| 1. |
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| 2. |
- Dannemeyer, Melanie, et al.
(författare)
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Fast and robust recombinant protein production utilizing episomal stable pools in WAVE bioreactors
- 2024
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Ingår i: Protein Expression and Purification. - : Elsevier BV. - 1046-5928 .- 1096-0279. ; 221
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Tidskriftsartikel (refereegranskat)abstract
- Protein reagents are essential resources for several stages of drug discovery projects from structural biology and assay development through lead optimization. Depending on the aim of the project different amounts of pure protein are required. Small-scale expressions are initially used to determine the reachable levels of production and quality before scaling up protein reagent supply. Commonly, amounts of several hundreds of milligrams to grams are needed for different experiments, including structural investigations and activity evaluations, which require rather large cultivation volumes. This implies that cultivation of large volumes of either transiently transfected cells or stable pools/stable cell lines is needed. Hence, a production process that is scalable, speeds up the development projects, and increases the robustness of protein reagent quality throughout scales. Here we present a protein production pipeline with high scalability. We show that our protocols for protein production in Chinese hamster ovary cells allow for a seamless and efficient scale-up with robust product quality and high performance. The flexible scale of the production process, as shown here, allows for shorter lead times in drug discovery projects where there is a reagent demand for a specific protein or a set of target proteins.
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| 3. |
- Grāve, Kristīne, 1988-, et al.
(författare)
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High-throughput strategy for identification of Mycobacterium tuberculosis membrane protein expression conditions using folding reporter GFP
- 2022
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Ingår i: Protein Expression and Purification. - : Elsevier BV. - 1046-5928 .- 1096-0279. ; 198
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Tidskriftsartikel (refereegranskat)abstract
- Mycobacterium tuberculosis membrane protein biochemistry and structural biology studies are often hampered by challenges in protein expression and selection for well-expressing protein candidates, suitable for further investigation. Here we present a folding reporter GFP (frGFP) assay, adapted for M. tuberculosis membrane protein screening in Escherichia coli Rosetta 2 (DE3) and Mycobacterium smegmatis mc24517. This method allows protein expression condition screening for multiple protein targets simultaneously by monitoring frGFP fluorescence in growing cells. We discuss the impact of common protein expression conditions on 42 essential M. tuberculosis H37Rv helical transmembrane proteins and establish the grounds for their further analysis. We have found that the basal expression of the lac operon in the T7-promoter expression system generally leads to high recombinant protein yield in M. smegmatis, and we suggest that a screening condition without the inducer is included in routine protein expression tests. In addition to the general observations, we describe conditions allowing high-level expression of more than 25 essential M. tuberculosis membrane proteins, containing 2 to 13 transmembrane helices. We hope that these findings will stimulate M. tuberculosis membrane protein research and aid the efforts in drug development against tuberculosis.
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| 4. |
- Jarrott, Russell J., et al.
(författare)
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Expression, purification and characterization of the suppressor of copper sensitivity (Scs) B membrane protein from Proteus mirabilis
- 2022
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Ingår i: Protein Expression and Purification. - : Elsevier BV. - 1046-5928 .- 1096-0279. ; 193
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Tidskriftsartikel (refereegranskat)abstract
- Suppressor of copper sensitivity (Scs) proteins play a role in the bacterial response to copper stress in many Gram-negative bacteria, including in the human pathogen Proteus mirabilis. Recently, the ScsC protein from P. mirabilis (PmScsC) was characterized as a trimeric protein with isomerase activity that contributes to the ability of the bacterium to swarm in the presence of copper. The CXXC motif catalytic cysteines of PmScsC are maintained in their active reduced state by the action of its membrane-bound partner protein, the Proteus mirabilis ScsB (PmScsB). Thus, PmScsC and PmScsB form a redox relay in vivo. The predicted domain arrangement of PmScsB comprises a central transmembrane β-domain and two soluble, periplasmic domains, the N-terminal α-domain and C-terminal γ-domain. Here, we provide a procedure for the recombinant expression and purification of the full-length PmScsB protein. Using Lemo21 (DE3) cells we expressed PmScsB and, after extraction and purification, we were able to achieve a yield of 3 mg of purified protein per 8 L of bacterial culture. Furthermore, using two orthogonal methods - AMS labelling of free thiols and a scrambled RNase A activity assay - PmScsB is shown to catalyze the reduction of PmScsC. Our results demonstrate that the PmScsC and PmScsB redox relay can be reconstituted in vitro using recombinant full-length PmScsB membrane protein. This finding provides a promising starting point for the in vitro biochemical and structural characterization of the P. mirabilis ScsC and ScsB interaction.
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| 5. |
- Kanje, Sara, 1986-, et al.
