scholarly journals Akaby - cell-free protein expression system for linear templates

2021 ◽  
Author(s):  
Wakana Sato ◽  
Judee Sharon ◽  
Christopher Deich ◽  
Nathaniel Gaut ◽  
Brock Cash ◽  
...  
Keyword(s):  
Protein Expression ◽  
Expression System ◽  
Nuclease Activity ◽  
Coli Strain ◽  
Free Expression ◽  
Dna Templates ◽  
Free Protein ◽  
E Coli ◽  
Linear Dna ◽  
Simple Alternative

Cell-free protein expression is increasingly becoming popular for biotechnology, biomedical and research applications. Among cell-free systems, the most popular one is based on Escherichia coli (E. coli). Endogenous nucleases in E. coli cell-free transcription-translation (TXTL) degrade the free ends of DNA, resulting in inefficient protein expression from linear DNA templates. RecBCD is a nuclease complex that plays a major role in nuclease activity in E. coli, with the RecB subunit possessing the actual nuclease activity. We created a RecB knockout of an E. coli strain optimized for cell-free expression. We named this new strain Akaby. We demonstrated that Akaby TXTL successfully reduced linear DNA degradations, rescuing the protein expression efficiency from the linear DNA templates. The practicality of Akaby for TXTL is an efficient, simple alternative for linear template expression in cell-free reactions. We also use this work as a model protocol for modifying the TXTL source E. coli strain, enabling the creation of TXTL systems with other custom modifications.

scholarly journals Expression of Recombinant Fusion Protein of Newcastle Disease Virus from Escherichia coli Plasmid Clone C-2a by In-vitro Cell-free Protein Expression System

2020 ◽  
Vol 20 ◽  
pp. 04004
Author(s):  
Ahmad Pandu Satria Wiratama ◽  
Aris Haryanto
Keyword(s):  
Protein Expression ◽  
Newcastle Disease ◽  
Recombinant Plasmid ◽  
Expression System ◽  
Free Protein ◽  
F Protein ◽  
E Coli ◽  
Protein Expression System ◽  
Sds Page

Newcastle Disease Virus (NDV) is an infectious disease that infect many kinds of wild and domesticated birds. Infection of NDV become a massive problem for poultry industry around the world especially in Indonesia. Vaccination is an effort to prevent the infection of NDV in poultry. NDV vaccine that used in Indonesia is a conventional life vaccine from LaSota and B1 strains. These type of vaccine is 21%-23% genetically distinct with the virus that spread in the environment. The antibody protection provided by the vaccine is not effective. Therefore, vaccination with new local NDV strain is needed to prevent the NDV infection in Indonesia. The previously study research reported that the local isolate of NDV from Kulon Progo, Indonesia has been isolated. Fusion (F) protein encoding gene that has been inserted into pBT7-N-His expression p lasmid which isolated from clone C-2a of E. coli, then it was expressed by the Cell-free protein expression system. The aim of this study was to confirm whether clone C-2a of E.coli carrying a recombinant plasmid pBT7-N-His-Fusion NDV and to express a recombinant F protein of NDV in-vitro from expression plasmid by cell-free protein expression system. This work started by detection of recombinant plasmid pBT7-N-His-Fusion NDV by DNA plasmid extraction followed by agarose gel electrophoresis. The recombinant F protein was in-vitro expressed by cell-free protein expression kit. The expressed F protein of NDV then was visualized by SDS-PAGE and Westernblott to analyse the expression of NDV recombinant F protein. It confirmed that clone C-2a of E. coli contained plasmid pBT7-N-His (4.001 bp) inserted by recombinant F protein of NDV gene (642 bp). The visualisation of expressed recombinant F protein by SDS-PAGE and Westernblott showed the NDV recombinant F protein was a specific protein fragment with molecular weight of 25,6 kDa..

scholarly journals A Methylation-Directed, Synthetic Pap Switch Based on Self-Complementary Regulatory DNA in an All-E. Coli Cell-Free Expression System

