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Development of Aspirin-Inducible Biosensors in Escherichia coli and SimCells. Appl Environ Microbiol 2019; 85:AEM.02959-18. [PMID: 30658983 PMCID: PMC6414386 DOI: 10.1128/aem.02959-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 01/09/2019] [Indexed: 01/04/2023] Open
Abstract
A simple aspirin-inducible system has been developed and characterized in Escherichia coli by employing the Psal promoter and SalR regulation system originally from Acinetobacter baylyi ADP1. Mutagenesis at the DNA binding domain (DBD) and chemical recognition domain (CRD) of the SalR protein in A. baylyi ADP1 suggests that the effector-free form, SalRr, can compete with the effector-bound form, SalRa, binding the Psal promoter and repressing gene transcription. The induction of the Psal promoter was compared in two different gene circuit designs: a simple regulation system (SRS) and positive autoregulation (PAR). Both regulatory circuits were induced in a dose-dependent manner in the presence of 0.05 to 10 µM aspirin. Overexpression of SalR in the SRS circuit reduced both baseline leakiness and the strength of the Psal promoter. The PAR circuit forms a positive feedback loop that fine-tunes the level of SalR. A mathematical simulation based on the SalRr/SalRa competitive binding model not only fit the observed experimental results in SRS and PAR circuits but also predicted the performance of a new gene circuit design for which weak expression of SalR in the SRS circuit should significantly improve induction strength. The experimental result is in good agreement with this prediction, validating the SalRr/SalRa competitive binding model. The aspirin-inducible systems were also functional in probiotic strain E. coli Nissle 1917 and SimCells produced from E. coli MC1000 ΔminD These well-characterized and modularized aspirin-inducible gene circuits would be useful biobricks for synthetic biology.IMPORTANCE An aspirin-inducible SalR/Psal regulation system, originally from Acinetobacter baylyi ADP1, has been designed for E. coli strains. SalR is a typical LysR-type transcriptional regulator (LTTR) family protein and activates the Psal promoter in the presence of aspirin or salicylate in the range of 0.05 to 10 µM. The experimental results and mathematical simulations support the competitive binding model of the SalR/Psal regulation system in which SalRr competes with SalRa to bind the Psal promoter and affect gene transcription. The competitive binding model successfully predicted that weak SalR expression would significantly improve the inducible strength of the SalR/Psal regulation system, which is confirmed by the experimental results. This provides an important mechanism model to fine-tune transcriptional regulation of the LTTR family, which is the largest family of transcriptional regulators in the prokaryotic kingdom. In addition, the SalR/Psal regulation system was also functional in probiotic strain E. coli Nissle 1917 and minicell-derived SimCells, which would be a useful biobrick for environmental and medical applications.
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Lebedev N, Yates MD, Griva I, Tender LM. Internal Redox Polarity of an Individual G. sulfurreducens Bacterial Cell Attached to an Inorganic Substrate. Chemphyschem 2018; 19:1820-1829. [PMID: 29873443 DOI: 10.1002/cphc.201800289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Indexed: 11/09/2022]
Abstract
Bacterial cell polarity is an internal asymmetric distribution of subcellular components, including proteins, lipids, and other molecules that correlates with the cell ability to sense energy and metabolite sources, chemical signals, quorum signals, toxins, and movement in the desired directions. This ability also plays central role in cell attachment to various surfaces and biofilm formation. Mechanisms and factors controlling formation of this cell internal asymmetry are not completely understood. As a step in this direction, in the present work, we develop an approach for analyzing how information about inorganic substrate can be non-genetically coded inside an individual bacterial cell. As a model system, we use G. sulfurreducens cells attached to an inorganic mineral, mica. The approach utilizes confocal Raman microscopy, Gaussian deconvolution, and Principal Component Analysis (PCA) and allows for quick label-free identification of the molecular signature of cytochrome intracellular location and the cell to substrate binding down to the level of individual bacterial cells. Our results describe a spectroscopic signature of cell adhesion and how the information about cell adhesion can be coded inside individual bacterial cells.
