Escherichia colias an expression system for K+transport systems from plants

2001 ◽  
Vol 281 (3) ◽  
pp. C733-C739 ◽  
Author(s):  
Nobuyuki Uozumi
Keyword(s):  
Membrane Proteins ◽  
Expression System ◽  
Functional Expression ◽  
Host Cells ◽  
Transport Systems ◽  
Membrane Structures ◽  
E Coli ◽  
Escherichia Coli Expression ◽  
Experimental Findings ◽  
And Function

The value of the Escherichia coli expression system has long been established because of its effectiveness in characterizing the structure and function of exogenously expressed proteins. When eukaryotic membrane proteins are functionally expressed in E. coli, this organism can serve as an alternative to eukaryotic host cells. A few examples have been reported of functional expression of animal and plant membrane proteins in E. coli. This mini-review describes the following findings: 1) homologous K+transporters exist in prokaryotic cells and in eukaryotic cells; 2) plant K+transporters can functionally complement mutant K+transporter genes in E. coli; and 3) membrane structures of plant K+transporters can be elucidated in an E. colisystem. These experimental findings suggest the possibility of utilizing the E. coli bacterium as an expression system for other eukaryotic membrane transport proteins.

scholarly journals Functional expression of the eukaryotic proton pump rhodopsin OmR2 in Escherichia coli and its photochemical characterization

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Masuzu Kikuchi ◽  
Keiichi Kojima ◽  
Shin Nakao ◽  
Susumu Yoshizawa ◽  
Shiho Kawanishi ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Proton Pump ◽  
Expression System ◽  
Spectroscopic Characterization ◽  
Functional Expression ◽  
Proton Pumping ◽  
E Coli ◽  
Oxyrrhis Marina ◽  
Domains Of Life

AbstractMicrobial rhodopsins are photoswitchable seven-transmembrane proteins that are widely distributed in three domains of life, archaea, bacteria and eukarya. Rhodopsins allow the transport of protons outwardly across the membrane and are indispensable for light-energy conversion in microorganisms. Archaeal and bacterial proton pump rhodopsins have been characterized using an Escherichia coli expression system because that enables the rapid production of large amounts of recombinant proteins, whereas no success has been reported for eukaryotic rhodopsins. Here, we report a phylogenetically distinct eukaryotic rhodopsin from the dinoflagellate Oxyrrhis marina (O. marina rhodopsin-2, OmR2) that can be expressed in E. coli cells. E. coli cells harboring the OmR2 gene showed an outward proton-pumping activity, indicating its functional expression. Spectroscopic characterization of the purified OmR2 protein revealed several features as follows: (1) an absorption maximum at 533 nm with all-trans retinal chromophore, (2) the possession of the deprotonated counterion (pKa = 3.0) of the protonated Schiff base and (3) a rapid photocycle through several distinct photointermediates. Those features are similar to those of known eukaryotic proton pump rhodopsins. Our successful characterization of OmR2 expressed in E. coli cells could build a basis for understanding and utilizing eukaryotic rhodopsins.

scholarly journals Functional Studies of [FeFe] Hydrogenase Maturation in an Escherichia coli Biosynthetic System

2006 ◽  
Vol 188 (6) ◽  
pp. 2163-2172 ◽  
Author(s):  
Paul W. King ◽  
Matthew C. Posewitz ◽  
Maria L. Ghirardi ◽  
Michael Seibert
Keyword(s):  
Escherichia Coli ◽  
Catalytic Domain ◽  
Expression System ◽  
Iron Sulfur Cluster ◽  
Sulfur Cluster ◽  
E Coli ◽  
Functional Studies ◽  
Hydrogenase Maturation ◽  
Iron Sulfur ◽  
And Function

