolutionize the life sciences and biomedicine via expansion of macromolecular diversity outside the natural chemical space. Use of non-canonical amino acids (ncAAs) via codon reassignment has found diverse applications in protein structure and interaction analysis, introduction of post-translational modifications, production of constrained peptides, antibody-drug conjugates, and novel enzymes. However, simultaneously encoding multiple ncAAs in vivo requires complex engineering and is sometimes restricted by the cell's poor uptake of ncAAs. In contrast the open nature of cell-free protein synthesis systems offers much greater freedom for manipulation and repurposing of the biosynthetic machinery by controlling the level and identity of translational components and reagents, and allows simultaneous incorporation of multiple ncAAs with non-canonical side chains and even backbones (N-methyl, D-, β-amino acids, α-hydroxy acids etc.). This review focuses on the two most used Escherichia coli-based cell-free protein synthesis systems; cell extract- and PURE-based systems. The former is a biological mixture with >500 proteins, while the latter consists of 38 individually purified biomolecules. We delineate compositions of these two systems and discuss their respective advantages and applications. Also, we dissect the translational components required for ncAA incorporation and compile lists of ncAAs that can be incorporated into polypeptides via different acylation approaches. We highlight the recent progress in using unnatural nucleobase pairs to increase the repertoire of orthogonal codons, as well as using tRNA-specific ribozymes for in situ acylation. We summarize advances in engineering of translational machinery such as tRNAs, aminoacyl-tRNA synthetases, elongation factors, and ribosomes to achieve efficient incorporation of structurally challenging ncAAs. We note that, many engineered components of biosynthetic machinery are developed for the use in vivo but are equally applicable to the in vitro systems. These are included in the review to provide a comprehensive overview for ncAA incorporation and offer new insights for the future development in cell-free systems. Finally, we highlight the exciting progress in the genomic engineering, resulting in E. coli strains free of amber and some redundant sense codons. These strains can be used for preparation of cell extracts offering multiple reassignment options.
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Affiliation(s)
- Zhenling Cui
- Synthetic Biology Laboratory, School of Biology and Environmental Science, Queensland University of Technology, Brisbane, QLD, Australia
| | - Wayne A Johnston
- Synthetic Biology Laboratory, School of Biology and Environmental Science, Queensland University of Technology, Brisbane, QLD, Australia
| | - Kirill Alexandrov
- Synthetic Biology Laboratory, School of Biology and Environmental Science, Queensland University of Technology, Brisbane, QLD, Australia
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42
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Lee MS, Hung CS, Phillips DA, Buck CC, Gupta MK, Lux MW. Silk fibroin as an additive for cell-free protein synthesis. Synth Syst Biotechnol 2020; 5:145-154. [PMID: 32637668 PMCID: PMC7320238 DOI: 10.1016/j.synbio.2020.06.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 06/15/2020] [Accepted: 06/15/2020] [Indexed: 01/06/2023] Open
Abstract
Cell-free systems contain many proteins and metabolites required for complex functions such as transcription and translation or multi-step metabolic conversions. Research into expanding the delivery of these systems by drying or by embedding into other materials is enabling new applications in sensing, point-of-need manufacturing, and responsive materials. Meanwhile, silk fibroin from the silk worm, Bombyx mori, has received attention as a protective additive for dried enzyme formulations and as a material to build biocompatible hydrogels for controlled localization or delivery of biomolecular cargoes. In this work, we explore the effects of silk fibroin as an additive in cell-free protein synthesis (CFPS) reactions. Impacts of silk fibroin on CFPS activity and stability after drying, as well as the potential for incorporation of CFPS into hydrogels of crosslinked silk fibroin are assessed. We find that simple addition of silk fibroin increased productivity of the CFPS reactions by up to 42%, which we attribute to macromolecular crowding effects. However, we did not find evidence that silk fibroin provides a protective effects after drying as previously described for purified enzymes. Further, the enzymatic crosslinking transformations of silk fibroin typically used to form hydrogels are inhibited in the presence of the CFPS reaction mixture. Crosslinking attempts did not impact CFPS activity, but did yield localized protein aggregates rather than a hydrogel. We discuss the mechanisms at play in these results and how the silk fibroin-CFPS system might be improved for the design of cell-free devices.