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Affiliation(s)
- Nikolai Lebedev
- Center for Bio/Molecular Science and Engineering, US Naval Research Laboratory, Washington, DC, 20375, USA
| | - Matthew D Yates
- Center for Bio/Molecular Science and Engineering, US Naval Research Laboratory, Washington, DC, 20375, USA
| | - Igor Griva
- Department of Mathematical Sciences and Center of Simulation and Modeling, George Mason University, Fairfax, VA, 22030, USA
| | - Leonard M Tender
- Center for Bio/Molecular Science and Engineering, US Naval Research Laboratory, Washington, DC, 20375, USA
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Jha RK, Chakraborti S, Kern TL, Fox DT, Strauss CEM. Rosetta comparative modeling for library design: Engineering alternative inducer specificity in a transcription factor. Proteins 2015; 83:1327-40. [DOI: 10.1002/prot.24828] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 04/09/2015] [Accepted: 05/02/2015] [Indexed: 11/11/2022]
Affiliation(s)
- Ramesh K. Jha
- Bioscience Division, Los Alamos National Laboratory; Los Alamos New Mexico 87545
| | - Subhendu Chakraborti
- Bioscience Division, Los Alamos National Laboratory; Los Alamos New Mexico 87545
| | - Theresa L. Kern
- Bioscience Division, Los Alamos National Laboratory; Los Alamos New Mexico 87545
| | - David T. Fox
- Bioscience Division, Los Alamos National Laboratory; Los Alamos New Mexico 87545
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Binder D, Grünberger A, Loeschcke A, Probst C, Bier C, Pietruszka J, Wiechert W, Kohlheyer D, Jaeger KE, Drepper T. Light-responsive control of bacterial gene expression: precise triggering of thelacpromoter activity using photocaged IPTG. Integr Biol (Camb) 2014; 6:755-65. [DOI: 10.1039/c4ib00027g] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
An optogenetic tool was established allowing for precise, gradual and homogeneous light-triggering oflac-based gene expression in a non-invasive fashion.
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Liang QF, Wang Q, Qi QS. [Synthetic biology and rearrangements of microbial genetic material]. YI CHUAN = HEREDITAS 2011; 33:1102-1112. [PMID: 21993285 DOI: 10.3724/sp.j.1005.2011.01102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
As an emerging discipline, synthetic biology has shown great scientific values and application prospects. Although there have been many reviews of various aspects on synthetic biology over the last years, this article, for the first time, attempted to discuss the relationship and difference between microbial genetics and synthetic biology. We summarized the recent development of synthetic biology in rearranging microbial genetic materials, including synthesis, design and reduction of genetic materials, standardization of genetic parts and modularization of genetic circuits. The relationship between synthetic biology and microbial genetic engineering was also discussed in the paper.
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Scott M, Hwa T. Bacterial growth laws and their applications. Curr Opin Biotechnol 2011; 22:559-65. [PMID: 21592775 DOI: 10.1016/j.copbio.2011.04.014] [Citation(s) in RCA: 176] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2011] [Revised: 03/24/2011] [Accepted: 04/20/2011] [Indexed: 11/28/2022]
Abstract
Quantitative empirical relationships between cell composition and growth rate played an important role in the early days of microbiology. Gradually, the focus of the field began to shift from growth physiology to the ever more elaborate molecular mechanisms of regulation employed by the organisms. Advances in systems biology and biotechnology have renewed interest in the physiology of the cell as a whole. Furthermore, gene expression is known to be intimately coupled to the growth state of the cell. Here, we review recent efforts in characterizing such couplings, particularly the quantitative phenomenological approaches exploiting bacterial 'growth laws.' These approaches point toward underlying design principles that can guide the predictive manipulation of cell behavior in the absence of molecular details.
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Affiliation(s)
- Matthew Scott
- Department of Applied Mathematics, University of Waterloo, 200 University Ave. W., Waterloo, Ontario N2L 3G1, Canada.
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Norville JE, Derda R, Gupta S, Drinkwater KA, Belcher AM, Leschziner AE, Knight TF. Introduction of customized inserts for s-treamlined assembly and optimization of BioBrick synthetic genetic circuits. J Biol Eng 2010; 4:17. [PMID: 21172029 PMCID: PMC3022552 DOI: 10.1186/1754-1611-4-17] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Accepted: 12/20/2010] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND BioBrick standard biological parts are designed to make biological systems easier to engineer (e.g. assemble, manipulate, and modify). There are over 5,000 parts available in the Registry of Standard Biological Parts that can be easily assembled into genetic circuits using a standard assembly technique. The standardization of the assembly technique has allowed for wide distribution to a large number of users -- the parts are reusable and interchangeable during the assembly process. The standard assembly process, however, has some limitations. In particular it does not allow for modification of already assembled biological circuits, addition of protein tags to pre-existing BioBrick parts, or addition of non-BioBrick parts to assemblies. RESULTS In this paper we describe a simple technique for rapid generation of synthetic biological circuits using introduction of customized inserts. We demonstrate its use in Escherichia coli (E. coli) to express green fluorescent protein (GFP) at pre-calculated relative levels and to add an N-terminal tag to GFP. The technique uses a new BioBrick part (called a BioScaffold) that can be inserted into cloning vectors and excised from them to leave a gap into which other DNA elements can be placed. The removal of the BioScaffold is performed by a Type IIB restriction enzyme (REase) that recognizes the BioScaffold but cuts into the surrounding sequences; therefore, the placement and removal of the BioScaffold allows the creation of seamless connections between arbitrary DNA sequences in cloning vectors. The BioScaffold contains a built-in red fluorescent protein (RFP) reporter; successful insertion of the BioScaffold is, thus, accompanied by gain of red fluorescence and its removal is manifested by disappearance of the red fluorescence. CONCLUSIONS The ability to perform targeted modifications of existing BioBrick circuits with BioScaffolds (1) simplifies and speeds up the iterative design-build-test process through direct reuse of existing circuits, (2) allows incorporation of sequences incompatible with BioBrick assembly into BioBrick circuits (3) removes scar sequences between standard biological parts, and (4) provides a route to adapt synthetic biology innovations to BioBrick assembly through the creation of new parts rather than new assembly standards or parts collections.