2020 ◽  
Author(s):  
Emanuel Worst ◽  
oemer Kurt ◽  
Marc Finkler ◽  
Marc Schenkelberger ◽  
Vincent Noireaux ◽  
...  
Keyword(s):  
Expression System ◽  
Regulatory Region ◽  
Phase Variation ◽  
Coli Strain ◽  
Coli Cell ◽  
Free Expression ◽  
E Coli ◽  
Regulatory Dna ◽  
Cell Free Expression System

<p>Pyelonephritis-associated pili (pap) enable migration of the uropathogenic Escherichia coli strain (UPEC) through the urinary tract. UPEC can switch between a stable 'ON phase' where the corresponding pap genes are expressed and a stable 'OFF phase' where their transcription is repressed. Hereditary, alternate DNA methylation of only two GATC motives within the regulatory region stabilizes the respective phase over many generations. The underlying molecular mechanism is only partly understood. Previous investigations suggest that in vivo phase-variation stability results from cooperative action of the transcriptional regulators Lrp and PapI. Here, we use an E. coli cell-free expression system to study the function of pap regulatory region based on a specially designed, synthetic construct flanked by two reporter genes encoding fluorescent proteins for simple readout. Based on our observations we suggest that Lrp and the conformation of the self-complementary regulatory DNA play a strong role in the regulation of phase-variation. Our work not only contributes to better understand the phase variation mechanism, but it represents a successful start for engineering stable, hereditary and strong expression control based on methylation.</p>

scholarly journals A Methylation-Directed, Synthetic Pap Switch Based on Self-Complementary Regulatory DNA in an All-E. Coli Cell-Free Expression System

2020 ◽  
Author(s):  
Emanuel Worst ◽  
oemer Kurt ◽  
Marc Finkler ◽  
Marc Schenkelberger ◽  
Vincent Noireaux ◽  
...  
Keyword(s):  
Expression System ◽  
Regulatory Region ◽  
Phase Variation ◽  
Coli Strain ◽  
Coli Cell ◽  
Free Expression ◽  
E Coli ◽  
Regulatory Dna ◽  
Cell Free Expression System

<p>Pyelonephritis-associated pili (pap) enable migration of the uropathogenic Escherichia coli strain (UPEC) through the urinary tract. UPEC can switch between a stable 'ON phase' where the corresponding pap genes are expressed and a stable 'OFF phase' where their transcription is repressed. Hereditary, alternate DNA methylation of only two GATC motives within the regulatory region stabilizes the respective phase over many generations. The underlying molecular mechanism is only partly understood. Previous investigations suggest that in vivo phase-variation stability results from cooperative action of the transcriptional regulators Lrp and PapI. Here, we use an E. coli cell-free expression system to study the function of pap regulatory region based on a specially designed, synthetic construct flanked by two reporter genes encoding fluorescent proteins for simple readout. Based on our observations we suggest that Lrp and the conformation of the self-complementary regulatory DNA play a strong role in the regulation of phase-variation. Our work not only contributes to better understand the phase variation mechanism, but it represents a successful start for engineering stable, hereditary and strong expression control based on methylation.</p>

scholarly journals In silico Design of Linear DNA for Robust Cell-Free Gene Expression

2021 ◽  
Vol 9 ◽  
Author(s):  
Xinjie Chen ◽  
Yuan Lu
Keyword(s):  
Gene Expression ◽  
Protein Expression ◽  
High Throughput Screening ◽  
Expression System ◽  
Dna Templates ◽  
Linear Dna ◽  
Low Protein ◽  
Cell Extracts ◽  
Free Gene ◽  
Expression Templates

Cell-free gene expression systems with linear DNA expression templates (LDETs) have been widely applied in artificial cells, biochips, and high-throughput screening. However, due to the degradation caused by native nucleases in cell extracts, the transcription with linear DNA templates is weak, thereby resulting in low protein expression level, which greatly limits the development of cell-free systems using linear DNA templates. In this study, the protective sequences for stabilizing linear DNA and the transcribed mRNAs were rationally designed according to nucleases’ action mechanism, whose effectiveness was evaluated through computer simulation and cell-free gene expression. The cell-free experiment results indicated that, with the combined protection of designed sequence and GamS protein, the protein expression of LDET-based cell-free systems could reach the same level as plasmid-based cell-free systems. This study would potentially promote the development of the LDET-based cell-free gene expression system for broader applications.

