His-tagged Protein Research Articles

Overexpression of LeNHX4 improved yield, fruit quality and salt tolerance in tomato plants (Solanum lycopersicum L.).

The function of the tomato K+, Na+/H+ antiporter LeNHX4 has been analyzed using 35S-driven gene construct for overexpressing a histagged LeNHX4 protein in Solanum lycopersicum L. Compared to wild-type plants, the expression of LeNHX4 was enhanced in most of plants transformed with a gene construct for LeNHX4 overexpression although some plants showed a decreased LeNHX4 expression. Overexpression of LeNHX4 was associated to an increased fruit size while silencing of this gene was related to a decreased fruit size. We have investigated the effect of LeNHX4 overexpression on fruit production and quality and we have also evaluated salt tolerance in two different overexpression lines by measuring proline, protein and glucose concentrations in tomato leaves grown either under control (0mM NaCl) or saline (125mM NaCl) conditions. Plants overexpressing LeNHX4 showed a higher amount of fruits than WT plants and accumulated higher contents of sugars and cations (Na+ and K+). The application of 125mM NaCl, affected negatively fruit production and quality of WT plants. However the transgenic lines overexpressing LeNXH4 increased fruit quality and yield. In relation to salt tolerance, overexpression lines showed higher levels of leaf proline, glucose and proteins under NaCl treatment. The overexpression of LeNHX4 in tomato plants, improved salinity tolerance and increased fruit yield and quality under both normal and salinity stress conditions.

Electrochemical Release of His-Tagged Proteins By Destruction of NTA-Cu(II)-Protein Complex

Stimuli responsive release of biomolecules from surfaces such as gold and carbon is gaining importance for past couple of decades due to its application in biomedical field. Electrochemically induced release of biomolecules from the surfaces is one of such techniques. The simplicity of the electrochemical techniques brings-in a wide opportunity for loading and releasing biomolecules from the electrode surfaces. Here-in we report the loading and electrochemical release of His-tagged proteins from the electrode surfaces such as gold and graphite1. Reversible chelation of His-tagged proteins on Ni-NTA surfaces is studied for decades. Competing ligands such as imidazole and EDTA are used for releasing the His-tagged proteins from the Ni-NTA surfaces. However, switching the metal to Cu(II) instead of Ni(II) brings an excellent opportunity for releasing the His-tagged proteins by the reduction of Cu(II). The affinity of Cu(I) towards complexation with NTA and His-tag is substantially lower than Cu(II) which facilitates the release of the protein. Cu-NTA crafted graphite and gold electrodes were used for the coordinative loading of His-tagged proteins and electrochemical reduction of metal ion for the release of the proteins from the surface. In this study a redox mediator coupled model peptide (ferrocene-hexahistidine) and a model recombinant protein (containing His-tag) “Protein A” were used as examples for loading and electrochemical release.ǂ These authors equally contributed to the work Reference: 1. Bellare, M.; Kadambar, V. K.; Bollella, P.; Gamella, M.; Katz, E. and Melman, A; Electrochemical release of His-tagged proteins by destruction of NTA-Cu(II)-protein complex; Electroanalysis 2019, accepted manuscript.

Affinity Based Nano-Magnetic Particles for Purification of Recombinant Proteins in Form of Inclusion Body

