1
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Wu J, Liang C, Li Y, Zeng Y, Sun X, Jiang P, Chen W, Xiong D, Jin J, Tang S. Engineering and application of LacI mutants with stringent expressions. Microb Biotechnol 2024; 17:e14427. [PMID: 38465475 PMCID: PMC10926051 DOI: 10.1111/1751-7915.14427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 01/30/2024] [Accepted: 02/05/2024] [Indexed: 03/12/2024] Open
Abstract
Optimal transcriptional regulatory circuits are expected to exhibit stringent control, maintaining silence in the absence of inducers while exhibiting a broad induction dynamic range upon the addition of effectors. In the Plac /LacI pair, the promoter of the lac operon in Escherichia coli is characterized by its leakiness, attributed to the moderate affinity of LacI for its operator target. In response to this limitation, the LacI regulatory protein underwent engineering to enhance its regulatory properties. The M7 mutant, carrying I79T and N246S mutations, resulted in the lac promoter displaying approximately 95% less leaky expression and a broader induction dynamic range compared to the wild-type LacI. An in-depth analysis of each mutation revealed distinct regulatory profiles. In contrast to the wild-type LacI, the M7 mutant exhibited a tighter binding to the operator sequence, as evidenced by surface plasmon resonance studies. Leveraging the capabilities of the M7 mutant, a high-value sugar biosensor was constructed. This biosensor facilitated the selection of mutant galactosidases with approximately a seven-fold improvement in specific activity for transgalactosylation. Consequently, this advancement enabled enhanced biosynthesis of galacto-oligosaccharides (GOS).
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Affiliation(s)
- Jieyuan Wu
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial ResourcesInstitute of Microbiology, Chinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Chaoning Liang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial ResourcesInstitute of Microbiology, Chinese Academy of SciencesBeijingChina
| | - Yufei Li
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial ResourcesInstitute of Microbiology, Chinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Yueting Zeng
- School of Life SciencesHebei UniversityBaodingChina
| | - Xu Sun
- Beijing Key Laboratory of Plant Resources Research and DevelopmentBeijing Technology and Business UniversityBeijingChina
| | - Peixia Jiang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial ResourcesInstitute of Microbiology, Chinese Academy of SciencesBeijingChina
| | - Wei Chen
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial ResourcesInstitute of Microbiology, Chinese Academy of SciencesBeijingChina
| | - Dandan Xiong
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial ResourcesInstitute of Microbiology, Chinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Jian‐Ming Jin
- Beijing Key Laboratory of Plant Resources Research and DevelopmentBeijing Technology and Business UniversityBeijingChina
| | - Shuang‐Yan Tang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial ResourcesInstitute of Microbiology, Chinese Academy of SciencesBeijingChina
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2
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Hersey AN, Kay VE, Lee S, Realff MJ, Wilson CJ. Engineering allosteric transcription factors guided by the LacI topology. Cell Syst 2023; 14:645-655. [PMID: 37591203 DOI: 10.1016/j.cels.2023.04.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 02/26/2023] [Accepted: 04/26/2023] [Indexed: 08/19/2023]
Abstract
Allosteric transcription factors (aTFs) are used in a myriad of processes throughout biology and biotechnology. aTFs have served as the workhorses for developments in synthetic biology, fundamental research, and protein manufacturing. One of the most utilized TFs is the lactose repressor (LacI). In addition to being an exceptional tool for gene regulation, LacI has also served as an outstanding model system for understanding allosteric communication. In this perspective, we will use the LacI TF as the principal exemplar for engineering alternate functions related to allostery-i.e., alternate protein DNA interactions, alternate protein-ligand interactions, and alternate phenotypic mechanisms. In addition, we will summarize the design rules and heuristics for each design goal and demonstrate how the resulting design rules and heuristics can be extrapolated to engineer other aTFs with a similar topology-i.e., from the broader LacI/GalR family of TFs.
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Affiliation(s)
- Ashley N Hersey
- Georgia Institute of Technology, School of Chemical & Biomolecular Engineering, Atlanta, GA, USA
| | - Valerie E Kay
- Georgia Institute of Technology, School of Chemical & Biomolecular Engineering, Atlanta, GA, USA
| | - Sumin Lee
- Georgia Institute of Technology, School of Chemical & Biomolecular Engineering, Atlanta, GA, USA
| | - Matthew J Realff
- Georgia Institute of Technology, School of Chemical & Biomolecular Engineering, Atlanta, GA, USA
| | - Corey J Wilson
- Georgia Institute of Technology, School of Chemical & Biomolecular Engineering, Atlanta, GA, USA.