Protecting Linear DNA Templates in Cell-Free Expression Systems from Diverse Bacteria

2020 ◽  
Vol 9 (10) ◽  
pp. 2851-2855
Author(s):  
Sung Sun Yim ◽  
Nathan I. Johns ◽  
Vincent Noireaux ◽  
Harris H. Wang
Keyword(s):  
Free Expression ◽  
Expression Systems ◽  
Dna Templates ◽  
Linear Dna

Effect of supplementing Moringa oleifera essential oils on milk quality and fatty acid profile in dairy sheep

2019 ◽  
Author(s):  
N. Hemamalini ◽  
S. Ezhilmathi ◽  
A. Angela Mercy
Keyword(s):  
Recombinant Protein ◽  
Protein Expression ◽  
Cell Biology ◽  
Genetic Manipulation ◽  
Recombinant Protein Expression ◽  
Coli Strain ◽  
Expression Vectors ◽  
Functional Domain ◽  
Post Translational Modifications ◽  
E Coli

Escherichia coli is the most extensively used organism in recombinant protein production. It has several advantages including a very short life cycle, ease of genetic manipulation and the well-known cell biology etc. which makes E. coli as the perfect host for recombinant protein expression. Despite many advantages, E. coli also have few disadvantages such as coupled transcription and translation and lack of eukaryotic post-translational modifications. These challenges can be overcome by adopting several strategies such as, using different E. coli expression vectors, changing the gene sequence without altering the functional domain, modified E. coli strain usage, changing the culture parameters and co-expression with a molecular chaperone. In this review, we present the level of strategies used to enhance the recombinant protein expression and its stability in E. coli.

scholarly journals IMP dehydrogenase from Pneumocystis carinii as a potential drug target.

1997 ◽  
Vol 41 (1) ◽  
pp. 40-48 ◽  
Author(s):  
M J O'Gara ◽  
C H Lee ◽  
G A Weinberg ◽  
J M Nott ◽  
S F Queener
Keyword(s):  
Mycophenolic Acid ◽  
Expression System ◽  
Pneumocystis Carinii ◽  
Specific Inhibitor ◽  
Coli Strain ◽  
Northern Hybridization ◽  
Imp Dehydrogenase ◽  
E Coli ◽  
The Mean

Mycophenolic acid, a specific inhibitor of IMP dehydrogenase (IMPDH; EC 1.1.1.205), is a potent inhibitor of Pneumocystis carinii growth in culture, suggesting that IMPDH may be a sensitive target for chemotherapy in this organism. The IMPDH gene was cloned as a first step to characterizing the enzyme and developing selective inhibitors. A 1.3-kb fragment containing a portion of the P. carinii IMPDH gene was amplified by PCR with two degenerate oligonucleotides based on conserved sequences in IMPDH from humans and four different microorganisms. Northern hybridization analysis showed the P. carinii IMPDH mRNA to be approximately 1.6 kb. The entire cDNA encoding P. carinii IMPDH was isolated and cloned. The deduced amino acid sequence of P. carinii IMPDH shared homology with bacterial (31 to 38%), protozoal (48 to 59%), mammalian (60 to 62%), and fungal (62%) IMPDH enzymes. The IMPDH cDNA was expressed by using a T7 expression system in an IMPDH-deficient strain of Escherichia coli (strain S phi 1101). E. coli S phi 1101 cells containing the P. carinii IMPDH gene were able to grow on medium lacking guanine, implying that the protein expressed in vivo was functional. Extracts of these E. coli cells contained IMPDH activity that had an apparent Km for IMP of 21.7 +/- 0.3 microM and an apparent Km for NAD of 314 +/- 84 microM (mean +/- standard error of the mean; n = 3), and the activity was inhibited by mycophenolic acid (50% inhibitory concentration, 24 microM; n = 2).

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