Background:Protein purification is the most complicated issue in the downstream processes of recombinant protein production; therefore, improved selective purification methods are important. Affinity-based protein purification method using His-tag and Ni-NTA resins is one of the most common strategies. MNPs can be used as a beneficial alternative for Ni-NTA resins. However, there is no data on the capability of MNPs for protein purification from inclusion bodies; this issue is studied here. Methods:Recombinant His-tagged proteins of EGFP-His and SK-His were expressed in E. coli BL-21 (DE3) in soluble and inclusion body forms, respectively. MNPs including Fe3O4 magnetic core, SiO2 shell, and Ni2+ on the surface were synthesized by sol-gel and hydrothermal reactions and then characterized by XRD, VSM, and SEM imaging. Both synthesized Fe3O4@NiSiO3 and Fe3O4@NixSiOy MNPs were employed to purify EGEP-His and SK-His under native and denaturing conditions, respectively. The quantity and purity of purified proteins were analyzed by micro-Bradford assay and SDS-PAGE, respectively. Results:Both synthesized MNPs were spherical and well-dispersed with the size ranging from 290 to 415 nm. Synthesized MNPs contained Fe3O4, SiO2 shell, and Ni2+ on their structures with suitable magnetization properties. Using Fe3O4@NiSiO3 and Fe3O4@NixSiOy yielded 192 and 188 µg/mg of SK-His, as compared to 207 and 195 µg/mg of EGFP-His, respectively. Conclusion:MNPs containing magnetic Fe3O4 core, SiO2 shell, and Ni2+on their surface are versatile alternatives for Ni-NTA resins in protein purification for proteins expressed in both soluble and inclusion body forms.

Construction of the Nickel Oxide Nanocoral Structure on Microscope Slides for Total Self-Assembly-Oriented Probe Immobilization and Signal Enhancement.

Proper orientation of probes and the binding capacity of surfaces will determine the performance of bio-applications. It has been reported that immobilizing through bio-/chemical affinity is an efficient but gentle strategy to solve the above-mentioned issue. Herein, we introduce a total self-assembly approach via the strong affinity of nickel oxide (NiO) to the polyhistidine-tag (His-tag). It allows the efficient immobilizing His-tagged proteins with orientation. Furthermore, we find that the nanocoral structure can be formed after applying rapid thermal annealing at 1100 °C, which could increase the His-tagged protein binding capacity efficiently by the enhanced surface-to-volume ratio. Lastly, we demonstrate the NiO thin film with the nanocoral structure, which has great potential for universal biosensing with a wide range of biomolecules, including DNA, protein, and bacteria. Through His-tagged monomer streptavidin (His6-mSA) or His-tagged protein G (His6-protein G), the biotinylated DNA or antibody could be immobilized with proper orientation on the surface consequently to complete a sensitive biomolecule detection. Moreover, the NiO nanocoral structure has the advantages of high hydrophilicity, transmittance, and pH stability that are promising to develop into several kinds of bio-applications in the near future.

Self-assembly of robust gold nanoparticle monolayer architectures for quantitative protein interaction analysis by LSPR spectroscopy

Localized surface plasmon resonance (LSPR) detection offers highly sensitive label-free detection of biomolecular interactions. Simple and robust surface architectures compatible with real-time detection in a flow-through system are required for broad application in quantitative interaction analysis. Here, we established self-assembly of a functionalized gold nanoparticle (AuNP) monolayer on a glass substrate for stable, yet reversible immobilization of Histidine-tagged proteins. To this end, one-step coating of glass substrates with poly-L-lysine graft poly(ethylene glycol) functionalized with ortho-pyridyl disulfide (PLL-PEG-OPSS) was employed as a reactive, yet biocompatible monolayer to self-assemble AuNP into a LSPR active monolayer. Site-specific, reversible immobilization of His-tagged proteins was accomplished by coating the AuNP monolayer with tris-nitrilotriacetic acid (trisNTA) PEG disulfide. LSPR spectroscopy detection of protein binding on these biocompatible functionalized AuNP monolayers confirms high stability under various harsh analytical conditions. These features were successfully employed to demonstrate unbiased kinetic analysis of cytokine-receptor interactions.Graphical abstract

Ultrafast in-gel detection by fluorescent super-chelator probes with HisQuick-PAGE

Polyacrylamide gel electrophoresis (PAGE) and immunoblotting (Western blotting) are the most common methods in life science. In conjunction with these methods, the polyhistidine-tag has proven to be a superb fusion tag for protein purification as well as specific protein detection by immunoblotting, which led to a vast amount of commercially available antibodies. Nevertheless, antibody batch-to-batch variations and nonspecific binding complicate the laborious procedure. The interaction principle applied for His-tagged protein purification by metal-affinity chromatography using N-nitrilotriacetic acid (NTA) was employed to develop small high-affinity lock-and-key molecules coupled to a fluorophore. These multivalent NTA probes allow specific detection of His-tagged proteins by fluorescence. Here, we report on HisQuick-PAGE as a fast and versatile immunoblot alternative, using such high-affinity fluorescent super-chelator probes. The procedure allows direct, fast, and ultra-sensitive in-gel detection and analysis of soluble proteins as well as intact membrane protein complexes and macromolecular ribonucleoprotein particles.