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Affiliation(s)
- Marilyn S. Lee
- US Army Combat Capabilities Development Command Chemical and Biological Center, 8567 Ricketts Point Road, Aberdeen Proving Ground, MD, 21010, USA
| | - Chia-Suei Hung
- US Air Force Research Laboratory, 2179 12th St., B652/R122 Wright-Patterson Air Force Base, OH, 45433, USA
| | - Daniel A. Phillips
- US Naval Research Laboratory Center for Bio/Molecular Science and Engineering, Bldg. 42, Room 303 4555 Overlook Ave. Washington, DC 20375, UES Inc., 4401 Dayton Xenia Rd., Beavercreek, OH 45432, USA
| | - Chelsea C. Buck
- US Air Force Research Laboratory, 2179 12th St., B652/R122 Wright-Patterson Air Force Base, OH, 45433, USA
- US Naval Research Laboratory Center for Bio/Molecular Science and Engineering, Bldg. 42, Room 303 4555 Overlook Ave. Washington, DC 20375, UES Inc., 4401 Dayton Xenia Rd., Beavercreek, OH 45432, USA
| | - Maneesh K. Gupta
- US Air Force Research Laboratory, 2179 12th St., B652/R122 Wright-Patterson Air Force Base, OH, 45433, USA
| | - Matthew W. Lux
- US Army Combat Capabilities Development Command Chemical and Biological Center, 8567 Ricketts Point Road, Aberdeen Proving Ground, MD, 21010, USA
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43
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Spice AJ, Aw R, Bracewell DG, Polizzi KM. Improving the reaction mix of a Pichia pastoris cell-free system using a design of experiments approach to minimise experimental effort. Synth Syst Biotechnol 2020; 5:137-144. [PMID: 32637667 PMCID: PMC7320237 DOI: 10.1016/j.synbio.2020.06.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 06/07/2020] [Accepted: 06/08/2020] [Indexed: 12/20/2022] Open
Abstract
A renaissance in cell-free protein synthesis (CFPS) is underway, enabled by the acceleration and adoption of synthetic biology methods. CFPS has emerged as a powerful platform technology for synthetic gene network design, biosensing and on-demand biomanufacturing. Whilst primarily of bacterial origin, cell-free extracts derived from a variety of host organisms have been explored, aiming to capitalise on cellular diversity and the advantageous properties associated with those organisms. However, cell-free extracts produced from eukaryotes are often overlooked due to their relatively low yields, despite the potential for improved protein folding and posttranslational modifications. Here we describe further development of a Pichia pastoris cell-free platform, a widely used expression host in both academia and the biopharmaceutical industry. Using a minimised Design of Experiments (DOE) approach, we were able to increase the productivity of the system by improving the composition of the complex reaction mixture. This was achieved in a minimal number of experimental runs, within the constraints of the design and without the need for liquid-handling robots. In doing so, we were able to estimate the main effects impacting productivity in the system and increased the protein synthesis of firefly luciferase and the biopharmaceutical HSA by 4.8-fold and 3.5-fold, respectively. This study highlights the P. pastoris-based cell-free system as a highly productive eukaryotic platform and displays the value of minimised DOE designs.
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Key Words
- AB, Albumin Blue
- CFPS, cell-free protein synthesis
- CHO, Chinese hamster ovary cells
- Cell-free protein synthesis
- DOE, design of Experiments
- DSD, definitive screening design
- Design of experiments (DOE)
- HSA, human serum albumin
- IRES, internal ribosome entry site
- Pichia pastoris
- RRL, rabbit reticulocyte lysate
- Synthetic biology
- VLP, virus-like particles
- WGE, wheat-germ etract
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Affiliation(s)
- Alex J. Spice
- Department of Chemical Engineering, Imperial College London, London, UK
- Imperial College Centre for Synthetic Biology, Imperial College London, UK
| | - Rochelle Aw
- Department of Chemical Engineering, Imperial College London, London, UK
- Imperial College Centre for Synthetic Biology, Imperial College London, UK
| | - Daniel G. Bracewell
- Department of Biochemical Engineering, University College London, London, UK
| | - Karen M. Polizzi
- Department of Chemical Engineering, Imperial College London, London, UK
- Imperial College Centre for Synthetic Biology, Imperial College London, UK
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44
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Lee MS, Raig RM, Gupta MK, Lux MW. Lyophilized Cell-Free Systems Display Tolerance to Organic Solvent Exposure. ACS Synth Biol 2020; 9:1951-1957. [PMID: 32646213 DOI: 10.1021/acssynbio.0c00267] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Cell-free systems offer a powerful way to deliver biochemical activity to the field without cold chain storage. These systems are capable of sensing as well as biosynthesis of useful molecules at the point of need. So far, cell-free protein synthesis (CFPS) reactions have been studied as aqueous solutions in test tubes or absorbed into paper or cloth. Embedding biological functionality into broadly used materials, such as plastic polymers, represents an attractive goal. Unfortunately, this goal has for the most part remained out of reach, presumably due to the fragility of biological systems outside of aqueous environments. Here, we describe a surprising and useful feature of lyophilized cell-free lysate systems: tolerance to a variety of organic solvents. Screens of individual CFPS reagents and different CFPS methods reveal that solvent tolerance varies by CFPS reagent composition. Tolerance to suspension in organic solvents may facilitate the use of polymers to deliver dry cell-free reactions in the form of coatings or fibers, or allow dosing of analytes or substrates dissolved in nonaqueous solvents, among other processing possibilities.