(författare)
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Improvements of a high-throughput protein purification process using a calcium-dependent setup
- 2020
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Ingår i: Protein Expression and Purification. - : Elsevier BV. - 1046-5928 .- 1096-0279. ; 175
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Tidskriftsartikel (refereegranskat)abstract
- The Human Secretome Project aims to produce and purify all human secreted proteins as full-length. In order to enable this, a robust, gentle and effective purification process is needed, where multiple proteins can be purified in parallel. For this reason, a purification system based on a Protein C-tag and the HPC4 antibody with high affinity to the tag was chosen for purification. The strong binding between the tag and the antibody is specific and calcium-dependent, which allows for mild elution with EDTA. Presented here is a study comparing different protein purification base matrices coupled with the HPC4 antibody, aiming to increase the yield of purified protein and reduce the time for purification. Among the different tested matrices, Capto XP showed a high coupling degree and increased the amount of eluted protein as compared to the control matrix. By moving from batch incubation to direct sample loading and by performing the purification on the aKTAxpress, an automated protein purification process and a high reduction of hands-on sample handling was achieved. This new method also integrates the desalting step in the purification process, and the time for purification and analysis of each sample was decreased from five to three days. Moreover, a new mild method for matrix regeneration was developed using 50 mM EDTA pH 7.5 instead of 0.1 M glycine pH 2. This method was proven to be efficient for regeneration while maintaining the column binding performance even after nine rounds of regeneration.
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| 6. |
- Phoeurk, Chanrith, et al.
(författare)
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Milligram scale expression, refolding, and purification of Bombyx mori cocoonase using a recombinant E. coli system
- 2021
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Ingår i: Protein Expression and Purification. - : Elsevier. - 1046-5928 .- 1096-0279. ; 186
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Tidskriftsartikel (refereegranskat)abstract
- Silk is one of the most versatile biomaterials with signature properties of outstanding mechanical strength and flexibility. A potential avenue for developing more environmentally friendly silk production is to make use of the silk moth (Bombyx mori) cocoonase, this will at the same time increase the possibility for using the byproduct, sericin, as a raw material for other applications. Cocoonase is a serine protease utilized by the silk moth to soften the cocoon to enable its escape after completed metamorphosis. Cocoonase selectively degrades the glue protein of the cocoon, sericin, without affecting the silk-fiber made of the protein fibroin. Cocoonase can be recombinantly produced in E. coli, however, it is exclusively found as insoluble inclusion bodies. To solve this problem and to be able to utilize the benefits associated with an E. coli based expression system, we have developed a protocol that enables the production of soluble and functional protease in the milligram/liter scale. The core of the protocol is refolding of the protein in a buffer with a redox potential that is optimized for formation of native and intramolecular di-sulfide bridges. The redox potential was balanced with defined concentrations of reduced and oxidized glutathione. This E. coli based production protocol will, in addition to structure determination, also enable modification of cocoonase both in terms of catalytic function and stability. These factors will be valuable components in the development of alternate silk production methodology.
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| 7. |
- Wang, Zuoneng, 1991-, et al.
(författare)
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Optimizing purification of the peripheral membrane protein FAM92A1 fused to a modified spidroin tag
- 2022
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Ingår i: Protein Expression and Purification. - : Elsevier. - 1046-5928 .- 1096-0279. ; 189, s. 105992-105992
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Cryo-electron microscopy has revolutionized structural biology. In particular structures of proteins at themembrane interface have been a major contribution of cryoEM. Yet, visualization and characterization of peripheralmembrane proteins remains challenging; mostly because there is no unified purification strategy forthese proteins. FAM92A1 is a novel peripheral membrane protein that binds to the mitochondrial inner membrane.There, FAM92A1 dimers bind to the membrane and play an essential role in regulating the mitochondrialultrastructure. Curiously, FAM92A1 has also an important function in ciliogenesis. FAM92A1 is part of themembrane bending Bin1/Amphiphsyin/RVS (BAR) domain protein family. Currently, there is no structure ofFAM92A1, mostly because FAM92A1 is unstable and insoluble at high concentrations, like many BAR domainproteins. Yet, pure and concentrated protein is a necessity for screening to generate samples suitable for structuredetermination. Here, we present an optimized purification and expression strategy for dimeric FAM92A1. To ourknowledge, we are the first to use the spidroin tag NT* to successfully purify a peripheral membrane protein. Ourresults show that NT* not only increases solubility but stabilizes FAM92A1 as a dimer. FAM92A1 fused to NT* isactive because it is able to efficiently bend membranes. Taken together, our strategy indicates that this is apossible avenue to express and purify other challenging BAR domain proteins.