ABSTRACT Maturation of [FeFe] hydrogenases requires the biosynthesis and insertion of the catalytic iron-sulfur cluster, the H cluster. Two radical S-adenosylmethionine (SAM) proteins proposed to function in H cluster biosynthesis, HydEF and HydG, were recently identified in the hydEF-1 mutant of the green alga Chlamydomonas reinhardtii (M. C. Posewitz, P. W. King, S. L. Smolinski, L. Zhang, M. Seibert, and M. L. Ghirardi, J. Biol. Chem. 279:25711-25720, 2004). Previous efforts to study [FeFe] hydrogenase maturation in Escherichia coli by coexpression of C. reinhardtii HydEF and HydG and the HydA1 [FeFe] hydrogenase were hindered by instability of the hydEF and hydG expression clones. A more stable [FeFe] hydrogenase expression system has been achieved in E. coli by cloning and coexpression of hydE, hydF, and hydG from the bacterium Clostridium acetobutylicum. Coexpression of the C. acetobutylicum maturation proteins with various algal and bacterial [FeFe] hydrogenases in E. coli resulted in purified enzymes with specific activities that were similar to those of the enzymes purified from native sources. In the case of structurally complex [FeFe] hydrogenases, maturation of the catalytic sites could occur in the absence of an accessory iron-sulfur cluster domain. Initial investigations of the structure and function of the maturation proteins HydE, HydF, and HydG showed that the highly conserved radical-SAM domains of both HydE and HydG and the GTPase domain of HydF were essential for achieving biosynthesis of active [FeFe] hydrogenases. Together, these results demonstrate that the catalytic domain and a functionally complete set of Hyd maturation proteins are fundamental to achieving biosynthesis of catalytic [FeFe] hydrogenases.

STEM-18. STROMAL EXTRACELLULAR VESICLES DRIVE GLIOMA STEM CELL REPROGRAMMING

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi24-vi25
Author(s):  
Lata Adnani ◽  
Brian Meehan ◽  
Jordan Kassouf ◽  
Cristiana Spinelli ◽  
Nadim Tawil ◽  
...  
Keyword(s):  
Molecular Subtype ◽  
Extracellular Vesicle ◽  
Host Cells ◽  
Tumour Mass ◽  
Membrane Structures ◽  
And Function ◽  
Rate Limiting ◽  
The Brain

Abstract Glioblastoma multiforme (GBM) represents the most frequent and lethal form of brain tumors originating from glioma stem cells (GSCs). GBM remains lethal because the rate limiting patho-mechanisms remain poorly understood. In this regard, few limitations involve the diversity 'between' cellular states and the molecular/cellular complexity 'within' the tumour mass. Using cell based- and mouse- models, we explored extracellular vesicle (EV) mediated interactions between cancer and stromal cells impacting phenotypes of GSCs as a function of their molecular subtype. EVs are spherical membrane structures that cells release to expel different molecular cargo (lipids, proteins, RNA, DNA), which can be transported across a distance in the brain and taken up by various ‘recipient’ cells resulting in reprogramming of the recipient cell's content and function. In vivo, GSCs altered their pattern of NOTCH signalling and molecular phenotype as a function of proximity to non-transformed host cells in the brain. In vitro stromal EVs altered GSC sphere forming capacity, proteome and expression of mesenchymal markers. Thus, EV mediated tumour-stromal interactions could represent a biological switch and a novel targeting point in the biology of GBM.

scholarly journals Functional Expression and One-Step Protein Purification of Manganese Peroxidase 1 (rMnP1) from Phanerochaete chrysosporium Using the E. coli-Expression System

2020 ◽  
Vol 21 (2) ◽  
pp. 416
Author(s):  
Angel De La Cruz Pech-Canul ◽  
Javier Carrillo-Campos ◽  
María de Lourdes Ballinas-Casarrubias ◽  
Rosa Lidia Solis-Oviedo ◽  
Selena Karina Hernández-Rascón ◽  
...  
Keyword(s):  
Fusion Protein ◽  
Protein Purification ◽  
Phanerochaete Chrysosporium ◽  
Manganese Peroxidase ◽  
Expression System ◽  
White Rot Fungi ◽  
Functional Expression ◽  
White Rot ◽  
E Coli ◽  
One Step

