Folding and processing of proteins in the endoplasmic reticulum (ER) are major impediments in the production and secretion of proteins from Pichia pastoris (Komagataella sp.). Overexpression of recombinant genes can overwhelm the innate secretory machinery of the P. pastoris cell, and incorrectly folded proteins may accumulate inside the ER. To restore proper protein folding, the cell naturally triggers an unfolded protein response (UPR) pathway, which upregulates the expression of genes coding for chaperones and other folding-assisting proteins (e.g., Kar2p, Pdi1, Ero1p) via the transcription activator Hac1p. Unfolded/misfolded proteins that cannot be repaired are degraded via the ER-associated degradation (ERAD) pathway, which decreases productivity. Co-expression of selected UPR genes, along with the recombinant gene of interest, is a common approach to enhance the production of properly folded, secreted proteins. Such an approach, however, is not always successful and sometimes, protein productivity decreases because of an unbalanced UPR. This review summarizes successful chaperone co-expression strategies in P. pastoris that are specifically related to overproduction of foreign proteins and the UPR. In addition, it illustrates possible negative effects on the cell's physiology and productivity resulting from genetic engineering of the UPR pathway. We have focused on Pichia's potential for commercial production of valuable proteins and we aim to optimize molecular designs so that production strains can be tailored to suit a specific heterologous product. KEY POINTS: • Chaperones co-expressed with recombinant genes affect productivity in P. pastoris. • Enhanced UPR may impair strain physiology and promote protein degradation. • Gene copy number of the target gene and the chaperone determine the secretion rate.

• Klíčová slova
• Chaperone, Co-expression strategy, Folding and secretion, Pichia pastoris, Productivity of recombinant protein production, Unfolded protein response (UPR),
• MeSH
• fungální proteiny * genetika   metabolismus   MeSH
• Pichia * genetika   metabolismus   MeSH
• rekombinantní proteiny genetika   metabolismus   MeSH
• Saccharomycetales MeSH
• signální dráha UPR MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• fungální proteiny * MeSH
• rekombinantní proteiny MeSH

Phlebotomus perniciosus (Diptera: Phlebotominae) is a medically and veterinary important insect vector. It transmits the unicellular parasite Leishmania infantum that multiplies intracellularly in macrophages causing life-threatening visceral diseases. Leishmania establishment in the vertebrate host is substantially influenced by immunomodulatory properties of vector saliva that are obligatorily co-injected into the feeding site. The repertoire of P. perniciosus salivary molecules has already been revealed and, subsequently, several salivary proteins have been expressed. However, their immunogenic properties have never been studied. In our study, we tested three P. perniciosus recombinant salivary proteins-an apyrase rSP01 and yellow-related proteins rSP03 and rSP03B-and showed their anti-inflammatory nature on the murine bone-marrow derived macrophages. Even in the presence of pro-inflammatory stimuli (IFN-γ and bacterial lipopolysaccharide, LPS), all three recombinant proteins inhibited nitric oxide production. Moreover, rSP03 seems to have a very strong anti-inflammatory effect since it enhanced arginase activity, increased the production of IL-10, and inhibited the production of TNF-α even in macrophages stimulated with IFN-γ and LPS. These results suggest that P. perniciosus apyrase and yellow-related proteins may serve as enhancing factors in sand fly saliva, facilitating the development of Leishmania infection along with their anti-haemostatic properties. Additionally, rSP03 and rSP03B did not elicit the delayed-type hypersensitivity response in mice pre-exposed to P. perniciosus bites (measured as visible skin reaction). The results of our study may help to understand the potential function of recombinant's native counterparts and their role in Leishmania transmission and establishment within the host.

• Klíčová slova
• Phlebotomus, apyrase, immunogenicity, macrophage polarization, sand fly saliva, yellow-related proteins,
• MeSH
• antiflogistika MeSH
• fenotyp MeSH
• makrofágy MeSH
• myši MeSH
• Phlebotomus * MeSH
• psi MeSH
• rekombinantní proteiny MeSH
• slinné proteiny a peptidy MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• psi MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antiflogistika MeSH
• rekombinantní proteiny MeSH
• slinné proteiny a peptidy MeSH

The purification of molecules from recombinant cells may be strongly influenced by the molecular biology of gene isolation and expression. At the beginning of the process there may be a demand for information on the minute amounts of proteins and thus for ever increasingly sensitive techniques. Purification of recombinant proteins can differ from conventional purifications in several ways, depending on the solubility of the protein, occurrence in inclusion bodies, creation of fusion proteins with tags that enable simpler purification. Sometimes a (re)naturation step is required to get a bioactive protein. On the other hand, the techniques used in separation are essentially the same as for purification from the natural source and environment.

