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  • 1. Ahl, Ing-Marie
    et al.
    Lindberg, Mikael J
    Umeå University, Faculty of Science and Technology, Chemistry.
    Tibell, Lena A E
    Coexpression of yeast copper chaperone (yCCS) and CuZn-superoxide dismutases in Escherichia coli yields protein with high copper contents2004In: Protein Expression and Purification, ISSN 1046-5928, E-ISSN 1096-0279, Vol. 37, no 2, p. 311-9Article in journal (Refereed)
    Abstract [en]

    To fully understand the function of the Cu- and Zn-containing superoxide dismutases in normal and disordered cells, it is essential to study protein variants with full metal contents. We describe the use of an Escherichia coli-based expression system for the overproduction of human intracellular wild type CuZn-superoxide dismutase (SOD), the CuZnSOD variant F50E/G51E (monomeric), two amyotrophic lateral sclerosis-related mutant CuZnSOD variants (D90A and G93A), and PseudoEC-SOD, all with high Cu contents. This system is based on coexpression of the SOD variants with the yeast copper chaperone yCCS during growth in a medium supplemented with Cu(2+) and Zn(2+). The recombinant SOD enzymes were all found in the cytosol and represented 30-50% of the total bacterial protein. The enzymes were purified to homogeneity and active enzymes were obtained in high yield. The resulting proteins were characterized through immunochemical reactivity and specific activity analyses, in conjunction with mass-, photo-, and atomic absorption-spectroscopy.

  • 2. Barrera, Daniel Iván
    et al.
    Matheus, Luisa Marina
    Stigbrand, Torgny
    Umeå University, Faculty of Medicine, Clinical Microbiology. Umeå University, Faculty of Medicine, Clinical Microbiology, Immunology/Immunchemistry.
    Arbeláez, Luis Fernando
    Proteolytic hydrolysis and purification of the LRP/alfa-2-macroglobulin receptor domain from alpha-macroglobulins.2007In: Protein Expression and Purification, ISSN 1046-5928, E-ISSN 1096-0279, Vol. 53, no 1, p. 112-8Article in journal (Refereed)
    Abstract [en]

    A new, easier and efficient purification method, using Sephacryl and DEAE-Sephacel, of the C-terminal fragment of two alpha-macroglobulins, alpha(2)-M and PZP, is presented. Two larger peptides were identified for each protein as the C-terminal fragment, with molecular weights of approximately 30 kDa and the N-terminal sequences were determined to be SSTQDTV for alpha(2)-M and VALHLS for PZP. The smaller peptides with molecular weights of 18 kDa correspond to a shorter C-terminal sequence of these proteins, and they were determined to be EEFPFA for alpha(2)-M and ALKVQTV for PZP, with no interfering sequences detected. The results confirmed the discriminatory capacity of the purification procedure and the purity of the fragments. This new methodology facilitates biological studies of alpha-macroglobulins, and will enable elucidation of the role the C-terminal region may exert to eliminate alpha-macroglobulin-proteinases complexes from the circulation by the LRP/receptor.

  • 3. Bogomolovas, Julius
    et al.
    Simon, Bernd
    Sattler, Michael
    Stier, Gunter
    Umeå University, Faculty of Science and Technology, Umeå Centre for Molecular Pathogenesis (UCMP). Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
    Screening of fusion partners for high yield expression and purification of bioactive viscotoxins2009In: Protein Expression and Purification, ISSN 1046-5928, E-ISSN 1096-0279, Vol. 64, no 1, p. 16-23Article in journal (Refereed)
    Abstract [en]

    Viscotoxins are small cationic proteins found in European mistletoe Viscum album. They are highly toxic towards phytopathogenic fungi and cancer cells. Heterologous expression of viscotoxins would broaden the spectrum of methods to be applied for better understanding of their structure and function and satisfy possible biopharmaceutical needs. Here, we evaluated 13 different proteins as a fusion partners for expression in Escherichia coli cells: His6 tag and His6-tagged versions of GB1, ZZ tag, Z tag, maltose binding protein, NusA, glutathione S-transferase, thioredoxin, green fluorescent protein, as well as periplasmic and cytosolic versions of DsbC and DsbA. The fusion to thioredoxin gave the highest yield of soluble viscotoxin. The His6-tagged fusion protein was captured with Ni(2+) affinity chromatography, subsequently cleaved with tobacco etch virus protease. Selective precipitation by acidification of the cleavage mixture was followed by cation exchange chromatography. This protocol yielded 5.2 mg of visctoxin A3 from 11 of culture medium corresponding to a recovery rate of 68%. Mass spectrometry showed a high purity of the sample and the presence of three disulfide bridges in the recombinant viscotoxin. Proper folding of the protein was confirmed by heteronuclear NMR spectra recorded on a uniformly 15N-labeled sample. Recombinant viscotoxins prepared using this protocol are toxic to HeLa cells and preserve the activity differences between isoforms B and A3 found in native proteins.