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3
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Tack DS, Tonner PD, Pressman A, Olson ND, Levy SF, Romantseva EF, Alperovich N, Vasilyeva O, Ross D. Precision engineering of biological function with large-scale measurements and machine learning. PLoS One 2023; 18:e0283548. [PMID: 36989327 PMCID: PMC10057847 DOI: 10.1371/journal.pone.0283548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 03/11/2023] [Indexed: 03/30/2023] Open
Abstract
As synthetic biology expands and accelerates into real-world applications, methods for quantitatively and precisely engineering biological function become increasingly relevant. This is particularly true for applications that require programmed sensing to dynamically regulate gene expression in response to stimuli. However, few methods have been described that can engineer biological sensing with any level of quantitative precision. Here, we present two complementary methods for precision engineering of genetic sensors: in silico selection and machine-learning-enabled forward engineering. Both methods use a large-scale genotype-phenotype dataset to identify DNA sequences that encode sensors with quantitatively specified dose response. First, we show that in silico selection can be used to engineer sensors with a wide range of dose-response curves. To demonstrate in silico selection for precise, multi-objective engineering, we simultaneously tune a genetic sensor's sensitivity (EC50) and saturating output to meet quantitative specifications. In addition, we engineer sensors with inverted dose-response and specified EC50. Second, we demonstrate a machine-learning-enabled approach to predictively engineer genetic sensors with mutation combinations that are not present in the large-scale dataset. We show that the interpretable machine learning results can be combined with a biophysical model to engineer sensors with improved inverted dose-response curves.
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Affiliation(s)
- Drew S Tack
- National Institute of Standards and Technology, Gaithersburg, MD, United States of America
| | - Peter D Tonner
- National Institute of Standards and Technology, Gaithersburg, MD, United States of America
| | - Abe Pressman
- National Institute of Standards and Technology, Gaithersburg, MD, United States of America
| | - Nathan D Olson
- National Institute of Standards and Technology, Gaithersburg, MD, United States of America
| | - Sasha F Levy
- SLAC National Accelerator Laboratory, Menlo Park, CA, United States of America
- Joint Initiative for Metrology in Biology, Stanford, CA, United States of America
| | - Eugenia F Romantseva
- National Institute of Standards and Technology, Gaithersburg, MD, United States of America
| | - Nina Alperovich
- National Institute of Standards and Technology, Gaithersburg, MD, United States of America
| | - Olga Vasilyeva
- National Institute of Standards and Technology, Gaithersburg, MD, United States of America
| | - David Ross
- National Institute of Standards and Technology, Gaithersburg, MD, United States of America
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4
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Biological signal processing filters via engineering allosteric transcription factors. Proc Natl Acad Sci U S A 2021; 118:2111450118. [PMID: 34772815 PMCID: PMC8609624 DOI: 10.1073/pnas.2111450118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/08/2021] [Indexed: 11/18/2022] Open
Abstract
As the size and complexity of genetic circuits increases, scientists and engineers need to find solutions to rapidly optimize flux and reduce the metabolic burden imposed on chassis cells. In this study, we report synthetic biology tools that imbue chassis cells with advanced signal processing functions akin to electrical devices commonly used in wireless transmitters and receivers (i.e., biological BANDPASS and BANDSTOP devices) that can simultaneously reduce metabolic burden. Moreover, this study presents a set of granular and more complete design rules for engineering allosteric transcription factors in the broader LacI/GalR topology. In addition, this study has improved our fundamental understanding of the plasticity and continuum of allosteric communication from the binding pocket to the protein–DNA interaction. Signal processing is critical to a myriad of biological phenomena (natural and engineered) that involve gene regulation. Biological signal processing can be achieved by way of allosteric transcription factors. In canonical regulatory systems (e.g., the lactose repressor), an INPUT signal results in the induction of a given transcription factor and objectively switches gene expression from an OFF state to an ON state. In such biological systems, to revert the gene expression back to the OFF state requires the aggressive dilution of the input signal, which can take 1 or more d to achieve in a typical biotic system. In this study, we present a class of engineered allosteric transcription factors capable of processing two-signal INPUTS, such that a sequence of INPUTS can rapidly transition gene expression between alternating OFF and ON states. Here, we present two fundamental biological signal processing filters, BANDPASS and BANDSTOP, that are regulated by D-fucose and isopropyl-β-D-1-thiogalactopyranoside. BANDPASS signal processing filters facilitate OFF–ON–OFF gene regulation. Whereas, BANDSTOP filters facilitate the antithetical gene regulation, ON–OFF–ON. Engineered signal processing filters can be directed to seven orthogonal promoters via adaptive modular DNA binding design. This collection of signal processing filters can be used in collaboration with our established transcriptional programming structure. Kinetic studies show that our collection of signal processing filters can switch between states of gene expression within a few minutes with minimal metabolic burden—representing a paradigm shift in general gene regulation.