Non-negligible factors in studying the ApoM-S1P axis using EA.hy926 cells.

BackgroundThe apolipoprotein M (ApoM)-sphingosine-1-phosphate (S1P) axis was recently identified, and research into its function has received increasing attention. However, there are some factors which might influence the results of studies into the function of the ApoM-S1P axis using the EA.hy926 cells. This study investigated related factors, including coagulation factor VIII (FVIII), ApoM, S1P receptor subtypes (S1PRs), C-myc-tagged, and His-tagged proteins in EA.hy926 cells, as well as the effects of ApoM overexpression on S1PRs.MethodsThe expression of FVIII, ApoM, S1PRs, C-myc, and His-tagged proteins in EA.hy926 cells was investigated through cellular immunofluorescence. EA.hy926 cells were infected with lentiviruses carrying (OE group) or lacking (NC group) the ApoM gene sequence. A stable cell line expressing ApoM was obtained, and the expression of ApoM mRNA was detected through single tube duplex fluorescence reverse transcription quantitative polymerase chain reaction (RT-qPCR). S1PRs expression was detected by RT-qPCR and Western blotting.ResultsThe results showed that EA.hy926 cells expressed FVIII, ApoM, C-myc-tagged, and His-tagged proteins. Moreover, they highly expressed S1PR1, slightly expressed S1PR3, weakly expressed S1PR2, and did not express S1PR4 and S1PR5. ApoM overexpression significantly increased S1PR1 mRNA and protein expression but did not affect the expression of S1PR3. EA.hy926 cells expressed FVIII, suggesting the cell line possesses endothelial cell characteristics and could be used for in vitro studies of the ApoM-S1P axis.ConclusionsEA.hy926 cell line is suitable for investigation of the ApoM-S1P axis in vitro. However, Since EA.hy926 cells expressed endogenous ApoM, C-myc and His tagged proteins, the exogenous recombinant ApoM should not be labeled with C-myc and His tags for distinguishing from endogenous ApoM. In addition, overexpression of ApoM should be considered to significantly increase the expression of S1PR1 when studying the APOM-S1P axis.

The Streptomyces coelicolor Small ORF trpM Stimulates Growth and Morphological Development and Exerts Opposite Effects on Actinorhodin and Calcium-Dependent Antibiotic Production.

In actinomycetes, antibiotic production is often associated with a morpho-physiological differentiation program that is regulated by complex molecular and metabolic networks. Many aspects of these regulatory circuits have been already elucidated and many others still deserve further investigations. In this regard, the possible role of many small open reading frames (smORFs) in actinomycete morpho-physiological differentiation is still elusive. In Streptomyces coelicolor, inactivation of the smORF trpM (SCO2038) – whose product modulates L-tryptophan biosynthesis – impairs production of antibiotics and morphological differentiation. Indeed, it was demonstrated that TrpM is able to interact with PepA (SCO2179), a putative cytosol aminopeptidase playing a key role in antibiotic production and sporulation. In this work, a S. coelicolor trpM knock-in (Sco-trpMKI) mutant strain was generated by cloning trpM into overexpressing vector to further investigate the role of trpM in actinomycete growth and morpho-physiological differentiation. Results highlighted that trpM: (i) stimulates growth and actinorhodin (ACT) production; (ii) decreases calcium-dependent antibiotic (CDA) production; (iii) has no effect on undecylprodigiosin production. Metabolic pathways influenced by trpM knock-in were investigated by combining two-difference in gel electrophoresis/nanoliquid chromatography coupled to electrospray linear ion trap tandem mass spectrometry (2D-DIGE/nanoLC-ESI-LIT-MS/MS) and by LC-ESI-MS/MS procedures, respectively. These analyses demonstrated that over-expression of trpM causes an over-representation of factors involved in protein synthesis and nucleotide metabolism as well as a down-representation of proteins involved in central carbon and amino acid metabolism. At the metabolic level, this corresponded to a differential accumulation pattern of different amino acids – including aromatic ones but tryptophan – and central carbon intermediates. PepA was also down-represented in Sco-trpMKI. The latter was produced as recombinant His-tagged protein and was originally proven having the predicted aminopeptidase activity. Altogether, these results highlight the stimulatory effect of trpM in S. coelicolor growth and ACT biosynthesis, which are elicited through the modulation of various metabolic pathways and PepA representation, further confirming the complexity of regulatory networks that control antibiotic production in actinomycetes.

