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Zhu Y, Gao H, Zhang J, Zhao J, Qi Q, Wang Q. De novo design of the global transcriptional factor Cra-regulated promoters enables highly sensitive glycolysis flux biosensor for dynamic metabolic control. Microb Biotechnol 2023; 16:605-617. [PMID: 36541030 PMCID: PMC9948231 DOI: 10.1111/1751-7915.14166] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 10/09/2022] [Accepted: 10/19/2022] [Indexed: 12/24/2022] Open
Abstract
Glycolytic flux is a fundamental index in microbial cell factories. A glycolytic flux biosensor that can monitor glucose metabolism efficiency is a promising strategy in rewiring metabolic flux to balance growth and biosynthesis. A key design feature of the glycolytic flux biosensors is the interaction between the global transcriptional factor Cra and its regulated promoters. However, overexpression and mutation of Cra has unpredictable effects on global metabolism in Escherichia coli. Therefore, new orthogonal biosensor design strategies should be developed to circumvent metabolic issues. In this report, the promoters in glycolytic flux biosensor were replaced with synthetic promoters of varying strengths or phage-derived promoters, and the Cra DNA-binding sites were deployed into promoters at different positions and distances to yield biosensors. The de nova biosensors that depended on Cra could sense Fructose-1,6-diphosphate (FBP) with broad dynamic ranges and low basal leakage. Then the negative-response biosensors were applied to fine-tune the target ATP synthesis gene, leading to the desired increase in pyruvate production (the highest 9.66 g/L) and cell growth. Moreover, the membrane synthesis gene plsC was also dynamically activated by the positive-response biosensor, leading to effective accumulation of lycopene in the cell membrane and a 50-fold increase in lycopene titre (100.3 mg/L) when compared with the control strain, demonstrating the effective and broader usages of our biosensors.
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Affiliation(s)
- Yuan Zhu
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Huaxiao Gao
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Jian Zhang
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Jingyu Zhao
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Qingsheng Qi
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Qian Wang
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
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2
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Vasilopoulou E, Giannakopoulou A, Kapsalis C, Michou M, Michoglou-Sergiou A, Kolisis FN, Skretas G. Second-Generation Escherichia coli SuptoxR Strains for High-Level Recombinant Membrane Protein Production. ACS Synth Biol 2022; 11:2599-2609. [PMID: 35922033 PMCID: PMC9397408 DOI: 10.1021/acssynbio.1c00598] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Escherichia coli is one of the most widely utilized hosts for recombinant protein production, including that of membrane proteins (MPs). We have recently engineered a specialized E. coli strain for enhanced recombinant MP production, termed SuptoxR. By appropriately co-expressing the effector gene rraA, SuptoxR can suppress the high toxicity, which is frequently observed during the MP-overexpression process, and, at the same time, enhance significantly the cellular accumulation of membrane-incorporated and properly folded recombinant MP. The combination of these two beneficial effects results in dramatically enhanced volumetric yields for various prokaryotic and eukaryotic MPs. Here, we engineered second-generation SuptoxR strains with further improved properties, so that they can achieve even higher levels of recombinant MP production. We searched for naturally occurring RraA variants with similar or improved MP toxicity-suppressing and production-promoting effects to that of the native E. coli RraA of the original SuptoxR strain. We found that the RraA proteins from Proteus mirabilis and Providencia stuartii can be even more potent enhancers of MP productivity than the E. coli RraA. By exploiting these two newly identified RraAs, we constructed two second-generation SuptoxR strains, termed SuptoxR2.1 and SuptoxR2.2, whose MP-production capabilities often surpass those of the original SuptoxR significantly. SuptoxR2.1 and SuptoxR2.2 are expected to become widely useful expression hosts for recombinant MP production in bacteria.
