Biotechnological Method for Production of Recombinant Peptide Analgesic (Purotoxin-1) from <Emphasis Type="Italic">Geolycosa</Emphasis> sp. Spider Poison

Severe chronic and sometimes incurable diseases are frequently accompanied by a pain syndrome. Purotoxin-1, isolated from the poison of the Central Asian Geolycosa sp. spider and selectively inhibiting the purinergic P2X3 receptor (which is considered as a target for the control of the pain states), is one potentially highly effective drug with an analgesic effect. To produce the recombinant purotoxin-1, we created four genetically engineered constructions with different carrier proteins for the expression in E. coli: pTRX-PT1, pCBD-PT1, pGyrA-PT1, pDnaB-PT1. The construction with mini-intein DnaB from the Synechocystis sp. was the most efficient. Using the E. coli C3030/pDnaB-PT1 producer strain, the laboratory method, based on which a pilot technology of recombinant purotoxin-1 production was developed as a result of optimization and scaling, was created. Six grams of recombinant PT1 preparation with the confirmed pharmacological purity was developed for preclinical trials.     

Biosynthesis of poly(2-hydroxybutyrate-co-lactate) in metabolically engineered <Emphasis Type="Italic">Escherichia coli</Emphasis>

We have previously reported in vivo biosynthesis of polyhydroxyalkanoates containing 2-hydroxyacid monomers such as lactate and 2-hydroxybutyrate in recombinant Escherichia coli strains by the expression of evolved Clostridium propionicum propionyl-CoA transferase (PctCp) and Pseudomonas sp. MBEL 6-19 polyhydroxyalkanoate (PHA) synthase 1 (PhaC1 _Ps6-19). Here, we report the biosynthesis of poly(2-hydroxybutyrate-co-lactate)[P(2HB-co-LA)] by direct fermentation of metabolically engineered E. coli strain. Among E. coli strains WL3110, XL1-Blue, and BL21(DE3), recombinant E. coli XL1-Blue strain expressing PhaC1437 and Pct540 produced P(76.4mol%2HB-co-23.6mol%LA) to the highest content of 88 wt% when it was cultured in a chemically defined medium containing 20 g/L of glucose and 2 g/L of sodium 2-hydroxybutyrate. When recombinant E. coli XL1-Blue strain expressing PhaC1437 and Pct540 was cultured in a chemically defined medium containing 20 g/L of glucose and varying concentration of sodium 2-hydroxybutyrate, 2HB monomer fraction in P(2HB-co-LA) increased proportional to the concentration of sodium 2-hydroxybutyrate added to the culture medium. P(2HB-co-LA)] could also be produced from glucose as a sole carbon source without sodium 2-hydroxybutyrate into the culture medium. Recombinant E. coli XL1-Blue strain expressing the phaC1437, pct540, cimA3.7, and leuBCD genes together with the L. lactis Il1403 panE gene, successfully produced P(23.5mol%2HB-co-76.5mol%LA)] to the polymer content of 19.4 wt% when it cultured in a chemically defined medium containing 20 g/L of glucose. The metabolic engineering strategy reported here should be useful for the production of novel copolymer P(2HB-co-LA)].     

High yield expression in a recombinant <Emphasis Type="Italic">E. coli</Emphasis> of a codon optimized chicken anemia virus capsid protein VP1 useful for vaccine development

Background

Chicken anemia virus (CAV), the causative agent chicken anemia, is the only member of the genus Gyrovirus of the Circoviridae family. CAV is an immune suppressive virus and causes anemia, lymph organ atrophy and immunodeficiency. The production and biochemical characterization of VP1 protein and its use in a subunit vaccine or as part of a diagnostic kit would be useful to CAV infection prevention.