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Affiliation(s)
- Julie E Norville
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Biological Engineering Division, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Ratmir Derda
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02138, USA
| | - Saurabh Gupta
- Biological Engineering Division, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Kelly A Drinkwater
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Biological Engineering Division, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Angela M Belcher
- Biological Engineering Division, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Andres E Leschziner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Thomas F Knight
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Ginkgo BioWorks, 7 Tide St., Unit 2B, Boston, MA 02210, USA
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Bansal K, Yang K, Nistala GJ, Gennis RB, Bhalerao KD. A positive feedback-based gene circuit to increase the production of a membrane protein. J Biol Eng 2010; 4:6. [PMID: 20500847 PMCID: PMC2885990 DOI: 10.1186/1754-1611-4-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2010] [Accepted: 05/25/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Membrane proteins are an important class of proteins, playing a key role in many biological processes, and are a promising target in pharmaceutical development. However, membrane proteins are often difficult to produce in large quantities for the purpose of crystallographic or biochemical analyses. RESULTS In this paper, we demonstrate that synthetic gene circuits designed specifically to overexpress certain genes can be applied to manipulate the expression kinetics of a model membrane protein, cytochrome bd quinol oxidase in E. coli, resulting in increased expression rates. The synthetic circuit involved is an engineered, autoinducer-independent variant of the lux operon activator LuxR from V. fischeri in an autoregulatory, positive feedback configuration. CONCLUSIONS Our proof-of-concept experiments indicate a statistically significant increase in the rate of production of the bd oxidase membrane protein. Synthetic gene networks provide a feasible solution for the problem of membrane protein production.
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Affiliation(s)
- Karan Bansal
- Department of Agricultural and Biological Engineering, University of Illinois at Urbana Champaign, 1304 W, Pennsylvania Ave, Urbana, IL 61801 USA.
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Munteanu A, Constante M, Isalan M, Solé RV. Avoiding transcription factor competition at promoter level increases the chances of obtaining oscillation. BMC SYSTEMS BIOLOGY 2010; 4:66. [PMID: 20478019 PMCID: PMC2898670 DOI: 10.1186/1752-0509-4-66] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Accepted: 05/17/2010] [Indexed: 11/24/2022]
Abstract
Background The ultimate goal of synthetic biology is the conception and construction of genetic circuits that are reliable with respect to their designed function (e.g. oscillators, switches). This task remains still to be attained due to the inherent synergy of the biological building blocks and to an insufficient feedback between experiments and mathematical models. Nevertheless, the progress in these directions has been substantial. Results It has been emphasized in the literature that the architecture of a genetic oscillator must include positive (activating) and negative (inhibiting) genetic interactions in order to yield robust oscillations. Our results point out that the oscillatory capacity is not only affected by the interaction polarity but by how it is implemented at promoter level. For a chosen oscillator architecture, we show by means of numerical simulations that the existence or lack of competition between activator and inhibitor at promoter level affects the probability of producing oscillations and also leaves characteristic fingerprints on the associated period/amplitude features. Conclusions In comparison with non-competitive binding at promoters, competition drastically reduces the region of the parameters space characterized by oscillatory solutions. Moreover, while competition leads to pulse-like oscillations with long-tail distribution in period and amplitude for various parameters or noisy conditions, the non-competitive scenario shows a characteristic frequency and confined amplitude values. Our study also situates the competition mechanism in the context of existing genetic oscillators, with emphasis on the Atkinson oscillator.
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Affiliation(s)
- Andreea Munteanu
- ICREA-Complex Systems Lab, Universitat Pompeu Fabra (PRBB-GRIB), Dr Aiguader 88, 08003 Barcelona, Spain.