Controlled division of cell-sized vesicles by low densities of membrane-bound proteins

The proliferation of life on earth is based on the ability of single cells to divide into two daughter cells. During cell division, the plasma membrane undergoes a series of morphological transformations which ultimately lead to membrane fission. Here, we show that analogous remodeling processes can be induced by low densities of proteins bound to the membranes of cell-sized lipid vesicles. Using His-tagged fluorescent proteins, we are able to precisely control the spontaneous curvature of the vesicle membranes. By fine-tuning this curvature, we obtain dumbbell-shaped vesicles with closed membrane necks as well as neck fission and complete vesicle division. Our results demonstrate that the spontaneous curvature generates constriction forces around the membrane necks and that these forces can easily cover the force range found in vivo. Our approach involves only one species of membrane-bound proteins at low densities, thereby providing a simple and extendible module for bottom-up synthetic biology.

AD946 and AF371 antibodies recognize a His-tagged recombinant protein by immunofluorescence

AD946 and AF371 antibodies against the His tag recognize a His-tagged human TAC protein by immunofluorescence in paraformaldehyde-fixed HeLa cells.

Skimmed milk as an alternative for IPTG in induction of recombinant protein expression

Cost-effectiveness is an important issue in biotechnological manufacturing industry and using alternative cheap materials with the same benefits has been noticed in most literatures. Isopropyl β-d-1-thiogalactopyranoside (IPTG), a well-known chemical element for induction of protein expression, has several disadvantages such as high expense and toxicity. In this study, we aimed to introduce skimmed milk as an alternative material for protein expression by induction of lac operon. In this way, Escherichia coli BL21 (DE3) bacteria were induced using 1 mM IPTG or 1.0% (w/v) skimmed milk. Protein purification was performed using Ni-NTA (nickel-nitrilotriacetic acid) for His-tagged recombinant proteins and protein purity was evaluated by SDS-PAGE. Results showed high level of recombinant protein expression using skimmed milk, and interestingly, the growth rate of bacteria improved. Our findings suggested that skimmed milk can be a suitable alternative for induction of recombinant protein expression, which has advantages such as more availability and affordability, in comparison to IPTG supplementation.

Probing Protein-Protein Interactions with Label-Free Mass Spectrometry Quantification in Combination with Affinity Purification by Spin-Tip Affinity Columns.

We describe an affinity purification-mass spectrometry (AP-MS) method for probing the interactome of a special targeting protein. The AP was implemented with monolithic micro immobilized metal ion affinity chromatography columns (m-IMAC) which were prepared by photoinitiated polymerization in the tip of a pipet (spin-tip columns). The recombinant His6-tagged protein (bait protein) was reversibly immobilized on the affinity column through the chelating group nitrilotriacetic acid (NTA)-Ni2+. The bait protein and its interacting partners can be easily eluted from the affinity matrix. The pulled-down cellular proteins were then analyzed with label-free quantitative proteomics. We used this method for probing the interactome concerning the GOLD (Golgi dynamics) domain of the autophagy-associated adaptor protein FYCO1. Totally, 96 proteins including seven literature-reported FYCO1-associating proteins were identified. Among them CCZ1 and MON1A were further biochemically validated, and the direct interaction between the FYCO1 GOLD domain with CCZ1 was confirmed by co-immunoprecipitation experiments.