Results

Significantly increased expression of the recombinant full-length VP1 capsid protein from chicken anemia virus was demonstrated using an E. coli expression system. The VP1 gene was cloned into various different expression vectors and then these were expressed in a number of different E. coli strains. The expression of CAV VP1 in E. coli was significantly increased when VP1 was fused with GST protein rather than a His-tag. By optimizing the various rare amino acid codons within the N-terminus of the VP1 protein, the expression level of the VP1 protein in E. coli BL21(DE3)-pLysS was further increased significantly. The highest protein expression level obtained was 17.5 g/L per liter of bacterial culture after induction with 0.1 mM IPTG for 2 h. After purification by GST affinity chromatography, the purified full-length VP1 protein produced in this way was demonstrated to have good antigenicity and was able to be recognized by CAV-positive chicken serum in an ELISA assay.

Conclusions

Purified recombinant VP1 protein with the gene's codons optimized in the N-terminal region has potential as chimeric protein that, when expressed in E. coli, may be useful in the future for the development of subunit vaccines and diagnostic tests.

     

Secretory expression of a novel human spermatozoa antigen in <Emphasis Type="Italic">E</Emphasis>. <Emphasis Type="Italic">coli</Emphasis> and its application to a protein chip

Objective

To produce a recombinant spermatozoa antigen peptide using the E. coli: PhoA system on a protein chip for screening anti-sperm antibodies (ASA).

Results

The purity of the recombinant spermatozoa antigen exceeded 95% after two-step purification, as assessed using SDS-PAGE and HPLC. The diagnostic performance of a protein chip coated with the recombinant antigen peptide was evaluated by examining ASA in 51 infertile patients in comparison with a commercial ELISA kit. The area under the receiver operating characteristic curve (AUC) was 0.944, which indicated that the protein chip coated with recombinant spermatozoa antigen peptide was consistent with ELISA for ASA detection.

Conclusion

A recombinant spermatozoa antigen was expressed in the E. coli PhoA secretory expression system and its potential application for clinical ASA detection was validated.

     

Molecular cloning,biochemical characterization,and antitumor properties of a novel L-asparaginase from <Emphasis Type="Italic">Synechococcus elongatus</Emphasis> PCC6803

L-asparaginase (EC 3.5.1.1), which catalyzes the deamidation of L-asparagine to L-aspartic acid and ammonia, has been widely used as a key therapeutic tool in the treatment of tumors. The current commercially available L-asparaginases, produced from bacteria, have signs of toxicity and hypersensitivity reactions during the course of tumor therapy. Therefore, searching for L-asparaginases with unique biochemical properties and fewer adverse effects was the objective of this work. In this study, cyanobacterial strain Synechococcus elongatus PCC6803 was found as a novel source of L-asparaginase. The L-asparaginase gene coding sequence (gi:939195038) was cloned and expressed in E. coli BL21(DE3), and the recombinant protein (Se.ASPII) was purified by affinity chromatography. The enzyme has high affinity towards Lasparagine and shows very weak affinity towards L-glutamine. The enzymatic properties of the recombinant enzyme were investigated, and the kinetic parameters (K_m, V_max) were measured. The pH and temperature dependence profiles of the novel enzyme were analyzed. The work was extended to measure the antitumor properties of the novel enzyme against different human tumor cell lines.     

A homomeric geranyl diphosphate synthase-encoding gene from <Emphasis Type="Italic">Camptotheca acuminata</Emphasis> and its combinatorial optimization for production of geraniol in <Emphasis Type="Italic">Escherichia coli</Emphasis>