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Affiliation(s)
- Marilyn S. Lee
- US Army Combat Capabilities Development Command Chemical and Biological Center, 8567 Ricketts Point Road, Aberdeen Proving Ground, Maryland 21010, United States
| | - Rebecca M. Raig
- US Air Force Research Laboratory, 2179 12th Street, B652/R122 Wright-Patterson Air Force Base, Ohio 45433, United States
- UES Inc., 4401 Dayton-Xenia Road, Dayton, Ohio 45432, United States
| | - Maneesh K. Gupta
- US Air Force Research Laboratory, 2179 12th Street, B652/R122 Wright-Patterson Air Force Base, Ohio 45433, United States
| | - Matthew W. Lux
- US Army Combat Capabilities Development Command Chemical and Biological Center, 8567 Ricketts Point Road, Aberdeen Proving Ground, Maryland 21010, United States
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45
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Williams LC, Gregorio NE, So B, Kao WY, Kiste AL, Patel PA, Watts KR, Oza JP. The Genetic Code Kit: An Open-Source Cell-Free Platform for Biochemical and Biotechnology Education. Front Bioeng Biotechnol 2020; 8:941. [PMID: 32974303 PMCID: PMC7466673 DOI: 10.3389/fbioe.2020.00941] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 07/21/2020] [Indexed: 01/06/2023] Open
Abstract
Teaching the processes of transcription and translation is challenging due to the intangibility of these concepts and a lack of instructional, laboratory-based, active learning modules. Harnessing the genetic code in vitro with cell-free protein synthesis (CFPS) provides an open platform that allows for the direct manipulation of reaction conditions and biological machinery to enable inquiry-based learning. Here, we report our efforts to transform the research-based CFPS biotechnology into a hands-on module called the “Genetic Code Kit” for implementation into teaching laboratories. The Genetic Code Kit includes all reagents necessary for CFPS, as well as a laboratory manual, student worksheet, and augmented reality activity. This module allows students to actively explore transcription and translation while gaining exposure to an emerging research technology. In our testing of this module, undergraduate students who used the Genetic Code Kit in a teaching laboratory showed significant score increases on transcription and translation questions in a post-lab questionnaire compared with students who did not participate in the activity. Students also demonstrated an increase in self-reported confidence in laboratory methods and comfort with CFPS, indicating that this module helps prepare students for careers in laboratory research. Importantly, the Genetic Code Kit can accommodate a variety of learning objectives beyond transcription and translation and enables hypothesis-driven science. This opens the possibility of developing Course-Based Undergraduate Research Experiences (CUREs) based on the Genetic Code Kit, as well as supporting next-generation science standards in 8–12th grade science courses.