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Affiliation(s)
- Eleni Vasilopoulou
- Institute of Chemical Biology, National Hellenic Research Foundation, Athens 11635, Greece.,Department of Biochemistry and Biotechnology, University of Thessaly, Viopolis, Larisa 41500, Greece
| | - Artemis Giannakopoulou
- Institute of Chemical Biology, National Hellenic Research Foundation, Athens 11635, Greece
| | - Charalampos Kapsalis
- Institute of Chemical Biology, National Hellenic Research Foundation, Athens 11635, Greece
| | - Myrsini Michou
- Institute of Chemical Biology, National Hellenic Research Foundation, Athens 11635, Greece.,Department of Biochemistry and Biotechnology, University of Thessaly, Viopolis, Larisa 41500, Greece
| | | | - Fragiskos N Kolisis
- Laboratory of Biotechnology, School of Chemical Engineering, National Technical University of Athens, Athens 15772, Greece
| | - Georgios Skretas
- Institute of Chemical Biology, National Hellenic Research Foundation, Athens 11635, Greece
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3
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Michou M, Stergios A, Skretas G. SuptoxD2.0: A second-generation engineered Escherichia coli strain achieving further enhanced levels of recombinant membrane protein production. Biotechnol Bioeng 2020; 117:2434-2445. [PMID: 32383198 DOI: 10.1002/bit.27378] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 05/05/2020] [Accepted: 05/06/2020] [Indexed: 11/10/2022]
Abstract
The bacterium Escherichia coli is among the most popular hosts for recombinant protein production, including that of membrane proteins (MPs). We have recently generated the specialized MP-producing E. coli strain SuptoxD, which upon co-expression of the effector gene djlA, is capable of alleviating two major bottlenecks in bacterial recombinant MP production: it suppresses the toxicity that frequently accompanies the MP-overexpression process and it markedly increases the cellular accumulation of membrane incorporated and properly folded recombinant MP. Combined, these two positive effects result in dramatically enhanced volumetric yields for various recombinant MPs of both prokaryotic and eukaryotic origin. Based on the observation that djlA is found in the genomes of various pathogenic bacteria, the aim of the present work was to investigate (a) whether other naturally occurring DjlA variants can exert the MP toxicity-suppressing and production-promoting effects similarly to the E. coli DjlA and (b) if we can identify a DjlA variant whose efficiency surpasses that of the E. coli DjlA of SuptoxD. We report that a quite surprisingly broad variety of homologous DjlA proteins exert beneficial effects on recombinant MP when overexpressed in E. coli. Furthermore, we demonstrate that the Salmonella enterica DjlA is an even more potent enhancer of MP productivity compared with the E. coli DjlA of SuptoxD. Based on this, we constructed a second-generation SuptoxD strain, termed SuptoxD2.0, whose MP-production capabilities surpass significantly those of the original SuptoxD, and we anticipate that SuptoxD2.0 will become a broadly utilized expression host for recombinant MP production in bacteria.
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Affiliation(s)
- Myrsini Michou
- Institute of Chemical Biology, National Hellenic Research Foundation, Athens, Greece.,Department of Biochemistry and Biotechnology, University of Thessaly, Larisa, Greece
| | - Angelos Stergios
- Institute of Chemical Biology, National Hellenic Research Foundation, Athens, Greece.,Department of Biological Applications and Technology, University of Ioannina, Ioannina, Greece
| | - Georgios Skretas
- Institute of Chemical Biology, National Hellenic Research Foundation, Athens, Greece
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4
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Michou M, Kapsalis C, Pliotas C, Skretas G. Optimization of Recombinant Membrane Protein Production in the Engineered Escherichia coli Strains SuptoxD and SuptoxR. ACS Synth Biol 2019; 8:1631-1641. [PMID: 31243979 DOI: 10.1021/acssynbio.9b00120] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Membrane proteins (MPs) execute a wide variety of critical biological functions in all living organisms and constitute approximately half of current targets for drug discovery. As in the case of soluble proteins, the bacterium Escherichia coli has served as a very popular overexpression host for biochemical/structural studies of membrane proteins as well. Bacterial recombinant membrane protein production, however, is typically hampered by poor cellular accumulation and severe toxicity for the host, which leads to low levels of final biomass and minute volumetric yields. In previous work, we generated the engineered E. coli strains SuptoxD and SuptoxR, which upon coexpression of the effector genes djlA or rraA, respectively, can suppress the cytotoxicity caused by MP overexpression and produce enhanced MP yields. Here, we systematically looked for gene overexpression and culturing conditions that maximize the accumulation of membrane-integrated and well-folded recombinant MPs in these strains. We have found that, under optimal conditions, SuptoxD and SuptoxR achieve greatly enhanced recombinant production for a variety of MP, irrespective of their archaeal, eubacterial, or eukaryotic origin. Furthermore, we demonstrate that the use of these engineered strains enables the production of well-folded recombinant MPs of high quality and at high yields, which are suitable for functional and structural studies. We anticipate that SuptoxD and SuptoxR will become broadly utilized expression hosts for recombinant MP production in bacteria.