• MeSH
• chromatografie kapalinová metody   MeSH
• exprese genu MeSH
• rekombinantní proteiny biosyntéza   chemie   izolace a purifikace   MeSH
• reprodukovatelnost výsledků MeSH
• sbalování proteinů MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• rekombinantní proteiny MeSH

Antibody-mediated targeting is an efficient strategy to enhance the specificity and selectivity of polymer nanomedicines towards the target site, typically a tumor. However, direct covalent coupling of an antibody with a polymer usually results in a partial damage of the antibody binding site accompanied with a compromised biological activity. Here, an original solution based on well-defined non-covalent interactions between tris-nitrilotriacetic acid (trisNTA) and hexahistidine (His-tag) groups, purposefully introduced to the structure of each macromolecule, is described. Specifically, trisNTA groups were attached along the chains of a hydrophilic statistical copolymer based on N-(2-hydroxypropyl)methacrylamide (HPMA), and at the end or along the chains of thermo-responsive di-block copolymers based on N-isopropylmethacrylamide (NIPMAM) and HPMA; His-tag was incorporated to the structure of a recombinant single chain fragment of an anti-GD2 monoclonal antibody (scFv-GD2). Static and dynamic light scattering analyses confirmed that mixing of polymer with scFv-GD2 led to the formation of polymer/scFv-GD2 complexes; those prepared from thermo-responsive polymers formed stable micelles at 37 °C. Flow cytometry and fluorescence microscopy clearly demonstrated antigen-specific binding of the prepared complexes to GD2 positive murine T-cell lymphoma cells EL-4 and human neuroblastoma cells UKF-NB3, while no interaction with GD2 negative murine fibroblast cells NIH-3T3 was observed. These non-covalent polymer protein complexes represent a new generation of highly specific actively targeted polymer therapeutics or diagnostics.

• Klíčová slova
• Hydrophilic polymers, Non-covalent attachment, Polymer drug delivery system, Recombinant proteins, Thermo-responsive polymers, Tris(nitrilotriacetic acid) ligation, Tumor-specific targeting,
• MeSH
• kyselina nitrilotrioctová MeSH
• lidé MeSH
• myši MeSH
• nádory * MeSH
• polymery * chemie   MeSH
• rekombinantní proteiny MeSH
• systémy cílené aplikace léků metody   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• hydroxypropyl methacrylate MeSH Prohlížeč
• kyselina nitrilotrioctová MeSH
• polymery * MeSH
• rekombinantní proteiny MeSH

BACKGROUND: Phlebotomus orientalis is a vector of Leishmania donovani, the causative agent of life threatening visceral leishmaniasis spread in Eastern Africa. During blood-feeding, sand fly females salivate into the skin of the host. Sand fly saliva contains a large variety of proteins, some of which elicit specific antibody responses in the bitten hosts. To evaluate the exposure to sand fly bites in human populations from disease endemic areas, we tested the antibody reactions of volunteers' sera against recombinant P. orientalis salivary antigens. METHODOLOGY/PRINCIPAL FINDINGS: Recombinant proteins derived from sequence data on P. orientalis secreted salivary proteins, were produced using either bacterial (five proteins) or mammalian (four proteins) expression systems and tested as antigens applicable for detection of anti-P. orientalis IgG in human sera. Using these recombinant proteins, human sera from Sudan and Ethiopia, countries endemic for visceral leishmaniasis, were screened by ELISA and immunoblotting to identify the potential markers of exposure to P. orientalis bites. Two recombinant proteins; mAG5 and mYEL1, were identified as the most promising antigens showing high correlation coefficients as well as good specificity in comparison to the whole sand fly salivary gland homogenate. Combination of both proteins led to a further increase of correlation coefficients as well as both positive and negative predictive values of P. orientalis exposure. CONCLUSIONS/SIGNIFICANCE: This is the first report of screening human sera for anti-P. orientalis antibodies using recombinant salivary proteins. The recombinant salivary proteins mYEL1 and mAG5 proved to be valid antigens for screening human sera from both Sudan and Ethiopia for exposure to P. orientalis bites. The utilization of equal amounts of these two proteins significantly increased the capability to detect anti-P. orientalis antibody responses.