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5
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Tominaga M, Nozaki K, Umeno D, Ishii J, Kondo A. Robust and flexible platform for directed evolution of yeast genetic switches. Nat Commun 2021; 12:1846. [PMID: 33758180 PMCID: PMC7988172 DOI: 10.1038/s41467-021-22134-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 02/26/2021] [Indexed: 01/31/2023] Open
Abstract
A wide repertoire of genetic switches has accelerated prokaryotic synthetic biology, while eukaryotic synthetic biology has lagged in the model organism Saccharomyces cerevisiae. Eukaryotic genetic switches are larger and more complex than prokaryotic ones, complicating the rational design and evolution of them. Here, we present a robust workflow for the creation and evolution of yeast genetic switches. The selector system was designed so that both ON- and OFF-state selection of genetic switches is completed solely by liquid handling, and it enabled parallel screen/selection of different motifs with different selection conditions. Because selection threshold of both ON- and OFF-state selection can be flexibly tuned, the desired selection conditions can be rapidly pinned down for individual directed evolution experiments without a prior knowledge either on the library population. The system's utility was demonstrated using 20 independent directed evolution experiments, yielding genetic switches with elevated inducer sensitivities, inverted switching behaviours, sensory functions, and improved signal-to-noise ratio (>100-fold induction). The resulting yeast genetic switches were readily integrated, in a plug-and-play manner, into an AND-gated carotenoid biosynthesis pathway.
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Affiliation(s)
- Masahiro Tominaga
- grid.31432.370000 0001 1092 3077Graduate School of Science, Technology and Innovation, Kobe University, Kobe, Japan
| | - Kenta Nozaki
- grid.31432.370000 0001 1092 3077Graduate School of Science, Technology and Innovation, Kobe University, Kobe, Japan
| | - Daisuke Umeno
- grid.136304.30000 0004 0370 1101Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University, Chiba, Japan
| | - Jun Ishii
- grid.31432.370000 0001 1092 3077Graduate School of Science, Technology and Innovation, Kobe University, Kobe, Japan ,grid.31432.370000 0001 1092 3077Engineering Biology Research Center, Kobe University, Kobe, Japan
| | - Akihiko Kondo
- grid.31432.370000 0001 1092 3077Graduate School of Science, Technology and Innovation, Kobe University, Kobe, Japan ,grid.31432.370000 0001 1092 3077Engineering Biology Research Center, Kobe University, Kobe, Japan ,grid.31432.370000 0001 1092 3077Department of Chemical Science and Engineering, Faculty of Engineering, Kobe University, Kobe, Japan ,grid.7597.c0000000094465255Center for Sustainable Resource Science, RIKEN, Yokohama, Japan
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6
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Rondon R, Wilson CJ. Engineering Alternate Ligand Recognition in the PurR Topology: A System of Novel Caffeine Biosensing Transcriptional Antirepressors. ACS Synth Biol 2021; 10:552-565. [PMID: 33689294 DOI: 10.1021/acssynbio.0c00582] [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: 01/05/2023]
Abstract
Recent advances in synthetic biology and protein engineering have increased the number of allosteric transcription factors used to regulate independent promoters. These developments represent an important increase in our biological computing capacity, which will enable us to construct more sophisticated genetic programs for a broad range of biological technologies. However, the majority of these transcription factors are represented by the repressor phenotype (BUFFER), and require layered inversion to confer the antithetical logical function (NOT), requiring additional biological resources. Moreover, these engineered transcription factors typically utilize native ligand binding functions paired with alternate DNA binding functions. In this study, we have advanced the state-of-the-art by engineering and redesigning the PurR topology (a native antirepressor) to be responsive to caffeine, while mitigating responsiveness to the native ligand hypoxanthine-i.e., a deamination product of the input molecule adenine. Importantly, the resulting caffeine responsive transcription factors are not antagonized by the native ligand hypoxanthine. In addition, we conferred alternate DNA binding to the caffeine antirepressors, and to the PurR scaffold, creating 38 new transcription factors that are congruent with our current transcriptional programming structure. Finally, we leveraged this system of transcription factors to create integrated NOR logic and related feedback operations. This study represents the first example of a system of transcription factors (antirepressors) in which both the ligand binding site and the DNA binding functions were successfully engineered in tandem.