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Affiliation(s)
- Myrsini Michou
- Institute of Chemical Biology, National Hellenic Research Foundation, Athens 11635, Greece
- Department of Biochemistry and Biotechnology, University of Thessaly, Viopolis, Larisa 41500, Greece
| | - Charalampos Kapsalis
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews KY169ST, United Kingdom
| | - Christos Pliotas
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews KY169ST, United Kingdom
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Georgios Skretas
- Institute of Chemical Biology, National Hellenic Research Foundation, Athens 11635, Greece
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5
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Mutations in sigma 70 transcription factor improves expression of functional eukaryotic membrane proteins in Escherichia coli. Sci Rep 2019; 9:2483. [PMID: 30792443 PMCID: PMC6384906 DOI: 10.1038/s41598-019-39492-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 01/09/2019] [Indexed: 12/11/2022] Open
Abstract
Eukaryotic integral membrane proteins (IMPs) are difficult to study due to low functional expression levels. To investigate factors for efficient biogenesis of eukaryotic IMPs in the prokaryotic model organism Escherichia coli, important, e.g., for isotope-labeling for NMR, we selected for E. coli cells expressing high levels of functional G protein-coupled receptors (GPCRs) by FACS. Utilizing an E. coli strain library with all non-essential genes systematically deleted, we unexpectedly discovered upon whole-genome sequencing that the improved phenotype was not conferred by the deleted genes but by various subtle alterations in the “housekeeping” sigma 70 factor (RpoD). When analyzing effects of the rpoD mutations at the transcriptome level we found that toxic effects incurred on wild-type E. coli during receptor expression were diminished by two independent and synergistic effects: a slower but longer-lasting GPCR biosynthesis and an optimized transcriptional pattern, augmenting growth and expression at low temperature, setting the basis for further bacterial strain engineering.