Manganese peroxidases (MnP) from the white-rot fungi Phanerochaete chrysosporium catalyse the oxidation of Mn2+ to Mn3+, a strong oxidizer able to oxidize a wide variety of organic compounds. Different approaches have been used to unravel the enzymatic properties and potential applications of MnP. However, these efforts have been hampered by the limited production of native MnP by fungi. Heterologous expression of MnP has been achieved in both eukaryotic and prokaryotic expression systems, although with limited production and many disadvantages in the process. Here we described a novel molecular approach for the expression and purification of manganese peroxidase isoform 1 (MnP1) from P. chrysosporium using an E. coli-expression system. The proposed strategy involved the codon optimization and chemical synthesis of the MnP1 gene for optimised expression in the E. coli T7 shuffle host. Recombinant MnP1 (rMnP1) was expressed as a fusion protein, which was recovered from solubilised inclusion bodies. rMnP1 was purified from the fusion protein using intein-based protein purification techniques and a one-step affinity chromatography. The designated strategy allowed production of an active enzyme able to oxidize guaiacol or Mn2+.

scholarly journals S-Adenosylmethionine Transport in Rickettsia prowazekii

2003 ◽  
Vol 185 (10) ◽  
pp. 3031-3035 ◽  
Author(s):  
Aimee M. Tucker ◽  
Herbert H. Winkler ◽  
Lonnie O. Driskell ◽  
David O. Wood
Keyword(s):  
Evolutionary Relationship ◽  
Host Cells ◽  
Transport Systems ◽  
Rickettsia Prowazekii ◽  
Gene Encoding ◽  
E Coli ◽  
Obligate Intracellular ◽  
Gene Coding ◽  
Epidemic Typhus ◽  
Methionine Transport

ABSTRACT Rickettsia prowazekii, the causative agent of epidemic typhus, is an obligate, intracellular, parasitic bacterium that grows within the cytoplasm of eucaryotic host cells. Rickettsiae exploit this intracellular environment by using transport systems for the compounds available in the host cell's cytoplasm. Analysis of the R. prowazekii Madrid E genome sequence revealed the presence of a mutation in the rickettsial metK gene, the gene encoding the enzyme responsible for the synthesis of S-adenosylmethionine (AdoMet). Since AdoMet is required for rickettsial processes, the apparent inability of this strain to synthesize AdoMet suggested the presence of a rickettsial AdoMet transporter. We have confirmed the presence of an AdoMet transporter in the rickettsiae which, to our knowledge, is the first bacterial AdoMet transporter identified. The influx of AdoMet into rickettsiae was a saturable process with a KT of 2.3 μM. Transport was inhibited by S-adenosylethionine and S-adenosylhomocysteine but not by sinfungin or methionine. Transport was also inhibited by 2,4-dinitrophenol, suggesting an energy-linked transport mechanism, and by N-ethylmaleimide. AdoMet transporters with similar properties were also identified in the Breinl strain of R. prowazekii and in Rickettsia typhi. By screening Escherichia coli clone banks for AdoMet transport, the R. prowazekii gene coding for a transporter, RP076 (sam), was identified. AdoMet transport in E. coli containing the R. prowazekii sam gene exhibited kinetics similar to that seen in rickettsiae. The existence of a rickettsial transporter for AdoMet raises intriguing questions concerning the evolutionary relationship between the synthesis and transport of this essential metabolite.

scholarly journals Regulatable Arabinose-Inducible Gene Expression System with Consistent Control in All Cells of a Culture

2000 ◽  
Vol 182 (24) ◽  
pp. 7029-7034 ◽  
Author(s):  
Artem Khlebnikov ◽  
Øystein Risa ◽  
Tove Skaug ◽  
Trent A. Carrier ◽  
J. D. Keasling
Keyword(s):  
Gene Expression ◽  
Expression System ◽  
High Capacity ◽  
Inducible Promoter ◽  
Transport Systems ◽  
Specific Expression ◽  
Homogeneous Population ◽  
E Coli ◽  
Transport Control ◽  
Inducible Gene