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Affiliation(s)
- Layne C Williams
- Department of Chemistry & Biochemistry, California Polytechnic State University, San Luis Obispo, CA, United States.,Center for Applications in Biotechnology, California Polytechnic State University, San Luis Obispo, CA, United States
| | - Nicole E Gregorio
- Department of Chemistry & Biochemistry, California Polytechnic State University, San Luis Obispo, CA, United States.,Center for Applications in Biotechnology, California Polytechnic State University, San Luis Obispo, CA, United States
| | - Byungcheol So
- Department of Chemistry & Biochemistry, California Polytechnic State University, San Luis Obispo, CA, United States.,Center for Applications in Biotechnology, California Polytechnic State University, San Luis Obispo, CA, United States
| | - Wesley Y Kao
- Department of Chemistry & Biochemistry, California Polytechnic State University, San Luis Obispo, CA, United States.,Center for Applications in Biotechnology, California Polytechnic State University, San Luis Obispo, CA, United States
| | - Alan L Kiste
- Department of Chemistry & Biochemistry, California Polytechnic State University, San Luis Obispo, CA, United States
| | - Pratish A Patel
- Department of Finance, Orfalea College of Business, California Polytechnic State University, San Luis Obispo, CA, United States
| | - Katharine R Watts
- Department of Chemistry & Biochemistry, California Polytechnic State University, San Luis Obispo, CA, United States.,Center for Applications in Biotechnology, California Polytechnic State University, San Luis Obispo, CA, United States
| | - Javin P Oza
- Department of Chemistry & Biochemistry, California Polytechnic State University, San Luis Obispo, CA, United States.,Center for Applications in Biotechnology, California Polytechnic State University, San Luis Obispo, CA, United States
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46
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Colant N, Melinek B, Teneb J, Goldrick S, Rosenberg W, Frank S, Bracewell DG. A rational approach to improving titer in Escherichia coli-based cell-free protein synthesis reactions. Biotechnol Prog 2020; 37:e3062. [PMID: 32761750 DOI: 10.1002/btpr.3062] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 07/14/2020] [Accepted: 07/30/2020] [Indexed: 02/06/2023]
Abstract
Cell-free protein synthesis (CFPS) is an established method for rapid recombinant protein production. Advantages like short synthesis times and an open reaction environment make CFPS a desirable platform for new and difficult-to-express products. Most recently, interest has grown in using the technology to make larger amounts of material. This has been driven through a variety of reasons from making site specific antibody drug conjugates, to emergency response, to the safe manufacture of toxic biological products. We therefore need robust methods to determine the appropriate reaction conditions for product expression in CFPS. Here we propose a process development strategy for Escherichia coli lysate-based CFPS reactions that can be completed in as little as 48 hr. We observed the most dramatic increases in titer were due to the E. coli strain for the cell extract. Therefore, we recommend identifying a high-producing cell extract for the product of interest as a first step. Next, we manipulated the plasmid concentration, amount of extract, temperature, concentrated reaction mix pH levels, and length of reaction. The influence of these process parameters on titer was evaluated through multivariate data analysis. The process parameters with the highest impact on titer were subsequently included in a design of experiments to determine the conditions that increased titer the most in the design space. This proposed process development strategy resulted in superfolder green fluorescent protein titers of 0.686 g/L, a 38% improvement on the standard operating conditions, and hepatitis B core antigen titers of 0.386 g/L, a 190% improvement.
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Affiliation(s)
- Noelle Colant
- Department of Biochemical Engineering, University College London, London, UK
| | - Beatrice Melinek
- Department of Biochemical Engineering, University College London, London, UK
| | - Jaime Teneb
- Department of Biochemical Engineering, University College London, London, UK
| | - Stephen Goldrick
- Department of Biochemical Engineering, University College London, London, UK
| | - William Rosenberg
- UCL Institute for Liver and Digestive Health, Division of Medicine, Royal Free Campus, London, UK
| | - Stefanie Frank
- Department of Biochemical Engineering, University College London, London, UK
| | - Daniel G Bracewell
- Department of Biochemical Engineering, University College London, London, UK
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47
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Wu Y, Wang Z, Qiao X, Li J, Shu X, Qi H. Emerging Methods for Efficient and Extensive Incorporation of Non-canonical Amino Acids Using Cell-Free Systems. Front Bioeng Biotechnol 2020; 8:863. [PMID: 32793583 PMCID: PMC7387428 DOI: 10.3389/fbioe.2020.00863] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 07/06/2020] [Indexed: 12/17/2022] Open
Abstract
Cell-free protein synthesis (CFPS) has emerged as a novel protein expression platform. Especially the incorporation of non-canonical amino acids (ncAAs) has led to the development of numerous flexible methods for efficient and extensive expression of artificial proteins. Approaches were developed to eliminate the endogenous competition for ncAAs and engineer translation factors, which significantly enhanced the incorporation efficiency. Furthermore, in vitro aminoacylation methods can be conveniently combined with cell-free systems, extensively expanding the available ncAAs with novel and unique moieties. In this review, we summarize the recent progresses on the efficient and extensive incorporation of ncAAs by different strategies based on the elimination of competition by endogenous factors, translation factors engineering and extensive incorporation of novel ncAAs coupled with in vitro aminoacylation methods in CFPS. We also aim to offer new ideas to researchers working on ncAA incorporation techniques in CFPS and applications in various emerging fields.