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Soto-Rodríguez J, Hemmatian Z, Black J, Rolandi M, Baneyx F. Two-Channel Bioprotonic Photodetector. ACS APPLIED BIO MATERIALS 2019; 2:930-935. [DOI: 10.1021/acsabm.8b00789] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Jessica Soto-Rodríguez
- Department of Chemical Engineering, University of Washington, Box 351750, Seattle, Washington 98195, United States
| | - Zahra Hemmatian
- Department of Electrical and Computer Engineering, University of California, Santa Cruz, California 95064, United States
| | - Jennifer Black
- Department of Electrical and Computer Engineering, University of California, Santa Cruz, California 95064, United States
| | - Marco Rolandi
- Department of Electrical and Computer Engineering, University of California, Santa Cruz, California 95064, United States
| | - François Baneyx
- Department of Chemical Engineering, University of Washington, Box 351750, Seattle, Washington 98195, United States
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7
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Soto-Rodríguez J, Baneyx F. Role of the signal sequence in proteorhodopsin biogenesis in E. coli. Biotechnol Bioeng 2018; 116:912-918. [PMID: 30475397 DOI: 10.1002/bit.26878] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 10/16/2018] [Accepted: 11/21/2018] [Indexed: 12/16/2022]
Abstract
Blue-absorbing proteorhodopsin (BPR) from marine bacteria is a retinal-bound, light-activated, outwards proton transporter containing seven α-helical transmembrane segments (TMS). It is synthesized as a precursor species (pre-BPR) with a predicted N-terminal signal sequence that is cleaved to yield the mature protein. While optimizing the production of BPR in Escherichia coli to facilitate the construction of bioprotonic devices, we observed significant pre-BPR accumulation in the inner membrane and explored signal sequence requirements and export pathway. We report here that BPR does not rely on the Sec pathway for inner membrane integration, and that although it greatly enhances yields, its signal sequence is not necessary to obtain a functional product. We further show that an unprocessable version of pre-BPR obtained by mutagenesis of the signal peptidase I site exhibits all functional attributes of the wild-type protein and has the advantage of being produced at higher levels. Our results are consistent with the BPR signal sequence being recognized by the signal recognition particle (SRP; a protein that orchestrates the cotranslational biogenesis of inner membrane proteins) and serving as a beneficial "pro" domain rather than a traditional secretory peptide.
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Affiliation(s)
| | - François Baneyx
- Department of Chemical Engineering, University of Washington, Seattle, Washington
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8
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Małachowska A, Olszewski P. TECS: a toxin expression control strategy as a tool for optimization of inducible promoters. Microb Cell Fact 2018. [PMID: 29534758 PMCID: PMC5851080 DOI: 10.1186/s12934-018-0891-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Background Transcriptional control of gene expression is a widely utilized regulatory mechanism in synthetic biology, biotechnology and recombinant protein production. It is achieved by utilization of naturally occurring promoters responding to nutrients or chemicals. Despite their regulatory properties, these promoters often possess features which diminish their utility for biotechnology. High basal expression level and low induction ratio can be removed using genetic engineering techniques, although this process is often laborious and time-consuming. Results In order to facilitate optimization process for inducible promoters, we developed a simple method based on a conditional toxin expression which we abbreviate as toxin expression control strategy (TECS). In the presence of sucrose, SacB enzyme from Bacillus subtilis synthesizes levans which cause Eschericha coli cell lysis. However, in the absence of sucrose the enzyme does not affect the growth of the host. We utilized this feature to develop a two-step protocol allowing for efficient selection of inducible promoter variants. Using TECS we were able to modify the well-described pBAD promoter to decrease its leakage while maintaining high activity upon induction. Furthermore, we used the method to test transcriptional interference of lambda phage-derived sequence and optimize it for higher induction levels through random mutagenesis. Conclusions We show that TECS is an efficient tool for optimization and development of inducible promoter systems in E. coli. Our strategy is very effective in the selection of promoter variants with improved properties. Its simplicity and short hands-on time make it an attractive method to optimize existing promoters and to construct novel, engineered genetic elements which improve properties of an inducible promoter system. Electronic supplementary material The online version of this article (10.1186/s12934-018-0891-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Aleksandra Małachowska
- Department of Genetics and Biosystematics, University of Gdańsk, ul. Wita Stwosza 59, 80-308, Gdańsk, Poland
| | - Paweł Olszewski
- Department of Genetics and Biosystematics, University of Gdańsk, ul. Wita Stwosza 59, 80-308, Gdańsk, Poland.
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9
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Li R, Sakir HG, Li J, Shin HD, Du G, Chen J, Liu L. Rational molecular engineering of l-amino acid deaminase for production of α-ketoisovaleric acid from l-valine by Escherichia coli. RSC Adv 2017. [DOI: 10.1039/c6ra26972a] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The targeted modification of enzymatic efficiency can drive an increased production of desired metabolites.