Geranyl diphosphate (GPP), the unique precursor for all monoterpenoids, is biosynthesized from isopentenyl diphosphate and dimethylallyl diphosphate via the head-to-tail condensation reaction catalyzed by GPP synthase (GPPS). Herein a homomeric GPPS from Camptotheca acuminata, a camptothecin-producing plant, was obtained from 5′- and 3′-rapid amplification of cDNA ends and subsequent overlap extension and convenient PCR amplifications. The truncate CaGPPS was introduced to replace ispA of pBbA5c-MevT(CO)-MBIS(CO, ispA), a de novo biosynthetic construct for farnesyl diphosphate generation, and overexpressed in Escherichia coli, together with the truncate geraniol synthase-encoding gene from C. acuminata (tCaGES), to confirm CaGPPS-catalyzed reaction in vivo. A 24.0 ± 1.3 mg L^?1 of geraniol was produced in the recombinant E. coli. The production of GPP was also validated by the direct UPLC-HRMS^E analyses. The tCaGPPS and tCaGES genes with different copy numbers were introduced into E. coli to balance their catalytic potential for high-yield geraniol production. A 1.6-fold increase of geraniol production was obtained when four copies of tCaGPPS and one copy of tCaGES were introduced into E. coli. The following fermentation conditions optimization, including removal of organic layers and addition of new n-decane, led to a 74.6 ± 6.5 mg L^?1 of geraniol production. The present study suggested that the gene copy number optimization, i.e., the ratio of tCaGPPS and tCaGES, plays an important role in geraniol production in the recombinant E. coli. The removal and addition of organic solvent are very useful for sustainable high-yield production of geraniol in the recombinant E. coli in view of that the solubility of geraniol is limited in the fermentation broth and/or n-decane.     

Construction,Expression, and Characterization of Recombinant Pfu DNA Polymerase in <Emphasis Type="Italic">Escherichia coli</Emphasis>

Pfu DNA polymerase (Pfu) is a DNA polymerase isolated from the hyperthermophilic archaeon Pyrococcus furiosus. With its excellent thermostability and high fidelity, Pfu is well known as one of the enzymes widely used in the polymerase chain reaction. In this study, the recombinant plasmid pLysS His₆-tagged Pfu-pET28a was constructed. His-tagged Pfu was expressed in Escherichia coli BL21 (DE3) competent cells and then successfully purified with the ÄKTAprime plus compact one-step purification system by Ni²⁺ chelating affinity chromatography after optimization of the purification conditions. The authenticity of the purified Pfu was further confirmed by peptide mass fingerprinting. A bio-assay indicated that its activity in the polymerase chain reaction was equivalent to that of commercial Pfu and its isoelectric point was found to be between 6.85 and 7.35. These results will be useful for further studies on Pfu and its wide application in the future.     

New recombinant producer of human ω-amidase based on <Emphasis Type="Italic">Escherichia coli</Emphasis>

A new artificial gene encoding human ω-amidase (Nit2) adapted for highly efficient expression in E. coli has been established. A pQE-Nit2 plasmid construct controlled by the T5 promoter has been engineered for its expression. The nit2 gene within the pQE-Nit2 construct has optimized codon usage and an artificial 6His-tag sequence inserted directly after the ATG initiation codon. This tag provides the possibility of single-step purification of a product via metal chelate chromatography. The codon-usage optimization involves the inclusion of several codons of extremely rare occurrence in natural E. coli ORFs within a 30 a.a-long N-terminal region. Other codons included in the N-terminus have moderate occurrence in E. coli. The subsequent sequence of the artificial gene has been composed of the most frequently occurring codons in E. coli. The recombinant producer based on the pQE-Nit2 construct allowed purification of the enzyme with an activity of 6.2 ± 0.2 μmol/min/mg protein, which corresponds to or slightly exceeds the specific activity of rat liver Nit2. The omega-amidase preparation is necessary for the screening of potential inhibitors that can be used as candidate drugs to cure hyperammonemia disorders in liver pathologies and oncological diseases.     