  • 4.
    Dingeldein, Artur P. G.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Lindberg, Mikael J.
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Zhong, Xueyin
    Stoll, Raphael
    Gröbner, Gerhard
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Bax to the future – A novel, high-yielding approach for purification and expression of full-length Bax protein for structural studies2019In: Protein Expression and Purification, ISSN 1046-5928, E-ISSN 1096-0279, Vol. 158, p. 20-26Article in journal (Refereed)
    Abstract [en]

    Mitochondria-mediated apoptosis (programmed cell death) involves a sophisticated signaling and regulatory network that is regulated by the Bcl-2 protein family. Members of this family have either pro- or anti-apoptotic functions. An important pro-apoptotic member of this family is the cytosolic Bax. This protein is crucial for the onset of apoptosis by perforating the mitochondrial outer membrane (MOM). This process can be seen as point of no return, since disintegration of the MOM leads to the release of apotogenic factors such as cytochrome c into the cytosol triggering the activation of caspases and subsequent apoptotic steps. Bax is able to interact with the MOM with both its termini, making it inherently difficult to express in E. coli. In this study, we present a novel approach to express and purify full-length Bax with significantly increased yields, when compared to the commonly applied strategy. Using a double fusion approach with an N-terminal GST-tag and a C-terminal Intein-CBD-tag, we were able to render both Bax termini inactive and prevent disruptive interactions from occurring during gene expression. By deploying an Intein-CBD-tag at the C-terminus we were further able to avoid the introduction of any artificial residues, hence ensuring the native like activity of the membrane-penetrating C-terminus of Bax. Further, by engineering a His6-tag to the C-terminus of the CBD-tag we greatly improved the robustness of the purification procedure. We report yields for pure, full-length Bax protein that are increased by an order of magnitude, when compared to commonly used Bax expression protocols.

  • 5.
    Dingeldein, Artur Peter Günther
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Lindberg, Mikael
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Zhong, Xueyin
    Ruhr University of Bochum, Biomolecular NMR Spectroscopy.
    Stoll, Raphael
    Ruhr University of Bochum, Biomolecular NMR Spectroscopy.
    Gröbner, Gerhard
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Bax to the future: A novel, high-yielding approach for purification and expression of full-length Bax protein for structural studiesIn: Protein Expression and Purification, ISSN 1046-5928, E-ISSN 1096-0279Article in journal (Refereed)
    Abstract [en]

    Mitochondria-mediated apoptosis (programmed cell death) is tightly regulated by the B-cell CLL/lymphoma-2 (Bcl-2) protein family. The members of this family can be divided into pro- and anti-apoptotic functioning proteins. One of the most important members for executing apoptosis is the cytosolic apoptotic Bax protein. It is crucial in facilitating onset of apoptosis by disrupting and forming pores within the mitochondrial outer membrane (MOM). This pore formation is commonly viewed as a point of no return, since it releases apotogenic factors such as cytochrome c into the cytosol who trigger irreversibly cell death by caspase activation and nuclear fragmentation. Bax is able to interact with the MOM with both its termini, making it inherently difficult to express in E. coli due to the strong similarities between both membrane-active segments. Here, we present a novel approach to express and purify full-length Bax with significantly increased yields compared to the commonly applied strategy with very bad yields. Using a double fusion approach with an N-terminal GST-tag and a C-terminal Intein-CBD-tag, we rendered both Bax termini inactive and prevented disruptive interactions during gene expression. By deploying an Intein-CBD-tag at the C-terminus we avoided even the introduction of any artificial residues, hence ensuring the native like activity of the membrane-penetrating C-terminus of Bax. Further, by engineering a His6-tag to the C-terminus of the CBD-tag we greatly improved the purification procedure. Yields for pure, full-length Bax protein are increased by an order of magnitude, compared to commonly used Bax expression protocols.

  • 6.
    Edwin, Aaron
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Grundström, Christin
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Wai, Sun Nyunt
    Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS). Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology).
    Öhman, Anders
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Stier, Gunter
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sauer-Eriksson, A Elisabeth
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Domain isolation, expression, purification and proteolytic activity of the metalloprotease PrtV from Vibrio cholerae2014In: Protein Expression and Purification, ISSN 1046-5928, E-ISSN 1096-0279, Vol. 96, p. 39-47Article in journal (Refereed)
    Abstract [en]