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Affiliation(s)
- Ruoxi Li
- Key Laboratory of Industrial Biotechnology
- Ministry of Education
- Jiangnan University
- Wuxi 214122
- China
| | - Hossain Gazi Sakir
- Key Laboratory of Industrial Biotechnology
- Ministry of Education
- Jiangnan University
- Wuxi 214122
- China
| | - Jianghua Li
- Key Laboratory of Industrial Biotechnology
- Ministry of Education
- Jiangnan University
- Wuxi 214122
- China
| | - Hyun-dong Shin
- School of Chemical and Biomolecular Engineering
- Georgia Institute of Technology
- Atlanta 30332
- USA
| | - Guocheng Du
- Key Laboratory of Industrial Biotechnology
- Ministry of Education
- Jiangnan University
- Wuxi 214122
- China
| | - Jian Chen
- Key Laboratory of Industrial Biotechnology
- Ministry of Education
- Jiangnan University
- Wuxi 214122
- China
| | - Long Liu
- Key Laboratory of Industrial Biotechnology
- Ministry of Education
- Jiangnan University
- Wuxi 214122
- China
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10
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Soto-Rodríguez J, Hemmatian Z, Josberger EE, Rolandi M, Baneyx F. A Palladium-Binding Deltarhodopsin for Light-Activated Conversion of Protonic to Electronic Currents. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2016; 28:6581-5. [PMID: 27185384 DOI: 10.1002/adma.201600222] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 04/01/2016] [Indexed: 05/24/2023]
Abstract
Fusion of a palladium-binding peptide to an archaeal rhodopsin promotes intimate integration of the lipid-embedded membrane protein with a palladium hydride protonic contact. Devices fabricated with the palladium-binding deltarhodopsin enable light-activated conversion of protonic currents to electronic currents with on/off responses complete in seconds and a nearly tenfold increase in electrical signal relative to those made with the wild-type protein.
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Affiliation(s)
| | - Zahra Hemmatian
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, 98195, USA
- Department of Electrical Engineering, University of California, Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Erik E Josberger
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, 98195, USA
- Department of Electrical Engineering, University of Washington, Seattle, WA, 98195, USA
| | - Marco Rolandi
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, 98195, USA
- Department of Electrical Engineering, University of California, Santa Cruz, Santa Cruz, CA, 95064, USA
| | - François Baneyx
- Department of Chemical Engineering, University of Washington, Seattle, WA, 98195, USA
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11
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Engineering cells to improve protein expression. Curr Opin Struct Biol 2014; 26:32-8. [PMID: 24704806 DOI: 10.1016/j.sbi.2014.03.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 02/24/2014] [Accepted: 03/10/2014] [Indexed: 12/22/2022]
Abstract
Cellular engineering of bacteria, fungi, insect cells and mammalian cells is a promising methodology to improve recombinant protein production for structural, biochemical, and commercial applications. Increased understanding of the host organism biology has suggested engineering strategies targeting bottlenecks in transcription, translation, protein processing and secretory pathways, as well as cell growth and survival. A combination of metabolic engineering and synthetic biology has been used to improve the properties of cells for protein production, which has resulted in enhanced yields of multiple protein classes.
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12
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Bacterial-based membrane protein production. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1843:1739-49. [PMID: 24200679 DOI: 10.1016/j.bbamcr.2013.10.023] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 10/20/2013] [Accepted: 10/29/2013] [Indexed: 01/08/2023]
Abstract
Escherichia coli is by far the most widely used bacterial host for the production of membrane proteins. Usually, different strains, culture conditions and production regimes are screened for to design the optimal production process. However, these E. coli-based screening approaches often do not result in satisfactory membrane protein production yields. Recently, it has been shown that (i) E. coli strains with strongly improved membrane protein production characteristics can be engineered or selected for, (ii) many membrane proteins can be efficiently produced in E. coli-based cell-free systems, (iii) bacteria other than E. coli can be used for the efficient production of membrane proteins, and, (iv) membrane protein variants that retain functionality but are produced at higher yields than the wild-type protein can be engineered or selected for. This article is part of a Special Issue entitled: Protein trafficking and secretion in bacteria. Guest Editors: Anastassios Economou and Ross Dalbey.