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Affiliation(s)
- Ronald Rondon
- Georgia Institute of Technology, School of Chemical & Biomolecular Engineering, 311 Ferst Drive, Atlanta, Georgia 30332-0100, United States
| | - Corey J. Wilson
- Georgia Institute of Technology, School of Chemical & Biomolecular Engineering, 311 Ferst Drive, Atlanta, Georgia 30332-0100, United States
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7
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Tack DS, Tonner PD, Pressman A, Olson ND, Levy SF, Romantseva EF, Alperovich N, Vasilyeva O, Ross D. The genotype-phenotype landscape of an allosteric protein. Mol Syst Biol 2021; 17:e10179. [PMID: 33784029 PMCID: PMC8009258 DOI: 10.15252/msb.202010179] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 02/15/2021] [Accepted: 02/18/2021] [Indexed: 12/18/2022] Open
Abstract
Allostery is a fundamental biophysical mechanism that underlies cellular sensing, signaling, and metabolism. Yet a quantitative understanding of allosteric genotype-phenotype relationships remains elusive. Here, we report the large-scale measurement of the genotype-phenotype landscape for an allosteric protein: the lac repressor from Escherichia coli, LacI. Using a method that combines long-read and short-read DNA sequencing, we quantitatively measure the dose-response curves for nearly 105 variants of the LacI genetic sensor. The resulting data provide a quantitative map of the effect of amino acid substitutions on LacI allostery and reveal systematic sequence-structure-function relationships. We find that in many cases, allosteric phenotypes can be quantitatively predicted with additive or neural-network models, but unpredictable changes also occur. For example, we were surprised to discover a new band-stop phenotype that challenges conventional models of allostery and that emerges from combinations of nearly silent amino acid substitutions.
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Affiliation(s)
- Drew S Tack
- National Institute of Standards and TechnologyGaithersburgMDUSA
| | - Peter D Tonner
- National Institute of Standards and TechnologyGaithersburgMDUSA
| | - Abe Pressman
- National Institute of Standards and TechnologyGaithersburgMDUSA
| | - Nathan D Olson
- National Institute of Standards and TechnologyGaithersburgMDUSA
| | - Sasha F Levy
- SLAC National Accelerator LaboratoryMenlo ParkCAUSA
- Joint Initiative for Metrology in BiologyStanfordCAUSA
| | | | - Nina Alperovich
- National Institute of Standards and TechnologyGaithersburgMDUSA
| | - Olga Vasilyeva
- National Institute of Standards and TechnologyGaithersburgMDUSA
| | - David Ross
- National Institute of Standards and TechnologyGaithersburgMDUSA
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8
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Groseclose TM, Rondon RE, Hersey AN, Milner PT, Kim D, Zhang F, Realff MJ, Wilson CJ. Biomolecular Systems Engineering: Unlocking the Potential of Engineered Allostery via the Lactose Repressor Topology. Annu Rev Biophys 2021; 50:303-321. [PMID: 33606944 DOI: 10.1146/annurev-biophys-090820-101708] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Allosteric function is a critical component of many of the parts used to construct gene networks throughout synthetic biology. In this review, we discuss an emerging field of research and education, biomolecular systems engineering, that expands on the synthetic biology edifice-integrating workflows and strategies from protein engineering, chemical engineering, electrical engineering, and computer science principles. We focus on the role of engineered allosteric communication as it relates to transcriptional gene regulators-i.e., transcription factors and corresponding unit operations. In this review, we (a) explore allosteric communication in the lactose repressor LacI topology, (b) demonstrate how to leverage this understanding of allostery in the LacI system to engineer non-natural BUFFER and NOT logical operations, (c) illustrate how engineering workflows can be used to confer alternate allosteric functions in disparate systems that share the LacI topology, and (d) demonstrate how fundamental unit operations can be directed to form combinational logical operations.
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Affiliation(s)
- Thomas M Groseclose
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA;
| | - Ronald E Rondon
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA;
| | - Ashley N Hersey
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA;
| | - Prasaad T Milner
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA;
| | - Dowan Kim
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA;
| | - Fumin Zhang
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Matthew J Realff
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA;
| | - Corey J Wilson
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA;
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9
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Engineered protein switches for exogenous control of gene expression. Biochem Soc Trans 2020; 48:2205-2212. [DOI: 10.1042/bst20200441] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 09/28/2020] [Accepted: 09/30/2020] [Indexed: 02/02/2023]
Abstract
There is an ongoing need in the synthetic biology community for novel ways to regulate gene expression. Protein switches, which sense biological inputs and respond with functional outputs, represent one way to meet this need. Despite the fact that there is already a large pool of transcription factors and signaling proteins available, the pool of existing switches lacks the substrate specificities and activities required for certain applications. Therefore, a large number of techniques have been applied to engineer switches with novel properties. Here we discuss some of these techniques by broadly organizing them into three approaches. We show how novel switches can be created through mutagenesis, domain swapping, or domain insertion. We then briefly discuss their use as biosensors and in complex genetic circuits.