Cloning,Expression, and Characterization of Siamese Crocodile (<Emphasis Type="Italic">Crocodylus siamensis</Emphasis>) Hemoglobin from <Emphasis Type="Italic">Escherichia coli</Emphasis> and <Emphasis Type="Italic">Pichia pastoris</Emphasis>

Recombinant Crocodylus siamensis hemoglobin (cHb) has been constructed and expressed using Escherichia coli as the expression system in conjunction with a trigger factor from the Cold-shock system as the fusion protein. While successful processing as soluble protein in E. coli was achieved, the net yields of active protein from downstream purification processes remained still unsatisfactory. In this study, cHb was constructed and expressed in the eukaryotic expression system Pichia pastoris. The results showed that cHb was excreted from P. pastoris as a soluble protein after 72 h at 25 °C. The amino acid sequence of recombinant cHb was confirmed using LC–MS/MS. Indeed, the characteristic of Hb was investigated by external heme incorporation. The UV–Vis profile showed a specific pattern of the absorption at 415 nm, indicating the recombinant cHb was formed complex with heme, resulting in active oxyhemoglobin (OxyHb). This result suggests that the heme molecules were fully combined with heme binding site of the recombinant cHb, thus producing characteristic red color for the OxyHb at 540 and 580 nm. The results revealed that the recombinant cHb was prosperously produced in P. pastoris and exhibited a property as protein–ligand binding. Thus, our work described herein offers a great potential to be applied for further studies of heme-containing protein expression. It represents further pleasing option for protein production and purification on a large scale, which is important for determination and characterization of the authenticity features of cHb proteins.     

Bioresolution of racemic phenyl glycidyl ether by a putative recombinant epoxide hydrolase from <Emphasis Type="Italic">Streptomyces griseus</Emphasis> NBRC 13350

In order to produce enantiomerically pure epoxides for the synthesis of value-added chemicals, a novel putative epoxide hydrolase (EH) sgeh was cloned and overexpressed in pET28a/Escherichia coli BL21(DE3). The 1047 bp sgeh gene was mined from Streptomyces griseus NBRC 13350 genome sequence. The recombinant hexahistidyl-tagged SGEH was purified (16.6-fold) by immobilized metal-affinity chromatography, with 90% yield as a homodimer of 100 kDa. The recombinant E. coli whole cells overexpressing SGEH could kinetically resolve racemic phenyl glycidyl ether (PGE) into (R)-PGE with 98% ee, 40% yield, and enantiomeric ratio (E) of 20. This was achieved under the optimized reaction conditions i.e. cell/substrate ratio of 20:1 (w/w) at pH 7.5 and 20?°C in 10% (v/v) dimethylformamide (DMF) in a 10 h reaction. 99% enantiopure (R)-PGE was obtained when the reaction time was prolonged to 12 h with a yield of 34%. In conclusion, an economically viable and environment friendly green process for the production of enantiopure (R)-PGE was developed by using wet cells of E. coli expressing recombinant SGEH.     

Stability,oviposition attraction,and larvicidal activity of binary toxin from <Emphasis Type="Italic">Bacillus sphaericus</Emphasis> expressed in <Emphasis Type="Italic">Escherichia coli</Emphasis>

Bacillus sphaericus produces a two-chain binary toxin composed of BinA (42 kDa) and BinB (51 kDa), which are deposited as parasporal crystals during sporulation. The toxin is highly active against Culex larvae and Aedes and Anopheles mosquitoes, which are the principal vectors for the transmission of malaria, yellow fever, encephalitis, and dengue. The use of B. sphaericus and Bacillus thuringiensis in mosquito control programs is limited by their sedimentation in still water. In this study, the binA and binB genes were cloned and the recombinant BinAB protein was expressed in three strains of Escherichia coli. These recombinant strains were used in a toxicity assay against Culex quinquefasciatus larvae. The highest expression level was achieved when both proteins were expressed in a single operon construct. The BinAB protein expressed in the E. coli Arctic strain showed higher larvicidal activity than either of the recombinant proteins from the E. coli Ril or pLysS strains. Furthermore, it had the highest oviposition attraction (49.1%, P?相似文献   

Enhancement of crystallinity of cellulose produced by <Emphasis Type="Italic">Escherichia coli</Emphasis> through heterologous expression of <Emphasis Type="Italic">bcsD</Emphasis> gene from <Emphasis Type="Italic">Gluconacetobacter xylinus</Emphasis>

Objectives

To evaluate the crystallinity index of the cellulose produced by Escherichia coli Nissle 1917 after heterologous expression of the cellulose synthase subunit D (bcsD) gene of Gluconacetobacter xylinus BPR2001.

