The Expression and Purification of Recombinant Mouse Ameloblastin in E. coli.
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ABSTRACT:
SUBMITTER: Su J
PROVIDER: S-EPMC8011534 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundRecombinant DNA technologies have played a pivotal role in the elucidation of structure-function relationships in hemoglobin (Hb) and other globin proteins. Here we describe the development of a plasmid expression system to synthesize recombinant Hbs in Escherichia coli, and we describe a protocol for expressing Hbs with low intrinsic solubilities. Since the α- and β-chain Hbs of different species span a broad range of solubilities, experimental protocols that have been optimized for expressing recombinant human HbA may often prove unsuitable for the recombinant expression of wildtype and mutant Hbs of other species.Methodology/principal findingsAs a test case for our expression system, we produced recombinant Hbs of the deer mouse (Peromyscus maniculatus), a species that has been the subject of research on mechanisms of Hb adaptation to hypoxia. By experimentally assessing the combined effects of induction temperature, induction time and E. coli expression strain on the solubility of recombinant deer mouse Hbs, we identified combinations of expression conditions that greatly enhanced the yield of recombinant protein and which also increased the efficiency of post-translational modifications.Conclusion/significanceOur protocol should prove useful for the experimental study of recombinant Hbs in many non-human animals. One of the chief advantages of our protocol is that we can express soluble recombinant Hb without co-expressing molecular chaperones, and without the need for additional reconstitution or heme-incorporation steps. Moreover, our plasmid construct contains a combination of unique restriction sites that allows us to produce recombinant Hbs with different α- and β-chain subunit combinations by means of cassette mutagenesis.
| S-EPMC3098879 | biostudies-literature
Project description:Dermatopontin (DPT) is an extracellular matrix (ECM) protein with diversified pharmaceutical applications. It plays important role in cell adhesion/migration, angiogenesis and ECM maintenance. The recombinant production of this protein will enable further exploration of its multifaceted functions. In this study, DPT protein has been expressed in Escherichia coli (E.coli) aiming at cost effective recombinant production. The E.coli GJ1158 expression system was transformed with constructed recombinant vector (pRSETA-DPT) and protein was expressed as inclusion bodies on induction with NaCl. The inclusion bodies were solubilised in urea and renaturation of protein was done by on-column refolding procedure in Nickel activated Sepharose column. The refolded Histidine-tagged DPT protein was purified and eluted from column using imidazole and its purity was confirmed by analytical techniques. The biological activity of the protein was confirmed by collagen fibril assay, wound healing assay and Chorioallantoic Membrane (CAM) angiogenesis assay on comparison with standard DPT. The purified DPT was found to enhance the collagen fibrillogenesis process and improved the migration of human endothelial cells. About 73% enhanced wound closure was observed in purified DPT treated endothelial cells as compared to control. The purified DPT also could induce neovascularisation in the CAM model. At this stage, scaling up the production process for DPT with appropriate purity and reproducibility will have a promising commercial edge.
| S-EPMC7703894 | biostudies-literature
Project description:Cullin-2 (CUL2) based cullin-RING ligases (CRL2s) comprise a family of ubiquitin E3 ligases that exist only in multi-cellular organisms and are crucial for cellular processes such as embryogenesis and viral pathogenesis. CUL2 is the scaffold protein that binds one of the interchangeable substrate receptor modules, which consists of adaptor proteins and the substrate receptor protein. The VHL protein is a substrate receptor known to target hypoxia-inducible factor α (HIF1α) for ubiquitination and degradation. Because of its critical role in the ubiquitination of important cellular factors such as HIF1α, CRL2s have been investigated for their biological functions and the development of novel therapeutics against diseases. Given the importance of CRL2s in biological and biomedical research, methods that efficiently produce functional CUL2 proteins will greatly facilitate studies on the mechanism and regulation of CRL2s. Here, we report two cost-effective systems for the expression and purification of recombinant human CUL2 from E. coli cells. The purified CUL2 proteins were ~ 95% pure, could bind their substrate receptor modules, and were enzymatically active in transferring ubiquitin or ubiquitin-like protein to the corresponding substrate in in vitro assays. The presented methodological advancements will help advance research in CRL2 function and regulation.