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Affiliation(s)
- Yang Wu
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University, Tianjin, China
| | - Zhaoguan Wang
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University, Tianjin, China
| | - Xin Qiao
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University, Tianjin, China
| | - Jiaojiao Li
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University, Tianjin, China
| | - Xiangrong Shu
- Department of Pharmacy, Tianjin Huanhu Hospital, Tianjin, China
| | - Hao Qi
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University, Tianjin, China
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48
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Chen X, Sun Q, Lu Y. Creating a locally crowded environment with nanoclay hydrogels for cell-free biosynthesis. SOFT MATTER 2020; 16:5132-5138. [PMID: 32478769 DOI: 10.1039/d0sm00636j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In living cells, the exceptionally high local concentration of macromolecules, or "locally crowded environment," could affect many aspects of cellular function. Exploration of the locally crowded environment can improve the understanding of living cells and advance the study of artificial cells. In this paper, nanoclay combined with gene templates is used to simulate the locally crowded environment in a cell-free system, ultimately to explore its effects on protein expression. The adsorption effect can immobilize the plasmid on the nanoclay surface, thereby achieving a higher local concentration in the cell-free system. A closer proximity of genes could result in an increase in the protein production of cell-free systems by 1.75 times. Besides, the kinetics of the nanoclay in the cell-free system was analyzed, and the results showed that the genetic transcription level involved in cell-free reactions was significantly improved. This study confirms that a locally crowded environment created by the nanoclay can achieve high protein expression in a cell-free system and help promote the process of transcription and translation. Application of the nanoclay in the cell-free system demonstrates the significance of applying nanomaterials in biological and biomedical fields and provides technical support for the study of the locally crowded environment.
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Affiliation(s)
- Xinjie Chen
- Key Laboratory of Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China.
| | - Qi Sun
- Key Laboratory of Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China.
| | - Yuan Lu
- Key Laboratory of Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China.
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49
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Abstract
The cell-free molecular synthesis of biochemical systems is a rapidly growing field of research. Advances in the Human Genome Project, DNA synthesis, and other technologies have allowed the in vitro construction of biochemical systems, termed cell-free biology, to emerge as an exciting domain of bioengineering. Cell-free biology ranges from the molecular to the cell-population scales, using an ever-expanding variety of experimental platforms and toolboxes. In this review, we discuss the ongoing efforts undertaken in the three major classes of cell-free biology methodologies, namely protein-based, nucleic acids–based, and cell-free transcription–translation systems, and provide our perspectives on the current challenges as well as the major goals in each of the subfields.
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Affiliation(s)
- Vincent Noireaux
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Allen P. Liu
- Departments of Mechanical Engineering, Biomedical Engineering, Biophysics, and the Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan 48109, USA
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50
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Dopp JL, Jo YR, Reuel NF. Methods to reduce variability in E. Coli-based cell-free protein expression experiments. Synth Syst Biotechnol 2019; 4:204-211. [PMID: 31750411 PMCID: PMC6849339 DOI: 10.1016/j.synbio.2019.10.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 10/21/2019] [Accepted: 10/24/2019] [Indexed: 12/23/2022] Open
Abstract
Cell-free protein synthesis (CFPS) is an established biotechnology tool that has shown great utility in many applications such as prototyping proteins, building genetic circuits, designing biosensors, and expressing cytotoxic proteins. Although CFPS has been widely deployed, the many, varied methods presented in the literature can be challenging for new users to adopt. From our experience and others who newly enter the field, one of the most frustrating aspects of applying CFPS as a laboratory can be the large levels of variability that are present within experimental replicates. Herein we provide a retrospective summary of CFPS methods that reduce variability significantly. These methods include optimized extract preparation, fully solubilizing the master mix components, and careful mixing of the reaction. These have reduced our coefficient of variation from 97.3% to 1.2%. Moreover, these methods allow complete novices (e.g. semester rotation undergraduate students) to provide data that is comparable to experienced users, thus allowing broader participation in this exciting research area.
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