Results

The bcsD gene of G. xylinus BPR2001 was expressed in E. coli and its protein product was visualized using SDS-PAGE. FTIR analysis showed that the crystallinity index of the cellulose produced by the recombinants was 0.84, which is 17% more than that of the wild type strain. The increased crystallinity index was also confirmed by X-ray diffraction analysis. The cellulose content was not changed significantly after over-expressing the bcsD.

Conclusion

The bcsD gene can improve the crystalline structure of the bacterial cellulose but there is not any significant difference between the amounts of cellulose produced by the recombinant and wild type E. coli Nissle 1917.

     

Improved Tolerance of <Emphasis Type="Italic">Escherichia coli</Emphasis> to Propionic Acid by Overexpression of Sigma Factor RpoS

Propionic acid (PA) is an economically important compound, but large-scale microbial production of PA confronts obstacle such as acid stress on microbial cells. Here, we show that overexpressing sigma factor RpoS improves the acid tolerance of Escherichia coli. Four genes including rpoS, fur, pgi and dnaK (encoding RNA polymerase sigma factor, ferric uptake regulator, phosphoglucoisomerase, and chaperone, respectively) were independently overexpressed in E. coli. The recombinant E. coli overexpressing rpoS showed the highest PA tolerance. This strain could grow in M9 medium at pH 4.62, whereas wild type E. coli survived only at pHs above 5.12. Moreover, in the shake-flask cultivation, the E. coli strain overexpressing rpoS grew faster than wild type. Notably, the minimum inhibitory concentration of PA for this recombinant strain was 7.81 mg/mL, which was 2-fold higher in comparison with wild type. Overall these results indicated that overexpression of sigma factor rpoS significantly enhanced E. coli tolerance to PA.     

Purification of active recombinant human histone deacetylase 1 (HDAC1) overexpressed in <Emphasis Type="Italic">Escherichia coli</Emphasis>

Objective

We attempted to overexpress Human Histone Deacetylase 1 (HDAC1) in Escherichia coli.

Results

A synthetic gene coding for HDAC1, and optimised for E. coli codon usage, was cloned into pBADHisB, generating pBAD-rHDAC1. This construct was used to transform E. coli TOP10, and the target protein was overexpressed and partially purified. According to its elution volume from a Superdex 200 column, the partially purified rHDAC1 was obtained in aggregated form, i.e., as an octamer. The dissociation of octameric HDAC1 was tested using several agents, among which sodium dodecyl sulfate was competent in partially dissociating rHDAC1 aggregates. When the enzyme activity was tested in vitro using ³H-acetyl-labelled histones both protein samples, aggregated and dissociated, were active. Hence, our results suggest that E. coli represents an alternative system for the production of the recombinant HDAC1.

Conclusions

We described a procedure for the overexpression in E. coli of recombinant HDAC1, the purification of which in active form can be successfully performed, although yielding an octameric aggregate.

     

Recombinant oxyntomodulin

An artificial gene encoding oxyntomodulin was obtained using chemical and enzymatic methods and cloned into Escherichia coli. A recombinant plasmid was constructed containing a hybrid oxyntomodulin gene and Ssp dnaB intein from Synechocystis sp. The expression of the resulting hybrid gene in E. coli, its properties, and the conditions of its autocatalytic cleavage to oxyntomodulin were studied.     