• MeSH
• ELISA MeSH
• hmyzí proteiny genetika   imunologie   MeSH
• imunoglobulin G imunologie   MeSH
• kousnutí a bodnutí hmyzem imunologie   parazitologie   MeSH
• lidé MeSH
• Phlebotomus genetika   imunologie   fyziologie   MeSH
• rekombinantní proteiny genetika   imunologie   MeSH
• slinné proteiny a peptidy genetika   imunologie   MeSH
• sliny imunologie   MeSH
• tvorba protilátek MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• východní Afrika MeSH
• Názvy látek
• hmyzí proteiny MeSH
• imunoglobulin G MeSH
• rekombinantní proteiny MeSH
• slinné proteiny a peptidy MeSH

Francisella tularensis is a Gram-negative intracellular pathogen causing tularemia. A number of its potential virulence factors have been identified, but their biology and functions are not precisely known. Understanding the biological and immunological functions of these proteins requires adequate genetic tools for homologous and heterologous expression of cloned genes, maintaining both original structure and post-translational modifications. Here, we report the construction of a new multipurpose shuttle plasmid - pEVbr - which can be used for high-level expression in F. tularensis. The pEVbr plasmid has been constructed by modifying the TetR-regulated expression vector pEDL17 (LoVullo, 2012) that includes (i) a strong F. tularensis bfr promoter, and (ii) two tet operator sequences cloned into the promoter. The cloned green fluorescent protein (GFP), used as a reporter, demonstrated almost undetectable basal expression level under uninduced conditions and a highly dynamic dose-dependent response to the inducer. The utility of the system was further confirmed by cloning the gapA and FTT_1676 genes into the pEVbr vector and quantifying proteins expression in F. tularensis LVS, as well as by studying post-translational modification of the cloned genes. This study demonstrates that high levels of recombinant native-like Francisella proteins can be produced in Francisella cells. Hence, this system may be beneficial for the analysis of protein function and the development of new treatments and vaccines.

• Klíčová slova
• ATc inducible, Expression plasmid, Francisella tularensis, Regulated bfr promoter,
• MeSH
• Francisella tularensis * genetika   MeSH
• lidé MeSH
• plazmidy genetika   MeSH
• rekombinantní proteiny genetika   MeSH
• tetracyklin farmakologie   MeSH
• tularemie * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• rekombinantní proteiny MeSH
• tetracyklin MeSH

BACKGROUND: Certain salivary proteins of phlebotomine sand flies injected into the host skin during blood-feeding are highly antigenic and elicit strong antibody-mediated immune responses in repeatedly-exposed hosts. These antibodies can be measured by enzyme-linked immuno sorbent assays (ELISAs) using salivary gland homogenates (SGHs) as the source of antigens and serve as a markers for exposure to biting sand flies. Large-scale screening for anti-sand fly saliva antibodies requires replacement of SGH with recombinant salivary proteins. In East Africa, Phlebotomus orientalis is the main vector of Leishmania donovani, a trypanosomatid parasite causing visceral leishmaniasis. We tested recombinant salivary proteins derived from Ph. orientalis saliva to study exposure of domestic animals to this sand fly species. METHODOLOGY/PRINCIPAL FINDINGS: Antigenic salivary proteins from Ph. orientalis were identified by immunoblot and mass spectrometry. Recombinant apyrase rPorSP15, yellow-related protein rPorSP24, ParSP25-like protein rPorSP65, D7-related protein rPorSP67, and antigen 5-related protein rPorSP76 were tested using ELISA with sera of domestic animals from L. donovani foci in Ethiopia where Ph. orientalis is present. Our results highlighted recombinant yellow-related protein rPorSP24 as the most promising antigen, displaying a high positive correlation coefficient as well as good sensitivity and specificity when compared to SGH. This recombinant protein was the most suitable one for testing sera of dogs, sheep, and goats. In addition, a different antigen, rPorSP65 was found efficacious for testing canine sera. CONCLUSIONS/SIGNIFICANCE: Recombinant salivary proteins of Ph. orientalis, specifically rPorSP24, were shown to successfully substitute SGH in serological experiments to measure exposure of domestic animals to Ph. orientalis, the vector of L. donovani. The results suggest that rPorSP24 might be a suitable antigen for detecting anti-Ph. orientalis antibody-mediated reactions also in other host species.

• MeSH
• antigeny genetika   imunologie   MeSH
• hmotnostní spektrometrie MeSH
• hospodářská zvířata * MeSH
• imunoblotting MeSH
• kousnutí a bodnutí hmyzem diagnóza   MeSH
• kozy MeSH
• ovce MeSH
• protilátky krev   MeSH
• psi MeSH
• Psychodidae genetika   imunologie   MeSH
• rekombinantní proteiny genetika   imunologie   MeSH
• slinné proteiny a peptidy genetika   imunologie   MeSH
• zvířata MeSH
• Check Tag
• psi MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antigeny MeSH
• protilátky MeSH
• rekombinantní proteiny MeSH
• slinné proteiny a peptidy MeSH

The coding sequences of the capsid protein p25 and transmembrane protein of Maedi-Visna virus were amplified using polymerase chain reaction and cloned into the plasmid expression vector pRSET-B. Both DNA constructs expressed proteins tagged with polyhistidine. The recombinant proteins were purified using Ni-NTA agarose and used in immunoblot to detect antibodies against Maedi-Visna virus. A total of 260 ovine serum specimens was analysed. The total number of p25-positive sera was 111 (42.7%). Higher sensitivity was achieved with rTM antigen, which detected antibodies in 118 (45.4%) sera. The combination of both recombinant proteins as antigens resulted in higher sensitivity of serological detection compared to whole virus antigen.