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Ghim CM, Kim T, Mitchell RJ, Lee SK. Synthetic biology for biofuels: Building designer microbes from the scratch. BIOTECHNOL BIOPROC E 2010. [DOI: 10.1007/s12257-009-3065-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Nistala GJ, Wu K, Rao CV, Bhalerao KD. A modular positive feedback-based gene amplifier. J Biol Eng 2010; 4:4. [PMID: 20187959 PMCID: PMC2845093 DOI: 10.1186/1754-1611-4-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2009] [Accepted: 02/26/2010] [Indexed: 11/13/2022] Open
Abstract
Background Positive feedback is a common mechanism used in the regulation of many gene circuits as it can amplify the response to inducers and also generate binary outputs and hysteresis. In the context of electrical circuit design, positive feedback is often considered in the design of amplifiers. Similar approaches, therefore, may be used for the design of amplifiers in synthetic gene circuits with applications, for example, in cell-based sensors. Results We developed a modular positive feedback circuit that can function as a genetic signal amplifier, heightening the sensitivity to inducer signals as well as increasing maximum expression levels without the need for an external cofactor. The design utilizes a constitutively active, autoinducer-independent variant of the quorum-sensing regulator LuxR. We experimentally tested the ability of the positive feedback module to separately amplify the output of a one-component tetracycline sensor and a two-component aspartate sensor. In each case, the positive feedback module amplified the response to the respective inducers, both with regards to the dynamic range and sensitivity. Conclusions The advantage of our design is that the actual feedback mechanism depends only on a single gene and does not require any other modulation. Furthermore, this circuit can amplify any transcriptional signal, not just one encoded within the circuit or tuned by an external inducer. As our design is modular, it can potentially be used as a component in the design of more complex synthetic gene circuits.
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Affiliation(s)
- Goutam J Nistala
- Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, 1304 W Pennsylvania Ave, Urbana, IL, 61801, USA
| | - Kang Wu
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 S Mathews Ave, Urbana, IL, 61801, USA
| | - Christopher V Rao
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 S Mathews Ave, Urbana, IL, 61801, USA
| | - Kaustubh D Bhalerao
- Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, 1304 W Pennsylvania Ave, Urbana, IL, 61801, USA
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Agapakis CM, Ducat DC, Boyle PM, Wintermute EH, Way JC, Silver PA. Insulation of a synthetic hydrogen metabolism circuit in bacteria. J Biol Eng 2010; 4:3. [PMID: 20184755 PMCID: PMC2847965 DOI: 10.1186/1754-1611-4-3] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Accepted: 02/25/2010] [Indexed: 02/04/2023] Open
Abstract
Background The engineering of metabolism holds tremendous promise for the production of desirable metabolites, particularly alternative fuels and other highly reduced molecules. Engineering approaches must redirect the transfer of chemical reducing equivalents, preventing these electrons from being lost to general cellular metabolism. This is especially the case for high energy electrons stored in iron-sulfur clusters within proteins, which are readily transferred when two such clusters are brought in close proximity. Iron sulfur proteins therefore require mechanisms to ensure interaction between proper partners, analogous to many signal transduction proteins. While there has been progress in the isolation of engineered metabolic pathways in recent years, the design of insulated electron metabolism circuits in vivo has not been pursued. Results Here we show that a synthetic hydrogen-producing electron transfer circuit in Escherichia coli can be insulated from existing cellular metabolism via multiple approaches, in many cases improving the function of the pathway. Our circuit is composed of heterologously expressed [Fe-Fe]-hydrogenase, ferredoxin, and pyruvate-ferredoxin oxidoreductase (PFOR), allowing the production of hydrogen gas to be coupled to the breakdown of glucose. We show that this synthetic pathway can be insulated through the deletion of competing reactions, rational engineering of protein interaction surfaces, direct protein fusion of interacting partners, and co-localization of pathway components on heterologous protein scaffolds. Conclusions Through the construction and characterization of a synthetic metabolic circuit in vivo, we demonstrate a novel system that allows for predictable engineering of an insulated electron transfer pathway. The development of this system demonstrates working principles for the optimization of engineered pathways for alternative energy production, as well as for understanding how electron transfer between proteins is controlled.
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Zeke A, Lukács M, Lim WA, Reményi A. Scaffolds: interaction platforms for cellular signalling circuits. Trends Cell Biol 2009; 19:364-74. [PMID: 19651513 DOI: 10.1016/j.tcb.2009.05.007] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2009] [Revised: 05/17/2009] [Accepted: 05/18/2009] [Indexed: 12/12/2022]
Abstract
Scaffold proteins influence cellular signalling by binding to multiple signalling enzymes, receptors or ion channels. Although normally devoid of catalytic activity, they have a big impact on controlling the flow of signalling information. By assembling signalling proteins into complexes, they play the part of signal processing hubs. As we learn more about the way signalling components are linked into natural signalling circuits, researchers are becoming interested in building non-natural signalling pathways to test our knowledge and/or to intentionally reprogram cellular behaviour. In this review, we discuss the role of scaffold proteins as efficient tools for assembling intracellular signalling complexes, both natural and artificial.
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Affiliation(s)
- András Zeke
- Department of Biochemistry, Eötvös Loránd University, Pázmány Péter sétány 1/C, H-1117 Budapest, Hungary
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