Gene Cloning,Expression, and Properties of a Fibrinolytic Enzyme Secreted by <Emphasis Type="Italic">Bacillus pumilus</Emphasis> BS15 Isolated from Gul (Oyster) Jeotgal

A Bacillus strain, BS15, showing strong fibrinolytic activity, antibacterial activity, and salt tolerance was isolated from gul (oyster) jeotgal, a Korean fermented sea food. BS15 was identified as B. pumilus. B. pumilus BS15 was able to grow in LB broth with 18% (w/v) NaCl. When culture supernatant was analyzed by SDS-PAGE, 22, 27, 35, and 60 kDa proteins were observed. The 27 kDa protein was determined to be major fibrinolytic enzyme by fibrin zymography. The gene (aprEBS15) was cloned in pHY300PLK, a Bacillus-E. coli shuttle vector. A B. subtilis transformant (TF) harboring pHYBS15 showed higher fibrinolytic activity than B. pumilus BS15, and produced the same 27 kDa protein. aprEBS15 was overexpressed in E. coli BL21 (DE3), and recombinant enzyme (AprEBS15) was purified. The optimum pH and temperature of AprEBS15 were pH 8.0 and 40°C, respectively. Km and Vmax values were 0.26 mM and 21.88 µmol/L/min, respectively. B. pumilus BS15 can be used as a starter for jeotgals and other fermented foods with high salinities.     

Biochemical Properties and Mechanism of Action of Enterocin LD3 Purified from <Emphasis Type="Italic">Enterococcus hirae</Emphasis> LD3

Enterocin LD3 was purified using activity-guided multistep chromatography techniques such as cation-exchange and gel-filtration chromatography. The preparation’s purity was tested using reverse-phase ultra-performance liquid chromatography. The specific activity was tested to be 187.5 AU µg^?1 with 13-fold purification. Purified enterocin LD3 was heat stable up to 121 °C (at 15 psi pressure) and pH 2–6. The activity was lost in the presence of papain, reduced by proteinase K, pepsin and trypsin, but was unaffected by amylase and lipase, suggesting proteinaceous nature of the compound and no role of carbohydrate and lipid moieties in the activity. MALDI-TOF/MS analysis of purified enterocin LD3 resolved m/z 4114.6, and N-terminal amino acid sequence was found to be H₂NQGGQANQ–COOH suggesting a new bacteriocin. Dissipation of membrane potential, loss of internal ATP and bactericidal effect were recorded when indicator strain Micrococcus luteus was treated with enterocin LD3. It inhibited Gram-positive and Gram-negative bacteria including human pathogens such as Staphylococcus aureus, Pseudomonas fluorescens, Pseudomonas aeruginosa, Salmonella typhi, Shigella flexneri, Listeria monocytogenes, Escherichia coli O157:H7, E. coli (urogenic, a clinical isolate) and Vibrio sp. These properties of purified enterocin LD3 suggest its applications as a food biopreservative and as an alternative to clinical antibiotics.     

Chaperone-assisted expression of KfiC glucuronyltransferase from <Emphasis Type="Italic">Escherichia coli</Emphasis> K5 leads to heparosan production in <Emphasis Type="Italic">Escherichia coli</Emphasis> BL21 in absence of the stabilisator KfiB

The heparosan synthase of Escherichia coli K5 is composed of the glycosyltransferases KfiA and KfiC which synthesize the polysaccharide heparosan (N-acetylheparosan). A third protein, KfiB, is required to stabilize the KfiAC complex in the bacteria and to transport this complex to the inner membrane where the initiation of polymerization occurs. In this report, we fused KfiC with the E. coli trigger factor (TF) to stabilize KfiC, thus activating the enzyme in the absence of KfiB. Different recombinant plasmids were constructed to compare the impact of the presence or absence of KfiB and the presence of the trigger factor as a fusion protein. Several E. coli BL21-derived strains were transformed with recombinant plasmids and cultivated in fed-batch conditions on minimal medium. The bTCA strain overexpressing fused TF-KfiC together with KfiA and KfiD, but lacking KfiB produced 1.5 g/L of total heparosan after 24 h of fed-batch cultivation. This heparosan was essentially intracellular early in the culture, providing evidence that KfiB primarily plays a role in the exportation process. However, over time, heparosan became mostly extracellular, likely due to passive diffusion or partial cell disruption upon product accumulation.