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Recombinant polypeptide production in E. coli: towards a rational approach to improve the yields of functional proteins. Microb Cell Fact 2013; 12:101. [PMID: 24176192 PMCID: PMC3832250 DOI: 10.1186/1475-2859-12-101] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 10/30/2013] [Indexed: 11/16/2022] Open
Abstract
The development of complementary technologies enabled the successful production of recombinant polypeptides in bacteria and opened to biology researchers new avenues as obtaining suitable amounts of proteins necessary for their experimental work became easy, fast, and inexpensive. Nevertheless, the recombinant approach remained somehow unpredictable, since many constructs resisted to apparent production or accumulated as aggregates. Several factors and physical/chemical conditions that could improve the accumulation of native-like protein were identified. At the same time, it was acknowledged that the outcome of most of them was erratic and that almost any protein required its own specific optimized set of conditions to achieve its correct folding. The attempt to understand the critical points specific for recombinant protein production missed the goal of setting universally useful protocols, but contributed to the increase of the rate of success by proposing always new empiric combinations. Nevertheless, the results published in the recent literature allow for a better comprehension of some key mechanisms controlling protein production in E. coli and could enable the elaboration of rational methodologies for improving the quantitative and qualitative features of the produced polypeptides. This result will be achieved when the identification of the limiting step that impairs the accomplishment of the native folding for any single construct will become straightforward. This minireview will discuss how factors such as the expression rate, the folding machinery, and the secretion efficiency may impact the final protein yields.
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14
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Hochkoeppler A. Expanding the landscape of recombinant protein production in Escherichia coli. Biotechnol Lett 2013; 35:1971-81. [DOI: 10.1007/s10529-013-1396-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 06/26/2013] [Indexed: 12/11/2022]
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15
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Aboulwafa M, Saier MH. Lipid dependencies, biogenesis and cytoplasmic micellar forms of integral membrane sugar transport proteins of the bacterial phosphotransferase system. MICROBIOLOGY-SGM 2013; 159:2213-2224. [PMID: 23985145 DOI: 10.1099/mic.0.070953-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Permeases of the prokaryotic phosphoenolpyruvate-sugar phosphotransferase system (PTS) catalyse sugar transport coupled to sugar phosphorylation. The lipid composition of a membrane determines the activities of these enzyme/transporters as well as the degree of coupling of phosphorylation to transport. We have investigated mechanisms of PTS permease biogenesis and identified cytoplasmic (soluble) forms of these integral membrane proteins. We found that the catalytic activities of the soluble forms differ from those of the membrane-embedded forms. Transport via the latter is much more sensitive to lipid composition than to phosphorylation, and some of these enzymes are much more sensitive to the lipid environment than others. While the membrane-embedded PTS permeases are always dimeric, the cytoplasmic forms are micellar, either monomeric or dimeric. Scattered published evidence suggests that other integral membrane proteins also exist in cytoplasmic micellar forms. The possible functions of cytoplasmic PTS permeases in biogenesis, intracellular sugar phosphorylation and permease storage are discussed.
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Affiliation(s)
- Mohammad Aboulwafa
- Department of Microbiology and Immunology, Faculty of Pharmacy, Ain Shams University, Abbasia, Cairo, Egypt.,Department of Molecular Biology, University of California at San Diego, La Jolla, CA 92093-0116, USA
| | - Milton H Saier
- Department of Molecular Biology, University of California at San Diego, La Jolla, CA 92093-0116, USA
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16
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One-step production of α-ketoglutaric acid from glutamic acid with an engineered l-amino acid deaminase from Proteus mirabilis. J Biotechnol 2013; 164:97-104. [DOI: 10.1016/j.jbiotec.2013.01.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 01/05/2013] [Accepted: 01/09/2013] [Indexed: 11/23/2022]
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