| S-EPMC8160325 | biostudies-literature
Project description:Recombinant flounder growth hormone was overproduced in E. coli by using codon optimized synthetic gene and optimized expression conditions for high level production. The gene was cloned into PET-28a expression vector and transformed into E. coli BL21 (DE3). Induction at lower temperature, lower IPTG concentrations and richer growth media during expression resulted in increased expression level. The protein expression profile was analyzed by SDS-PAGE, the authenticity was confirmed by western blotting and the concentration was determined by Bradford assay. In addition, several attempts were made to produce soluble product and all resulted in insoluble product. The overexpressed protein was efficiently purified from inclusion bodies by moderate speed centrifugation after cell lysis. Among the solubilization buffers examined, buffer with 1% N-lauroylsarcosine in the presence of reducing agent DTT at alkaline pH resulted in efficient solubilization and recovery. The denaturant was removed by filtration and dialysis. The amount of the growth hormone recovered was significantly higher than previous reports that expressed native growth hormone genes in E. coli. The methodology adapted in this study, can be used to produce flounder growth hormone at large scale level so that it can be used in aquaculture. This approach may also apply to other proteins if high level expression and efficient purification is sought in E. coli.
| S-EPMC6353774 | biostudies-literature
Project description:BackgroundThe use of bovine-origin ribonucleases has been part of the standard protocol for plasmid DNA purification. As the field of gene therapy now enters the clinical stage, such enzymes need to be phased out or alternative purification protocols need to be developed to ensure product safety and regulatory compliance. The recombinant expression of bacterial RNase is fraught with toxicity problems making it a challenging enzyme to express. The current study describes a plasmid construct that allowed expression of barnase in Escherichia coli under co-expression of its native inhibitor barstar.ResultsThe pure enzyme without the inhibitor barstar was exported to the extracellular space through the periplasm and then purified from the cell-free supernatant. Cation exchange chromatography was employed as a primary purification step. This was followed by hydrophobic interaction chromatography which resulted in a concentrated fraction of active enzyme. Although current levels of volumetric activity achieved are quite meagre (4 Kunitz units mL- 1), in principle its application to plasmid DNA purification could be proved. Currently, this is capable of processing small amounts (13 g) of bacterial biomass for plasmid production.ConclusionsThe current work focusses on the downstream purification strategies for a recombinant RNase and sets a framework for higher scale production if specific productivity is increased by optimal hosts and/or re-engineered plasmids. Also important is to curtail the massive enzyme loss during purification by cation exchange chromatography. Application of even a relatively small amount of recombinant RNase would contribute to greatly reducing the initial RNA levels in alkaline lysates thereby augmenting further downstream plasmid purification steps.
| S-EPMC8403359 | biostudies-literature
Project description:Cholesterol oxidase is a bacterial flavoenzyme which catalyzes oxidation and isomerization of cholesterol. This enzyme has a great commercial value because of its wide applications in cholesterol analysis of clinical samples, synthesis of steroid-derived drugs, food industries, and potentially insecticidal activity. Accordingly, development of an efficient protocol for overexpression of cholesterol oxidase can be very valuable and beneficial. In this study, expression optimization of cholesterol oxidase from Streptomyces sp. SA-COO was investigated in Escherichia coli host strains. Various parameters that may influence the yield of a recombinant enzyme were evaluated individually. The optimal host strain, culture media, induction time, Isopropyl ß-D-1-thiogalactopyranoside concentration, as well as post-induction incubation time and temperature were determined in a shaking flask mode. Applying the optimized protocol, the production of recombinant cholesterol oxidase was significantly enhanced from 3.2 to 158 U/L. Under the optimized condition, the enzyme was produced on a large-scale, and highly expressed cholesterol oxidase was purified from cell lysate by column nickel affinity chromatography. Km and Vmax values of the purified enzyme for cholesterol were estimated using Lineweaver-Burk plot. Further, the optimum pH and optimum temperature for the enzyme activity were also determined. We report a straightforward and easy protocol for cholesterol oxidase production which can be performed in any laboratory.
| S-EPMC6232189 | biostudies-literature
Project description:Adenylate kinase (AK) from Escherichia coli was used as both solubility and affinity tag for recombinant protein production. When fused to the N-terminus of a target protein, an AK fusion protein could be expressed in soluble form and purified to near homogeneity in a single step from Blue-Sepherose via affinity elution with micromolar concentration of P1, P5- di (adenosine-5') pentaphosphate (Ap5A), a transition-state substrate analog of AK. Unlike any other affinity tags, the level of a recombinant protein expression in soluble form and its yield of recovery during each purification step could be readily assessed by AK enzyme activity in near real time. Coupled to a His-Tag installed at the N-terminus and a thrombin cleavage site at the C terminus of AK, the streamlined method, here we dubbed AK-TAG, could also allow convenient expression and retrieval of a cleaved recombinant protein in high yield and purity via dual affinity purification steps. Thus AK-TAG is a new addition to the arsenal of existing affinity tags for recombinant protein expression and purification, and is particularly useful where soluble expression and high degree of purification are at stake.