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| 8. |
- Zhu, Jie, et al.
(författare)
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Highly secretory expression of recombinant cowpea chlorotic mottle virus capsid proteins in Pichia pastoris and in-vitro encapsulation of ruthenium nanoparticles for catalysis
- 2020
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Ingår i: Protein Expression and Purification. - : Elsevier BV. - 1046-5928 .- 1096-0279. ; 174
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Tidskriftsartikel (refereegranskat)abstract
- The applications of viral protein cages have expanded rapidly into the fields of bionanotechnology and materials science. However, the low-cost production of viral capsid proteins (CPs) on a large scale is always a challenge. Herein, we develop a highly efficient expression system by constructing recombinant Pichia pastoris cells as a “factory” for the secretion of soluble cowpea chlorotic mottle virus (CCMV) CPs. Under optimal induction conditions (0.9 mg/mL of methanol concentration at 30 °C for 96 h), a high yield of approximately 95 mg/L of CCMV CPs was harvested from the fermentation supernatant with CPs purity >90%, which has significantly simplified the rest of the purification process. The resultant CPs are employed to encapsulate Ruthenium (Ru) nanoparticles (NPs) via in-vitro self-assembly to prepare hybrid nanocatalyst, i.e. Ru@virus-like particles (VLPs). The catalytic activity over Ru@VLPs was evaluated by reducing 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). The results indicate that, with the protection of protein cages, Ru NPs were highly stabilized during the catalytic reaction. This results in enhanced catalytic activity (reaction rate constant k = 0.14 min−1) in comparison with unsupported citrate-stabilized Ru NPs (Ru-CA) (k = 0.08 min−1). Additionally, comparatively lower activation energy over Ru@VLPs (approximately 32 kJ/mol) than that over Ru-CA (approximately 39 kJ/mol) could be attributed to the synergistic effect between Ru NPs and some functional groups such as amino groups (–NH2) on CPs that weakened the activation barrier of 4-NP reduction. Therefore, enhanced activity and decreased activation energy over Ru@VLPs demonstrated the superiority of Ru@VLPs to unsupported Ru-CA.
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| 9. |
- Ådén, Jörgen, 1980-, et al.
(författare)
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A novel recombinant expression and purification approach for the full-length anti-apoptotic membrane protein Bcl-2
- 2020
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Ingår i: Protein Expression and Purification. - : Elsevier. - 1046-5928 .- 1096-0279. ; 172
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Tidskriftsartikel (refereegranskat)abstract
- Programmed cell death (apoptosis) is an essential mechanism in life that tightly regulates embryogenesis and removal of harmful cells. Besides an extrinsic pathway, an intrinsic (mitochondrial) apoptotic pathway exists where mitochondria are actively involved in cellular clearance in response to internal stress signals. Pro-apoptotic (death) and anti-apoptotic (survival) members of the B cell CLL/lymphoma-2 (Bcl-2) protein family meet at the mitochondrion's surface where they accurately regulate apoptosis. Overexpression of the anti-apoptotic Bcl-2 protein is a hallmark for many types of cancers and in particular for many treatment resistant tumors. Bcl-2 is a membrane protein residing in the mitochondrial outer membrane. Due to its typical membrane protein features including very limited solubility, it is difficult to express and to purify. Therefore, most biophysical and structural studies have used truncated, soluble versions. However, to understand its membrane-coupled function and structure, access to sufficient amount of full-length human Bcl-2 protein is a necessity. Here, we present a novel, E. coli based approach for expression and purification of preparative amounts of the full-length human isoform 2 of Bcl-2 (Bcl-2(2)), solubilized in detergent micelles, which allows for easy exchange of the detergent.
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| 10. |
- Aggarwal, Swati, et al.
(författare)
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A protocol for production of perdeuterated OmpF porin for neutron crystallography
- 2021
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Ingår i: Protein Expression and Purification. - : Elsevier BV. - 1046-5928. ; 188
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Tidskriftsartikel (refereegranskat)abstract
- Hydrogen atoms are at the limit of visibility in X-ray structures even at high resolution. Neutron macromolecular crystallography (NMX) is an unambiguous method to locate hydrogens and study the significance of hydrogen bonding interactions in biological systems. Since NMX requires very large crystals, very few neutron structures of proteins have been determined yet. In addition, the most common hydrogen isotope 1H gives rise to significant background due to its large incoherent scattering cross-section. Therefore, it is advantageous to substitute as many hydrogens as possible with the heavier isotope 2H (deuterium) to reduce the sample volume requirement. While the solvent exchangeable hydrogens can be substituted by dissolving the protein in heavy water, complete deuterium labelling – perdeuteration – requires the protein to be expressed in heavy water with a deuterated carbon source. In this work, we developed an optimized method for large scale production of deuterium-labelled bacterial outer membrane protein F (OmpF) for NMX. OmpF was produced using deuterated media with different carbon sources. Mass spectrometry verified the integrity and level of deuteration of purified OmpF. Perdeuterated OmpF crystals diffracted X-rays to a resolution of 1.9 Å. This work lays the foundation for structural studies of membrane protein by neutron diffraction in future.