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10
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Engineered systems of inducible anti-repressors for the next generation of biological programming. Nat Commun 2020; 11:4440. [PMID: 32895374 PMCID: PMC7477573 DOI: 10.1038/s41467-020-18302-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 08/07/2020] [Indexed: 01/14/2023] Open
Abstract
Traditionally engineered genetic circuits have almost exclusively used naturally occurring transcriptional repressors. Recently, non-natural transcription factors (repressors) have been engineered and employed in synthetic biology with great success. However, transcriptional anti-repressors have largely been absent with regard to the regulation of genes in engineered genetic circuits. Here, we present a workflow for engineering systems of non-natural anti-repressors. In this study, we create 41 inducible anti-repressors. This collection of transcription factors respond to two distinct ligands, fructose (anti-FruR) or D-ribose (anti-RbsR); and were complemented by 14 additional engineered anti-repressors that respond to the ligand isopropyl β-d-1-thiogalactopyranoside (anti-LacI). In turn, we use this collection of anti-repressors and complementary genetic architectures to confer logical control over gene expression. Here, we achieved all NOT oriented logical controls (i.e., NOT, NOR, NAND, and XNOR). The engineered transcription factors and corresponding series, parallel, and series-parallel genetic architectures represent a nascent anti-repressor based transcriptional programming structure. Transcriptional anti-repressors have been largely absent in the design of regulated genetic circuits. Here, the authors present a workflow of the engineering of non-natural anti-reperssors that can be built into NOT oriented logic gates.
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11
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Engineering allosteric communication. Curr Opin Struct Biol 2020; 63:115-122. [DOI: 10.1016/j.sbi.2020.05.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 05/06/2020] [Accepted: 05/08/2020] [Indexed: 11/18/2022]
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12
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Snoek T, Chaberski EK, Ambri F, Kol S, Bjørn SP, Pang B, Barajas JF, Welner DH, Jensen MK, Keasling JD. Evolution-guided engineering of small-molecule biosensors. Nucleic Acids Res 2020; 48:e3. [PMID: 31777933 PMCID: PMC6943132 DOI: 10.1093/nar/gkz954] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 10/06/2019] [Accepted: 10/24/2019] [Indexed: 11/14/2022] Open
Abstract
Allosteric transcription factors (aTFs) have proven widely applicable for biotechnology and synthetic biology as ligand-specific biosensors enabling real-time monitoring, selection and regulation of cellular metabolism. However, both the biosensor specificity and the correlation between ligand concentration and biosensor output signal, also known as the transfer function, often needs to be optimized before meeting application needs. Here, we present a versatile and high-throughput method to evolve prokaryotic aTF specificity and transfer functions in a eukaryote chassis, namely baker's yeast Saccharomyces cerevisiae. From a single round of mutagenesis of the effector-binding domain (EBD) coupled with various toggled selection regimes, we robustly select aTF variants of the cis,cis-muconic acid-inducible transcription factor BenM evolved for change in ligand specificity, increased dynamic output range, shifts in operational range, and a complete inversion-of-function from activation to repression. Importantly, by targeting only the EBD, the evolved biosensors display DNA-binding affinities similar to BenM, and are functional when ported back into a prokaryotic chassis. The developed platform technology thus leverages aTF evolvability for the development of new host-agnostic biosensors with user-defined small-molecule specificities and transfer functions.
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Affiliation(s)
- Tim Snoek
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Evan K Chaberski
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Francesca Ambri
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Stefan Kol
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Sara P Bjørn
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Bo Pang
- Joint BioEnergy Institute, Emeryville, CA, USA
| | | | - Ditte H Welner
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Michael K Jensen
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Jay D Keasling
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark.,Joint BioEnergy Institute, Emeryville, CA, USA.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,Department of Chemical and Biomolecular Engineering & Department of Bioengineering, University of California, Berkeley, CA, USA.,Center for Synthetic Biochemistry, Institute for Synthetic Biology, Shenzhen Institutes of Advanced Technologies, Shenzhen, China
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13
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Functional tunability from a distance: Rheostat positions influence allosteric coupling between two distant binding sites. Sci Rep 2019; 9:16957. [PMID: 31740686 PMCID: PMC6861286 DOI: 10.1038/s41598-019-53464-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 10/24/2019] [Indexed: 11/27/2022] Open
Abstract
For protein mutagenesis, a common expectation is that important positions will behave like on/off “toggle” switches (i.e., a few substitutions act like wildtype, most abolish function). However, there exists another class of important positions that manifests a wide range of functional outcomes upon substitution: “rheostat” positions. Previously, we evaluated rheostat positions located near the allosteric binding sites for inhibitor alanine (Ala) and activator fructose-1,6-bisphosphate (Fru-1,6-BP) in human liver pyruvate kinase. When substituted with multiple amino acids, many positions demonstrated moderate rheostatic effects on allosteric coupling between effector binding and phosphoenolpyruvate (PEP) binding in the active site. Nonetheless, the combined outcomes of all positions sampled the full range of possible allosteric coupling (full tunability). However, that study only evaluated allosteric tunability of “local” positions, i.e., positions were located near the binding sites of the allosteric ligand being assessed. Here, we evaluated tunability of allosteric coupling when mutated sites were distant from the allosterically-coupled binding sites. Positions near the Ala binding site had rheostatic outcomes on allosteric coupling between Fru-1,6-BP and PEP binding. In contrast, positions in the Fru-1,6-BP site exhibited modest effects on coupling between Ala and PEP binding. Analyzed in aggregate, both PEP/Ala and PEP/Fru-1,6-BP coupling were again fully tunable by amino acid substitutions at this limited set of distant positions. Furthermore, some positions exhibited rheostatic control over multiple parameters and others exhibited rheostatic effects on one parameter and toggle control over a second. These findings highlight challenges in efforts to both predict/interpret mutational outcomes and engineer functions into proteins.