| S-EPMC4877045 | biostudies-literature
Project description:Glycine N-acyltransferase (GLYAT) is a phase II metabolic detoxification enzyme for exogenous (xenobiotic) and endogenous carboxylic acids; consisting of fatty acids, benzoic acid, and salicylic acid. GLYAT catalyzes the formation of hippurate (N-benzoylglycine) from the corresponding glycine and benzoyl-CoA. Herein, we report the successful expression, purification, and characterization of recombinant mouse GLYAT (mGLYAT). A 34kDa mGLYAT protein was expressed in Escherichia coli and purified to homogeneity by nickel affinity chromatography to a final yield of 2.5mg/L culture. Characterization for both amino donors and amino acceptors were completed, with glycine serving as the best amino donor substrate, (kcat/Km)app=(5.2±0.20)×10(2)M(-1)s(-1), and benzoyl-CoA serving as the best the amino acceptor substrate, (kcat/Km)app=(4.5±0.27)×10(5)M(-1)s(-1). Our data demonstrate that mGLYAT will catalyzed the chain length specific (C2-C6) formation of N-acylglycines. The steady-state kinetic constants determined for recombinant mGLYAT for the substrates benzoyl-CoA and glycine, were shown to be consistent with other reported species (rat, human, bovine, ovine, and rhesus monkey). The successful recombinant expression and purification of mGLYAT can lead to solve unanswered questions associated with this enzyme, consisting of what is the chemical mechanism and what catalytic residues are essential for the how this phase II metabolic detoxification enzyme conjugates glycine to xenobiotic and endogenous carboxylic acids.
| S-EPMC3985065 | biostudies-literature
Project description:Complications related to atherosclerosis account for approximately 1 in 4 deaths in the United States and treatment has focused on lowering serum LDL-cholesterol levels with statins. However, approximately 50% of those diagnosed with atherosclerosis have blood cholesterol levels within normal parameters. Human fortilin is an anti-apoptotic protein and a factor in macrophage-mediated atherosclerosis and is hypothesized to protect inflammatory macrophages from apoptosis, leading to subsequent cardiac pathogenesis. Fortilin is unique because it provides a novel drug target for atherosclerosis that goes beyond lowering cholesterol and utilization of a solution nuclear magnetic resonance (NMR) spectroscopy, structure-based drug discovery approach requires milligram quantities of pure, bioactive, recombinant fortilin. Here, we designed expression constructs with different affinity tags and protease cleavage sites to find optimal conditions to obtain the quantity and purity of protein necessary for structure activity relationship studies. Plasmids encoding fortilin with maltose binding protein (MBP), 6-histidine (6His) and glutathione-S-transferase (GST), N- terminal affinity tags were expressed and purified from Escherichia coli (E. coli). Cleavage sites with tobacco etch virus (TEV) protease and human rhinovirus (HRV) 3C protease were assessed. Despite high levels of expression of soluble protein, the fusion constructs were resistant to proteinases without the inclusion of amino acids between the cleavage site and N-terminus. We surveyed constructs with increasing lengths of glycine/serine (GGS) linkers between the cleavage site and fortilin and found that inclusion of at least one GGS insert led to successful protease cleavage and pure fortilin with conserved binding to calcium as measured by NMR.
| S-EPMC8557625 | biostudies-literature
Project description:Aggregation of amyloid-β protein (Aβ) is hypothesized to be a seminal neuropathological event in Alzheimer's disease (AD). Recombinant expression and purification of Aβ represents a common basis for investigating the molecular mechanisms of amyloid formation and toxicity. Herein, we report a novel high-yield expression and purification method for Aβ42 based on fusion with maltose binding protein (MBP) followed by the soluble polypeptide linker (NANP)3 and a modified tobacco etch virus (TEV) cleavage site before the Aβ42. We obtained a final yield of ∼18 mg L-1 of recombinant Aβ42 that was confirmed by SDS-PAGE, protein immunoblotting and MALDI-TOF. Finally, thioflavin T fluorescence and atomic force microscopy revealed that the recombinant Aβ42 aggregated into long, branched fibrils. Furthermore, the aggregates of the recombinant peptide had a strong cytotoxic effect on PC12 cells. The method described here can therefore be used to efficiently express the soluble fusion protein MBP-Aβ42 and obtain high-purity Aβ42 peptide, which can be used to understand the molecular mechanism of Aβ42 fibrillization and screen new candidate drugs for AD.
| S-EPMC9087987 | biostudies-literature