    The metalloprotease PrtV from Vibrio cholerae serves an important function for the bacteria's ability to invade the mammalian host cell. The protein belongs to the family of M6 proteases, with a characteristic zinc ion in the catalytic active site. PrtV constitutes a 918 amino acids (102kDa) multidomain pre-pro-protein that so far has only been expressed in V. cholerae. Structural studies require high amounts of soluble protein with high purity. Previous attempts for recombinant expression have been hampered by low expression and solubility of protein fragments. Here, we describe results from parallel cloning experiments in Escherichia coli where fusion tagged constructs of PrtV fragments were designed, and protein products tested for expression and solubility. Of more than 100 designed constructs, three produced protein products that expressed well. These include the N-terminal domain (residues 23-103), the PKD1 domain (residues 755-839), and a 25kDa fragment (residues 581-839). The soluble fusion proteins were captured with Ni(2+) affinity chromatography, and subsequently cleaved with tobacco etch virus protease. Purification protocols yielded ∼10-15mg of pure protein from 1L of culture. Proper folding of the shorter domains was confirmed by heteronuclear NMR spectra recorded on (15)N-labeled samples. A modified protocol for the native purification of the secreted 81kDa pro-protein of PrtV is provided. Proteolytic activity measurements suggest that the 37kDa catalytic metalloprotease domain alone is sufficient for activity.

  • 7. Eriksson, Hanna M
    et al.
    Persson, Karina
    Umeå University, Faculty of Medicine, Department of Odontology, Cariology.
    Zhang, Shuguang
    Wieslander, Åke
    High-yield expression and purification of a monotopic membrane glycosyltransferase2009In: Protein Expression and Purification, ISSN 1046-5928, E-ISSN 1096-0279, Vol. 66, no 2, p. 143-148Article in journal (Refereed)
    Abstract [en]

    Membrane proteins are essential to many cellular processes. However, the systematic study of membrane protein structure has been hindered by the difficulty in obtaining large quantities of these proteins. Protein overexpression using Escherichia coli is commonly used to produce large quantities of protein, but usually yields very little membrane protein. Furthermore, optimization of the expressing conditions, as well as the choice of detergent and other buffer components, is thought to be crucial for increasing the yield of stable and homogeneous protein. Herein we report high-yield expression and purification of a membrane-associated monotopic protein, the glycosyltransferase monoglucosyldiacylglycerol synthase (alMGS), in E. coli. Systematic optimization of protein expression was achieved through controlling a few basic expression parameters, including temperature and growth media, and the purifications were monitored using a fast and efficient size-exclusion chromatography (SEC) screening method. The latter method was shown to be a powerful tool for fast screening and for finding the optimal protein-stabilizing conditions. For alMGS it was found that the concentration of detergent was just as important as the type of detergent, and a low concentration of n-dodecyl-beta-D-maltoside (DDM) (approximately 1x critical micelle concentration) was the best for keeping the protein stable and homogeneous. By using these simply methods to optimize the conditions for alMGS expression and purification, the final expression level increase by two orders of magnitude, reaching 170 mg of pure protein per litre culture.

  • 8. Hansson, L
    et al.
    Bergström, S
    Hernell, Olle
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Lönnerdal, B
    Nilsson, A K
    Strömqvist, M
    Expression of human milk beta-casein in Escherichia coli: comparison of recombinant protein with native isoforms.1993In: Protein Expression and Purification, ISSN 1046-5928, E-ISSN 1096-0279, Vol. 4, no 5, p. 373-81Article in journal (Refereed)
    Abstract [en]

    Studies on physiological function and on structure-function relationships of human milk beta-casein have been limited. In this study, we have introduced the human beta-casein cDNA into vectors designed for expression in Escherichia coli. The inducible T7-based expression system resulted in high-level expression of recombinant beta-casein. The recombinant beta-casein, localized intracellularly in E. coli, was purified to homogeneity and compared with purified native beta-casein, in particular with respect to phosphorylation. The E. coli-produced beta-casein was found to comigrate with the full-length, nonphosphorylated native human beta-casein isoform on SDS-PAGE. An N-terminal peptide containing all tentative phosphorylation sites was isolated from the recombinant protein and analyzed by mass spectrometry. The molecular mass as well as the migration of this peptide on reversed-phase chromatography confirmed that it was unphosphorylated.