• MeSH
• antigeny virové imunologie   MeSH
• DNA primery MeSH
• elektroforéza v polyakrylamidovém gelu MeSH
• kapsida imunologie   MeSH
• membránové proteiny imunologie   MeSH
• ovce MeSH
• polymerázová řetězová reakce veterinární   MeSH
• prediktivní hodnota testů MeSH
• progresivní intersticiální pneumonie ovcí diagnóza   MeSH
• proteiny virové matrix imunologie   MeSH
• protilátky virové krev   imunologie   MeSH
• rekombinantní proteiny imunologie   MeSH
• senzitivita a specificita MeSH
• virus visna-maedi imunologie   izolace a purifikace   MeSH
• western blotting MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antigeny virové MeSH
• DNA primery MeSH
• membránové proteiny MeSH
• proteiny virové matrix MeSH
• protilátky virové MeSH
• rekombinantní proteiny MeSH

Using Escherichia coli system expressing papilloma virus HPV16 E7MS2 fusion protein as a model system, a novel procedure was applied to solubilize, purify and refold recombinant proteins from E. coli inclusion bodies. The necessity to reactivate proteins at low protein concentrations (owing to their tendency to aggregate at high concentrations) was overcome by solubilization of inclusion bodies in alkaline solution and immobilization of proteins on a strong and resistant anion exchanger. This procedure has an inherent advantage of combining refolding and purification procedures in one step. The solubilization of the fusion protein in an alkaline reagent with the use of an anion exchanger resulted in considerable purification of the recombinant protein at a fairly high concentration. The protein was soluble under mild conditions and reacted with antibodies against the "native" papilloma virus.

• MeSH
• aniontoměniče MeSH
• buněčná inkluze chemie   MeSH
• chromatografie iontoměničová MeSH
• elektroforéza v polyakrylamidovém gelu MeSH
• Escherichia coli chemie   MeSH
• imunoblotting MeSH
• lidé MeSH
• Papillomaviridae genetika   metabolismus   MeSH
• proteiny virové fúze chemie   imunologie   izolace a purifikace   MeSH
• protilátky imunologie   izolace a purifikace   MeSH
• rekombinantní proteiny chemie   imunologie   izolace a purifikace   MeSH
• sbalování proteinů * MeSH
• virové proteiny chemie   imunologie   izolace a purifikace   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• aniontoměniče MeSH
• proteiny virové fúze MeSH
• protilátky MeSH
• rekombinantní proteiny MeSH
• virové proteiny MeSH

Purification of recombinant proteins is often a challenging process involving several chromatographic steps that must be optimized for each target protein. Here, we developed a self-excising module allowing single-step affinity chromatography purification of untagged recombinant proteins. It consists of a 250-residue-long self-processing module of the Neisseria meningitidis FrpC protein with a C-terminal affinity tag. The N terminus of the module is fused to the C terminus of a target protein of interest. Upon binding of the fusion protein to an affinity matrix from cell lysate and washing out contaminating proteins, site-specific cleavage of the Asp-Pro bond linking the target protein to the self-excising module is induced by calcium ions. This results in the release of the target protein with only a single aspartic acid residue added at the C terminus, while the self-excising affinity module remains trapped on the affinity matrix. The system was successfully tested with several target proteins, including glutathione-S-transferase, maltose-binding protein, beta-galactosidase, chloramphenicol acetyltransferase, and adenylate cyclase, and two different affinity tags, chitin-binding domain or poly-His. Moreover, it was demonstrated that it can be applied as an alternative to two currently existing systems, based on the self-splicing intein of Saccharomyces cerevisiae and sortase A of Staphylococcus aureus.

• MeSH
• bakteriální proteiny chemie   MeSH
• chromatografie afinitní metody   MeSH
• kyselina aspartová chemie   MeSH
• membránové proteiny chemie   MeSH
• rekombinantní proteiny chemie   izolace a purifikace   MeSH
• terciární struktura proteinů MeSH
• vápník chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• práce podpořená grantem MeSH
• Názvy látek
• bakteriální proteiny MeSH
• frpC protein, Neisseria meningitidis MeSH Prohlížeč
• kyselina aspartová MeSH
• membránové proteiny MeSH
• rekombinantní proteiny MeSH
• vápník MeSH