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14
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Rondon RE, Wilson CJ. Engineering a New Class of Anti-LacI Transcription Factors with Alternate DNA Recognition. ACS Synth Biol 2019; 8:307-317. [PMID: 30601657 DOI: 10.1021/acssynbio.8b00324] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The lactose repressor, LacI (I+YQR), is an archetypal transcription factor that has been a workhorse in many synthetic genetic networks. LacI represses gene expression (apo ligand) and is induced upon binding of the ligand isopropyl β-d-1-thiogalactopyranoside (IPTG). Recently, laboratory evolution was used to confer inverted function in the native LacI topology resulting in anti-LacI (antilac) function (IAYQR), where IPTG binding results in gene suppression. Here we engineered 46 antilacs with alternate DNA binding function (IAADR). Phenotypically, IAADR transcription factors are the inverse of wild-type I+YQR function and possess alternate DNA recognition (ADR). This collection of bespoke IAADR bind orthogonally to disparate non-natural operator DNA sequences and suppress gene expression in the presence of IPTG. This new class of IAADR gene regulators were designed modularly via the systematic pairing of nine alternate allosteric regulatory cores with six alternate DNA binding domains that interact with complementary synthetic operator DNA sequences. The 46 IAADR identified in this study are also orthogonal to the naturally occurring operator O1. Finally, a demonstration of full orthogonality was achieved via the construction of synthetic genetic toggle switches composed of two nonsynonymous unit pair operations that control two distinct fluorescent outputs. This new class of IAADR transcription factors will facilitate the expansion of the computational capacity of engineered gene circuits, via the scalable increase in the control over the number of gene outputs by way of the expansion of the number of unique transcription factors (or systems of transcription factors) that can simultaneously regulate one or more promoter(s).
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Affiliation(s)
- Ronald E. Rondon
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, Georgia 30332, United States
| | - Corey J. Wilson
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, Georgia 30332, United States
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15
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Wu J, Jiang P, Chen W, Xiong D, Huang L, Jia J, Chen Y, Jin JM, Tang SY. Design and application of a lactulose biosensor. Sci Rep 2017; 7:45994. [PMID: 28387245 PMCID: PMC5384092 DOI: 10.1038/srep45994] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 03/07/2017] [Indexed: 01/08/2023] Open
Abstract
In this study the repressor of Escherichia coli lac operon, LacI, has been engineered for altered effector specificity. A LacI saturation mutagenesis library was subjected to Fluorescence Activated Cell Sorting (FACS) dual screening. Mutant LacI-L5 was selected and it is specifically induced by lactulose but not by other disaccharides tested (lactose, epilactose, maltose, sucrose, cellobiose and melibiose). LacI-L5 has been successfully used to construct a whole-cell lactulose biosensor which was then applied in directed evolution of cellobiose 2-epimerase (C2E) for elevated lactulose production. The mutant C2E enzyme with ~32-fold enhanced expression level was selected, demonstrating the high efficiency of the lactulose biosensor. LacI-L5 can also be used as a novel regulatory tool. This work explores the potential of engineering LacI for customized molecular biosensors which can be applied in practice.
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Affiliation(s)
- Jieyuan Wu
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Peixia Jiang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Wei Chen
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Dandan Xiong
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Linglan Huang
- Beijing Key Laboratory of Plant Resources Research and Development, Beijing Technology and Business University, Beijing 100048, China
| | - Junying Jia
- Core Facility for Protein Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Yuanyuan Chen
- Core Facility for Protein Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Jian-Ming Jin
- Beijing Key Laboratory of Plant Resources Research and Development, Beijing Technology and Business University, Beijing 100048, China
| | - Shuang-Yan Tang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
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Davey J, Wilson CJ. Deconstruction of complex protein signaling switches: a roadmap toward engineering higher-order gene regulators. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2017; 9. [DOI: 10.1002/wnan.1461] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Revised: 12/13/2016] [Accepted: 01/02/2017] [Indexed: 02/06/2023]
Affiliation(s)
- James A. Davey
- Georgia Institute of Technology; School of Chemical & Biomolecular Engineering; Atlanta GA USA
| | - Corey J. Wilson
- Georgia Institute of Technology; School of Chemical & Biomolecular Engineering; Atlanta GA USA
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17
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Richards DH, Meyer S, Wilson CJ. Fourteen Ways to Reroute Cooperative Communication in the Lactose Repressor: Engineering Regulatory Proteins with Alternate Repressive Functions. ACS Synth Biol 2017; 6:6-12. [PMID: 27598336 DOI: 10.1021/acssynbio.6b00048] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The lactose repressor (LacI) is a classic genetic switch that has been used as a fundamental component in a host of synthetic genetic networks. To expand the function of LacI for use in the development of novel networks and other biotechnological applications, we engineered alternate communication in the LacI scaffold via laboratory evolution. Here we produced 14 new regulatory elements based on the LacI topology that are responsive to isopropyl β-d-1-thiogalactopyranoside (IPTG) with variation in repression strengths and ligand sensitivities-on solid media. The new variants exhibit repressive as well as antilac (i.e., inverse-repression + IPTG) functions and variations in the control of gene output upon exposure to different concentrations of IPTG. In addition, examination of this collection of variants in solution results in the controlled output of a canonical florescent reporter, demonstrating the utility of this collection of new regulatory proteins under standard conditions.