Reliable method for high quality His-tagged and untagged E. coli phosphoribosyl phosphate synthase (Prs) purification

Prs (phosphoribosyl pyrophosphate synthase) is a broadly conserved protein that synthesises 5-phosphoribosyl 1-pyrophospate (PRPP); a substrate for biosynthesis of at least 10 enzymatic pathways including biosynthesis of DNA building blocks - purines and pyrimidines. In Escherichia coli, it is a protein of homo-hexameric quaternary structure, which can be challenging to work with, due to frequent aggregation and activity loss. Several studies showed brief purification protocols for various bacterial PRPP synthases, in most cases involving ammonium sulfate precipitation.Here, we provide a protocol for expression of E. coli Prs protein in Rosetta (DE3) and BL21 (DE3) pLysE strains and a detailed method for His-Prs and untagged Prs purification on nickel affinity chromatography columns. This protocol allows purification of proteins with high yield, purity and activity. We report here N-terminally His-tagged protein fusions, stable and active, providing that the temperature around 20 °C is maintained at all stages, including centrifugation. Moreover, we successfully applied this method to purify two enzyme variants with K194A and G9S alterations. The K194A mutation in conserved lysine residue results in protein variant unable to synthetize PRPP, while the G9S alteration originates from prs-2 allele variant which was previously related to thermo-sensitive growth. His-PrsG9S protein purified here, exhibited comparable activity as previously observed in-vivo suggesting the proteins purified with our protocol resemble their physiological state.The protocol for Prs purification showed here indicates guidance to improve stability and quality of the protein and to ensure more reliable results in further assays in-vitro.

Silica microspheres functionalized with the iminodiacetic acid/copper(II) complex as a peroxidase mimic for use in metal affinity chromatography-based colorimetric determination of histidine-tagged proteins.

Monodisperse porous silica microspheres were functionalized with the iminodiacetic acid/copper(II) complex and then evaluated as a group-specific peroxidase-mimicking nanozyme for colorimetric determination of histidine-tagged (His-tagged) proteins. The green fluorescent protein (GFP) was selected as a typical His-tagged protein. The specificity for GFP and the peroxidase-like activity for the selected substrate were obtained by immobilizing the complex on the porous microspheres. The modified microspheres were also evaluated as a group specific immobilized metal affinity chromatography (IMAC) sorbent for the purification of GFP from Escherichia coli extract. The peroxidase-like activity of the microspheres was inhibited by the GFP adsorbed onto the microspheres due to the interaction of His-tagged protein with the immobilized Cu(II) complex. Ortho-phenylenediamine is used as a substrate for the enzyme mimic. The photometric response (measured at 416nm) is linear in the 9.0-92μg·mL-1 GFP concentration range in E. coli lysate. The limit of detection is 6.9μg·mL-1. Graphical abstractSchematic representation of metal affinity chromatography-based colorimetric determination of histidine-tagged proteins using silica microspheres functionalized with iminodiacteic acid/copper (II) complex as a peroxidase mimic.

Development of a new and simple method for the detection of histidine-tagged proteins based on thionine-chitosan/gold nanoparticles/horseradish peroxidase.

In the current study, an electrochemical biosensing signal amplification system was utilized with thionine-chitosan-gold nanoparticles (Chit-GNPs) that absorbed horseradish peroxidase (HRP) and anti-His tagged protein monoclonal antibody derived from Balb/c mice. In addition, transmission electron microscopy (TEM) was used to characterize the nanogold solution and atomic force microscopy (AFM) was used to characterize the sensor assembly. To evaluate the quality of the immunosensor, the amperometric I-t curve method was applied to determine His-IL23 in PBS. The results indicated that the response current exhibited an optimal linear correlation with the His-IL23 concentration that ranged from 0.01 to 103ng/ml. The lowest detection limit was noted at 3.3pg/ml (S/N = 3). The linear equation was deduced as follows: △I = 0.02lgC + 0.037 (R2 = 0.9628). Moreover, it was validated with high sensitivity, reproducibility and rapid response. Apparently, the immunosensor may be a very useful tool for the detection and quantification of His-tagged proteins. In addition, the signal amplification system can be used for the preparation of other immunosensors and to assist in bioassays.