ABSTRACT The arabinose-inducible promoter PBAD is subject to all-or-none induction, in which intermediate concentrations of arabinose give rise to subpopulations of cells that are fully induced and uninduced. To construct a host-vector expression system with regulatable control in a homogeneous population of cells, thearaE gene of Escherichia coli was cloned into an RSF1010-derived plasmid under control of the isopropyl-β-d-thiogalactopyranoside-induciblePtac and Ptaclac promoters. This gene encodes the low-affinity, high-capacity arabinose transport protein and is controlled natively by an arabinose-inducible promoter. To detect the effect of arabinose-independentaraE expression on population homogeneity and cell-specific expression, the gfpuv gene was placed under control of the arabinose-inducible araBAD promoter (PBAD ) on the pMB1-derived plasmid pBAD24. The transporter and reporter plasmids were transformed into E. coli strains with native arabinose transport systems and strains deficient in one or both of the arabinose transport systems (araE and/or araFGH). The effects of the arabinose concentration and arabinose-independent transport control on population homogeneity were investigated in these strains using flow cytometry. The araE, and araE araFGHmutant strains harboring the transporter and reporter plasmids were uniformly induced across the population at all inducer concentrations, and the level of gene expression in individual cells varied with arabinose concentration. In contrast, the parent strain, which expressed the native araE and araFGH genes and harbored the transporter and reporter plasmids, exhibited all-or-none behavior. This work demonstrates the importance of including a transport gene that is controlled independently of the inducer to achieve regulatable and consistent induction in all cells of the culture.

scholarly journals Mutagenesis and Functional Reconstitution of Chlamydial Major Outer Membrane Proteins: VS4 Domains Are Not Required for Pore Formation but Modify Channel Function

2001 ◽  
Vol 69 (3) ◽  
pp. 1671-1678 ◽  
Author(s):  
E. S. Hughes ◽  
K. M. Shaw ◽  
R. H. Ashley
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Single Channel ◽  
Outer Membrane Proteins ◽  
Host Cells ◽  
Chimeric Proteins ◽  
Functional Differences ◽  
And Function ◽  
Bacterial Porins ◽  
Medical Interest

ABSTRACT Chlamidial organisms are obligate intracellular pathogens containing highly antigenic porin-like major outer membrane proteins (MOMPs). MOMP epitopes are of substantial medical interest, and they cluster within four relatively short variable (VS) domains. If MOMPs adopt a β-barrel fold, like bacterial porins, the VS domains may form extramembranous loops and the conserved regions of the protein may correspond to predicted membrane-located β-strands. However, molecular studies on native MOMPs have been hampered by the need to culture chlamydiae in eukaryotic host cells and purification and reconstitution remain problematic. In addition, the organisms are difficult to manipulate genetically, and it has also been difficult to functionally reconstitute recombinant MOMPs. To help overcome these problems and improve our understanding of MOMP structure and function, we cloned and expressed C. trachomatis and C. psittaci MOMPs and functionally reconstituted them at the single-channel level. We measured significant functional differences between the two proteins, and by removing and exchanging VS4, we tested the hypothesis that the largest variable domain forms an extramembranous loop that contributes to these differences. Proteins in which VS4 was deleted continued to form functional ion channels, consistent with the idea that the domain forms an extramembranous protein loop and incompatible with models in which it contributes to predicted membrane-located β-strands. Additionally, the properties of the chimeric proteins strongly suggested that the VS4 domain interacts closely with other regions of the protein to form the channel entrance or vestibule. Our approach can be used to probe structure-function relationships in chlamydial MOMPs and may have implications for the generation of effective antichlamydial vaccines.

scholarly journals Distribution, Functional Expression, and Genetic Organization of Cif, a Phage-Encoded Type III-Secreted Effector from Enteropathogenic and Enterohemorrhagic Escherichia coli

2007 ◽  
Vol 190 (1) ◽  
pp. 275-285 ◽  
Author(s):  
Estelle Loukiadis ◽  
Rika Nobe ◽  
Sylvia Herold ◽  
Clara Tramuta ◽  
Yoshitoshi Ogura ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Functional Expression ◽  
Effector Proteins ◽  
Enterohemorrhagic Escherichia Coli ◽  
Host Cells ◽  
E Coli ◽  
Type Iii ◽  
Related Phenotype ◽  
Enterocyte Effacement ◽  
Lambdoid Prophage