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Affiliation(s)
- David H. Richards
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Sarai Meyer
- Department of Chemical & Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
| | - Corey J. Wilson
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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18
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Sousa FL, Parente DJ, Hessman JA, Chazelle A, Teichmann SA, Swint-Kruse L. Data on publications, structural analyses, and queries used to build and utilize the AlloRep database. Data Brief 2016; 8:948-57. [PMID: 27508249 PMCID: PMC4961497 DOI: 10.1016/j.dib.2016.07.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 06/22/2016] [Accepted: 07/04/2016] [Indexed: 01/08/2023] Open
Abstract
The AlloRep database (www.AlloRep.org) (Sousa et al., 2016) [1] compiles extensive sequence, mutagenesis, and structural information for the LacI/GalR family of transcription regulators. Sequence alignments are presented for >3000 proteins in 45 paralog subfamilies and as a subsampled alignment of the whole family. Phenotypic and biochemical data on almost 6000 mutants have been compiled from an exhaustive search of the literature; citations for these data are included herein. These data include information about oligomerization state, stability, DNA binding and allosteric regulation. Protein structural data for 65 proteins are presented as easily-accessible, residue-contact networks. Finally, this article includes example queries to enable the use of the AlloRep database. See the related article, “AlloRep: a repository of sequence, structural and mutagenesis data for the LacI/GalR transcription regulators” (Sousa et al., 2016) [1].
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Affiliation(s)
- Filipa L Sousa
- Institute of Molecular Evolution, Heinrich-Heine Universität Düsseldorf, Universitätstrasse 1, 40225 Düsseldorf, Germany
| | - Daniel J Parente
- The Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Jacob A Hessman
- The Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Allen Chazelle
- The Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Sarah A Teichmann
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SD, UK; Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Liskin Swint-Kruse
- The Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, Kansas City, KS 66160, USA
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19
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Ike K, Arasawa Y, Koizumi S, Mihashi S, Kawai-Noma S, Saito K, Umeno D. Evolutionary Design of Choline-Inducible and -Repressible T7-Based Induction Systems. ACS Synth Biol 2015; 4:1352-60. [PMID: 26289535 DOI: 10.1021/acssynbio.5b00107] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
By assembly and evolutionary engineering of T7-phage-based transcriptional switches made from endogenous components of the bet operon on the Escherichia coli chromosome, genetic switches inducible by choline, a safe and inexpensive compound, were constructed. The functional plasticity of the BetI repressor was revealed by rapid and high-frequency identification of functional variants with various properties, including those with high stringency, high maximum expression level, and reversed phenotypes, from a pool of BetI mutants. The plasmid expression of BetI mutants resulted in the choline-inducible (Bet-ON) or choline-repressible (Bet-OFF) switching of genes under the pT7/betO sequence at unprecedentedly high levels, while keeping the minimal leaky expression in uninduced conditions.