  • 9. Kalbina, Irma
    et al.
    Lagerqvist, Nina
    Moiane, Belisario
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Andersson, Soren
    Strid, Ake
    Falk, Kerstin I.
    Arabidopsis thaliana plants expressing Rift Valley fever virus antigens: Mice exhibit systemic immune responses as the result of oral administration of the transgenic plants2016In: Protein Expression and Purification, ISSN 1046-5928, E-ISSN 1096-0279, Vol. 127, p. 61-67Article in journal (Refereed)
    Abstract [en]

    The zoonotic Rift Valley fever virus affects livestock and humans in Africa and on the Arabian Peninsula. The economic impact of this pathogen due to livestock losses, as well as its relevance to public health, underscores the importance of developing effective and easily distributed vaccines. Vaccines that can be delivered orally are of particular interest. Here, we report the expression in transformed plants (Arabidopsis thaliana) of Rift Valley fever virus antigens. The antigens used in this study were the N protein and a deletion mutant of the Gn glycoprotein. Transformed lines were analysed for specific mRNA and protein content by RT-PCR and Western blotting, respectively. Furthermore, the plant-expressed antigens were evaluated for their immunogenicity in mice fed the transgenic plants. After oral intake of fresh transgenic plant material, a proportion of the mice elicited specific IgG antibody responses, as compared to the control animals that were fed wild-type plants and of which none sero-converted. Thus, we show that transgenic plants can be readily used to express and produce Rift Valley Fever virus proteins, and that the plants are immunogenic when given orally to mice. These are promising findings and provide a basis for further studies on edible plant vaccines against the Rift Valley fever virus.

  • 10.
    Paracuellos, Patricia
    et al.
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Öhman, Anders
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sauer-Eriksson, A Elisabeth
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Uhlin, Bernt Eric
    Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS). Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Expression and purification of SfaX(II), a protein involved in regulating adhesion and motility genes in extraintestinal pathogenic Escherichia coli2012In: Protein Expression and Purification, ISSN 1046-5928, E-ISSN 1096-0279, Vol. 86, no 2, p. 127-134Article in journal (Refereed)
    Abstract [en]

    Pathogenic Escherichia coli strains commonly harbor genes involved in formation of fimbriae, such as the sfa(II) fimbrial gene cluster found in uropathogenic and newborn meningitis isolates. The sfaX(II) gene, located at the distal end of the sfa(II) operon, was recently shown to play a role in controlling virulence-related gene expression in extraintestinal pathogenic E. coli (ExPEC). Until now, detailed characterization of the SfaX(II) protein has been hampered by difficulties in obtaining large quantities of soluble protein. By a rational modeling approach, we engineered a Cys70Ser mutation, which successfully improved solubility of the protein. Here, we present the expression, purification, and initial characterization of the recombinant SfaX(IIC70S) mutant. The protein was produced in E. coli BL21 (DE3) cells grown in autoinduction culture media. The plasmid vector harbored DNA encoding the SfaX(IIC70S) protein N-terminally fused with a six histidine (H6) sequence followed by a ZZ tag (a derivative of the Staphylococcus protein A) (H6-ZZ tag). The H6-ZZ tag was cleaved off with Tobacco Etch Virus (TEV) protease and the 166 amino acid full-length homo-dimeric protein was purified using affinity and size-exclusion chromatography. Electrophoretic mobility gel shift assays and atomic force microscopy demonstrated that the protein possesses DNA-binding properties, suggesting that the transcriptional regulatory activity of SfaX(II) can be mediated via direct binding to DNA.

  • 11.
    Pedersen, Anders
    et al.
    Swedish NMR Centre, University of Gothenburg, Gothenburg, Sweden.
    Wallgren, Marcus
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Karlsson, B Göran
    Swedish NMR Centre, University of Gothenburg, Gothenburg, Sweden.
    Gröbner, Gerhard
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Expression and purification of full-length anti-apoptotic Bcl-2 using cell-free protein synthesis2011In: Protein Expression and Purification, ISSN 1046-5928, E-ISSN 1096-0279, Vol. 77, no 2, p. 220-223Article in journal (Refereed)
    Abstract [en]

    The anti-apoptotic B cell CLL/lymphoma-2 (Bcl-2) protein is a key player in the regulation of programmed cell death and is linked to various types of cancer and their resistance to drug treatment. Biophysical and structural studies of the full-length intact Bcl-2 have been hampered due to difficulties in expression and severe solubility problems, precluding isolation of this hydrophobic membrane protein. Therefore, previous work has so far mainly been carried out using structurally modified Bcl-2 variants, lacking the transmembrane region. Thus, biophysical information regarding the full-length protein is still missing. Here, a protocol is presented for expression and purification of preparative amounts of the full-length human isoform 2 of Bcl-2 (Bcl-2(2)). A batch-based cell-free expression system, using extract isolated from Escherichia coli (E. coli) was employed to produce recombinant protein encoded by an optimized gene sequence. Presence of polyoxyethylene-(20)-cetyl-ether (Brij-58) in the reaction mixture and subsequently in the immobilized metal-affinity purification steps was crucial to keep Bcl-2(2) soluble. The obtained yield was 0.25-0.3mg per ml of cell-free reaction. Far-UV circular dichroism (CD) spectroscopy confirmed the α-helical structure of the purified protein, characteristic for members of the Bcl-2 protein family.

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