Cross-kingdom mimicry of the receptor signaling and leukocyte recruitment activity of a human cytokine by its plant orthologs

Cross-kingdom mimicry of the receptor signaling and leukocyte recruitment activity of a human cytokine by its plant orthologs

Growth promotion in Corynebacterium glutamicum by overexpression of the NCgl2986 gene encoding a protein homologous to peptidoglycan amidases.

We previously reported the extracellular production of antibody fragment Fab by Corynebacterium glutamicum. In the course of searching for genes which improve the secretion efficiency of Fab, we coincidentally found that the final growth increased significantly when the NCgl2986 gene encoding an amidase-like protein was overexpressed. This effect was observed when cells were grown on the production medium MMTG, which contains high concentrations of glucose and neutralizing agent CaCO3, but not on MMTG without CaCO3 or Lennox medium. Not only turbidity but also dry cell weight was increased by NCgl2986 overexpression, although the growth rate was not affected. It was recently reported that the Mycobacterium tuberculosis homolog Rv3915 functions as an activator of MurA protein, which catalyzes the initial step of peptidoglycan synthesis. Growth promotion was also observed when the MurA protein was overproduced. His-tagged NCgl2986 protein was purified, but its peptidoglycan hydrolyzing activity could not be detected. These results suggest that NCgl2986 promotes cell growth by activating the peptidoglycan synthetic pathway.

Aptamers vs. antibodies as capture probes in optical porous silicon biosensors.

Over the past decade aptamers have emerged as a promising class of bioreceptors for biosensing applications with significant advantages over conventional antibodies. However, experimental studies comparing aptasensors and immunosensors, under equivalent conditions, are limited and the results are inconclusive, in terms of benefits and limitations of each bioreceptor type. In the present work, the performance of aptamer and antibody bioreceptors for the detection of a his-tagged protein, used as a model target, is compared. The bioreceptors are immobilized onto a nanostructured porous silicon (PSi) thin film, used as the optical transducer, and the target protein is detected in a real-time and label-free format by reflective interferometric Fourier transform spectroscopy. For the antibodies, random-oriented immobilization onto the PSi nanostructure results in a poor biosensing performance. Contrary, Fc-oriented immobilization of the antibodies shows a similar biosensing performance to that exhibited by the aptamer-based biosensor, in terms of binding rate, dynamic detection range, limit of detection and selectivity. The aptasensor outperforms in terms of its reusability and storability, while the immunosensor could not be regenerated for subsequent experiments.

A polycarboxylic chelating ligand for efficient resin purification of His-tagged proteins expressed in mammalian systems

We describe the synthesis of a novel polyamino polycarboxylic ligand, its ability to coordinate metal-ions and attachment to a solid support designed for protein purification through Immobilised Metal-ion Affinity Chromatography (IMAC). The resin was found to be highly efficient for purification of His-tagged HCV E2 glycoproteins expressed in 293T mammalian cells.

Биосинтез и секреция сериновой пептидазы SerP38 Tenebrio molitor в дрожжах Komagataella kurtzmanii

A strain of the Komagataella kurtzmanii yeast, a producer of recombinant peptidase SerP38 from the yellow mealworm Tenebrio molitor, has been obtained. The level of the pro-enzyme secretion was 20-50 mg/L. It was shown that, during secretion in yeast, the target His6-tagged protein was produced in two forms. One of them was a monomer that was efficiently purified by Ni-NTA chromatography and then activated with trypsin. Another form accumulated in the culture medium as oligomers prone to aggregation in the presence of Ni2+ ions and was not activated by trypsin treatment. Aggregation is likely the result of incorrect folding of the polypeptide chain. Tenebrio molitor, S1 family serine peptidase, SerP38, yeast, Komagataella kurtzmanii, ion-dependent aggregation