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Affiliation(s)
- Kohei Ike
- Department
of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University, 1-33 Yayoi-Cyo, Inage-ku, Chiba 263-8522, Japan
| | - Yusuke Arasawa
- Department
of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University, 1-33 Yayoi-Cyo, Inage-ku, Chiba 263-8522, Japan
| | - Satoshi Koizumi
- Technology Development & Research Department, Kyowa Hakko Bio Co., Ltd., 1-6-1, Ohtemachi, Chiyoda-ku, Tokyo 100-8185, Japan
| | - Satoshi Mihashi
- Technology Development & Research Department, Kyowa Hakko Bio Co., Ltd., 1-6-1, Ohtemachi, Chiyoda-ku, Tokyo 100-8185, Japan
| | - Shigeko Kawai-Noma
- Department
of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University, 1-33 Yayoi-Cyo, Inage-ku, Chiba 263-8522, Japan
| | - Kyoichi Saito
- Department
of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University, 1-33 Yayoi-Cyo, Inage-ku, Chiba 263-8522, Japan
| | - Daisuke Umeno
- Department
of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University, 1-33 Yayoi-Cyo, Inage-ku, Chiba 263-8522, Japan
- Precursory
Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
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20
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Tobin PH, Richards DH, Callender RA, Wilson CJ. Protein engineering: a new frontier for biological therapeutics. Curr Drug Metab 2015; 15:743-56. [PMID: 25495737 DOI: 10.2174/1389200216666141208151524] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 11/27/2014] [Accepted: 12/07/2014] [Indexed: 12/14/2022]
Abstract
Protein engineering holds the potential to transform the metabolic drug landscape through the development of smart, stimulusresponsive drug systems. Protein therapeutics are a rapidly expanding segment of Food and Drug Administration approved drugs that will improve clinical outcomes over the long run. Engineering of protein therapeutics is still in its infancy, but recent general advances in protein engineering capabilities are being leveraged to yield improved control over both pharmacokinetics and pharmacodynamics. Stimulus- responsive protein therapeutics are drugs which have been designed to be metabolized under targeted conditions. Protein engineering is being utilized to develop tailored smart therapeutics with biochemical logic. This review focuses on applications of targeted drug neutralization, stimulus-responsive engineered protein prodrugs, and emerging multicomponent smart drug systems (e.g., antibody-drug conjugates, responsive engineered zymogens, prospective biochemical logic smart drug systems, drug buffers, and network medicine applications).
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Affiliation(s)
| | | | | | - Corey J Wilson
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520-8286, USA.
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21
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Ribeiro AA, Ortiz V. Local elastic constants of LacI and implications for allostery. J Mol Graph Model 2015; 57:106-13. [DOI: 10.1016/j.jmgm.2015.01.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 01/28/2015] [Accepted: 01/29/2015] [Indexed: 11/28/2022]
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22
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Ribeiro AAST, Ortiz V. Energy Propagation and Network Energetic Coupling in Proteins. J Phys Chem B 2015; 119:1835-46. [DOI: 10.1021/jp509906m] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Andre A. S. T. Ribeiro
- Department of Chemical Engineering, Columbia University, New York, New York 10027, United States
| | - Vanessa Ortiz
- Department of Chemical Engineering, Columbia University, New York, New York 10027, United States
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23
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Wilson CJ. Rational protein design: developing next‐generation biological therapeutics and nanobiotechnological tools. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2014; 7:330-41. [DOI: 10.1002/wnan.1310] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 09/02/2014] [Indexed: 01/22/2023]
Affiliation(s)
- Corey J. Wilson
- Department of Chemical and Environmental EngineeringYale UniversityNew HavenCTUSA
- Department of Molecular Biochemistry and BiophysicsYale UniversityNew HavenCTUSA
- Department of Biomedical EngineeringYale UniversityNew HavenCTUSA
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24
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Adams BL, Carter KK, Guo M, Wu HC, Tsao CY, Sintim HO, Valdes JJ, Bentley WE. Evolved Quorum sensing regulator, LsrR, for altered switching functions. ACS Synth Biol 2014; 3:210-9. [PMID: 24111753 DOI: 10.1021/sb400068z] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
In order to carry out innovative complex, multistep synthetic biology functions, members of a cell population often must communicate with one another to coordinate processes in a programmed manner. It therefore follows that native microbial communication systems are a conspicuous target for developing engineered populations and networks. Quorum sensing (QS) is a highly conserved mechanism of bacterial cell-cell communication and QS-based synthetic signal transduction pathways represent a new generation of biotechnology toolbox members. Specifically, the E. coli QS master regulator, LsrR, is uniquely positioned to actuate gene expression in response to a QS signal. In order to expand the use of LsrR in synthetic biology, two novel LsrR switches were generated through directed evolution: an "enhanced" repression and derepression eLsrR and a reversed repression/derepression function "activator" aLsrR. Protein modeling and docking studies are presented to gain insight into the QS signal binding to these two evolved proteins and their newly acquired functionality. We demonstrated the use of the aLsrR switch using a coculture system in which a QS signal, produced by one bacterial strain, is used to inhibit gene expression via aLsrR in a different strain. These first ever AI-2 controlled synthetic switches allow gene expression from the lsr promoter to be tuned simultaneously in two distinct cell populations. This work expands the tools available to create engineered microbial populations capable of carrying out complex functions necessary for the development of advanced synthetic products.
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Affiliation(s)
- Bryn L. Adams
- U.S.
Army Edgewood Chemical Biological Center, Aberdeen Proving Ground, Maryland 21010 United States
| | | | | | | | | | | | - James J. Valdes
- U.S.
Army Edgewood Chemical Biological Center, Aberdeen Proving Ground, Maryland 21010 United States
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