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| 11. |
- Frankel, Rebecca, et al.
(författare)
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Purification and HDL-like particle formation of apolipoprotein A-I after co-expression with the EDDIE mutant of Npro autoprotease
- 2021
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Ingår i: Protein Expression and Purification. - : Elsevier BV. - 1046-5928. ; 187
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Tidskriftsartikel (refereegranskat)abstract
- Apolipoprotein A-I (ApoA-I) is the major protein constituent of high-density lipoprotein particles, and as such is involved in cholesterol transport and activation of LCAT (the lecithin:cholesterol acyltransferase). It may also form amyloidal deposits in the body, showing the multifaceted interactions of ApoA-I. In order to facilitate the study of ApoA-I in various systems, we have developed a protocol based on recombinant expression in E. coli. ApoA-I is protected from degradation by driving its expression to inclusion bodies using a tag: the EDDIE mutant of Npro autoprotease from classical swine fever virus. Upon refolding, EDDIE will cleave itself off from the target protein. The result is a tag-free ApoA-I, with its N-terminus intact. ApoA-I was then purified using a five-step procedure composed of anion exchange chromatography, immobilized metal ion affinity chromatography, hydrophobic interaction chromatography, boiling and size exclusion chromatography. This led to protein of high purity as confirmed with SDS-PAGE and mass spectrometry. The purified ApoA-I formed discoidal objects in the presence of zwitterionic phospholipid DMPC, showing its retained function of interacting with lipids. The protocol was also tested by expression and purification of two ApoA-I mutants, both of which could be purified in the same manner as the wildtype, showing the robustness of the protocol.
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| 12. |
- Nayeri, Niloofar, et al.
(författare)
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Principles to recover copper-conducting CTR proteins for the purpose of structural and functional studies
- 2023
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Ingår i: Protein Expression and Purification. - : Elsevier BV. - 1046-5928. ; 203
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Tidskriftsartikel (refereegranskat)abstract
- Transition metals such as copper and zinc are essential elements required for the survival of most organisms, from bacteria to humans. Yet, elevated levels of these elements are highly toxic. The Copper TRansporter protein family (CTRs) represents the only identified copper uptake proteins in eukaryotes and hence serves as key components for the maintenance of appropriate levels of the metal. Moreover, CTRs have been proposed to serve as an entry point into cells of certain cancer drugs and to constitute attractive drug-targets for novel antifungals. Nevertheless, the structure, function, and regulation of the CTRs remain elusive, limiting valuable information also for applied sciences. To this end, here we report procedures to isolate a range of CTR members using Saccharomyces cerevisiae as a production host, focusing on three homologs, human CTR1, human CTR2, and Candida albicans CTR. Using forms C-terminally-linked to a protease cleavage sequence, Green Fluorescent Protein (GFP), and a His-tag, assessment of the localization, quantification and purification was facilitated. Cellular accumulation of the proteins was investigated via live-cell imaging. Detergents compatible with acceptable solubilization yields were identified and fluorescence-detection size-exclusion-chromatography (F-SEC) revealed preferred membrane extraction conditions for the targets. For purification purposes, the solubilized CTR members were subjected to affinity chromatography and SEC, reaching near homogeneity. The quality and quantity of the CTRs studied will permit downstream efforts to uncover imperative biophysical aspects of these proteins, paving the way for subsequent drug-discovery studies.
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| 13. |
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| 14. |
- Weick, Linn, 1991, et al.
(författare)
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Patient experience of implant loss after immediate breast reconstruction : An interpretative phenomenological analysis
- 2023
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Ingår i: Health Care for Women International. - : Taylor & Francis Group. - 0739-9332 .- 1096-4665. ; 44:1, s. 61-79
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Tidskriftsartikel (refereegranskat)abstract
- Immediate breast reconstruction (IBR) is an integral part of modern breast cancer treatment. Our aim was to investigate patient experience with implant loss after IBR by using interpretative phenomenological analysis (IPA). We conducted semi-structured interviews with eight informants. We analyzed data according to the IPA flexible seven-stage process and four main themes were developed: immediate breast reconstruction as the indisputable choice, a difficult experience, an altered body: redefining normality, and trying to cope. The experience of implant loss appears to affect women for many years and might overshadow some of the benefits of IBR.
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