ABSTRACT Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) inject effector proteins into host cells via a type III secretion system encoded by the locus of enterocyte effacement (LEE). One of these effectors is Cif, encoded outside the LEE by a lambdoid prophage. In this study, we demonstrated that the Cif-encoding prophage of EPEC strain E22 is inducible and produces infectious phage particles. We investigated the distribution and functional expression of Cif in 5,049 E. coli strains of human, animal, and environmental origins. A total of 115 E. coli isolates from diverse origins and geographic locations carried cif. The presence of cif was tightly associated with the LEE, since all the cif-positive isolates were positive for the LEE. These results suggested that the Cif-encoding prophages have been widely disseminated within the natural population of E. coli but positively selected within the population of LEE-positive strains. Nonetheless, 66% of cif-positive E. coli strains did not induce a typical Cif-related phenotype in eukaryotic cells due to frameshift mutations or insertion of an IS element in the cif gene. The passenger region of the prophages carrying cif was highly variable and showed various combinations of IS elements and genes coding for other effectors such as nleB, nleC, nleH, nleG, espJ, and nleA/espI (some of which were also truncated). This diversity and the presence of nonfunctional effectors should be taken into account to assess EPEC and EHEC pathogenicity and tropism.

scholarly journals Expression and characterisation of the ryegrass mottle virus non-structural proteins

2010 ◽  
Vol 64 (5-6) ◽  
pp. 215-222
Author(s):  
Ina Baļķe ◽  
Gunta Resēviča ◽  
Dace Skrastiņa ◽  
Andris Zeltiņš
Keyword(s):  
Amino Acid ◽  
Expression System ◽  
Protein Structures ◽  
Amino Acid Sequences ◽  
Host Cells ◽  
Structural Proteins ◽  
Mottle Virus ◽  
Expression Vectors ◽  
Structural Protein ◽  
E Coli

Expression and characterisation of the ryegrass mottle virus non-structural proteins The Ryegrass mottle virus (RGMoV) single-stranded RNA genome is organised into four open reading frames (ORF) which encode several proteins: ORF1 encodes protein P1, ORF2a contains the membrane-associated 3C-like serine protease, genome-linked protein VPg and a P16 protein gene. ORF2b encodes replicase RdRP and the only structural protein, coat protein, is synthesised from ORF3. To obtain the non-structural proteins in preparative quantities and to characterise them, the corresponding RGMoV gene cDNAs were cloned in pET- and pColdI-derived expression vectors and overexpressed in several E. coli host cells. For protease and RdRP, the best expression system containing pColdI vector and E. coli WK6 strain was determined. VPg and P16 proteins were obtained from the pET- or pACYC- vectors and E. coli BL21 (DE3) host cells and purified using Ni-Sepharose affinity chromatography. Attempts to crystallize VPg and P16 were unsuccessful, possibly due to non-structured amino acid sequences in both protein structures. Methods based on bioinformatic analysis indicated that the entire VPg domain and the C-terminal part of the P16 contain unstructured amino acid stretches, which possibly prevented the formation of crystals.

Thermoinducible expression system for producing recombinant proteins in Escherichia coli: advances and insights

2021 ◽  
Author(s):  
Sara Restrepo-Pineda ◽  
Néstor O. Pérez ◽  
Norma A Valdez-Cruz ◽  
Mauricio A Trujillo-Roldán
Keyword(s):  
Escherichia Coli ◽  
Expression System ◽  
Regulatory Elements ◽  
Host Cells ◽  
Chemical Inducers ◽  
E Coli ◽  
Current Scenario ◽  
Industrial Level ◽  
The Relationship ◽  
Potential Use

ABSTRACT Recombinant protein (RP) production from Escherichia coli has been extensively studied to find strategies for increasing product yields. The thermoinducible expression system is commonly employed at the industrial level to produce various RPs, which avoids the addition of chemical inducers, thus minimizing contamination risks. Multiple aspects of the molecular origin and biotechnological uses of its regulatory elements (pL/pR promoters and cI857 thermolabile repressor) derived from bacteriophage λ provide knowledge to improve the bioprocesses using this system. Here, we discuss the main aspects of the potential use of the λpL/pR-cI857 thermoinducible system for RP production in E. coli, focusing on the approaches of investigations that have contributed to the advancement of this expression system. Metabolic and physiological changes that occur in the host cells caused by heat stress and RP overproduction are also described. Therefore, the current scenario and the future applications of systems that use heat to induce RP production are discussed to understand the relationship between the activation of the bacterial heat shock response, RP accumulation and its possible aggregation to form inclusion bodies.

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