Co-expression, purification and bioassay of three avian viral antigens / 生物工程学报

To achieve uniform soluble expression of multiple proteins in the same Escherichia coli strain, and simplify the process steps of antigen production in genetic engineering subunit multivalent vaccine, we co-expressed three avian virus proteins including the fowl adenovirus serotype 4 (FAdV-4) Fiber-2 protein, infectious bursal disease virus (IBDV) VP2 protein and egg-drop syndrome virus (EDSV) Fiber protein in E. coli BL21(DE3) cells after optimization of gene codon, promoter, and tandem expression order. The purified proteins were analyzed by Western blotting and agar gel precipitation (AGP). The content of the three proteins were well-proportioned after co-expression and the purity of the purified proteins were more than 80%. Western blotting analysis and AGP experiment results show that all the three co-expression proteins had immunoreactivity and antigenicity. It is the first time to achieve the three different avian virus antigens co-expression and co-purification, which simplified the process of antigen production and laid a foundation for the development of genetic engineering subunit multivalent vaccine.

Expression Enhancement Of Trastuzumab In Cho Cells Using Codon Optimization And Promoter Selection For Mammalian Expression Vector

Trastuzumab is recombinant humanized monoclonal IgG antibody used in the treatment of metastatic breast cancer. It blocks the overexpression of tyrosine kinase Her 2 family receptors and downregulation of pathways. Genetic optimizations like gene optimization and expression vector optimization are the key elements to enhance monoclonal antibody expression. Expression vector optimization includes major parameters like selection of right promoters, poly A tail selection of genome integrating elements. Codon optimization is gene designing approach without affecting the amino acid sequence of the protein. Current research work involves development of codon optimization algorithm for trastuzumab heavy and light chain gene and comparative analysis of expression in different vectors.

Application of codon optimization strategy in heterologous protein expression / 生物工程学报

Enzymes are widely used in medical and biopharmaceuticals. They can be used not only for various disease treatments, but also clinical diagnosis. The use of microorganisms to express heterologous proteins has become the easiest and fastest way to obtain enzymes. In order to obtain high concentration and high-quality heterologous proteins, a common method is codon optimization of gene sequences. The traditional codon optimization strategy is mainly based on codon bias and GC content, ignoring complex and varied factors such as translational dynamics and metabolic levels. We provide here comprehensive codon optimization strategy based on gene level, transcriptional level, translational level, post-translational level and metabolic level, mainly including codon bias, codon harmonization, codon sensitivity, adjustment of gene sequence structure and some other influencing factors. We also summarize the aspects of strategy content, theoretical support and application. Besides, the advantages and disadvantages of each strategy are also systematically compared, providing an all-round, multi-level and multi-selection optimization strategy for heterogeneous protein expression, and also providing references for the enzyme industry and biopharmaceuticals.

Over-expression of Mycobacterium neoaurum 3-ketosteroid-∆ 1-dehydrogenase in Corynebacterium crenatum for efficient bioconversion of 4-androstene-3, 17-dione to androst-1, 4-diene-3, 17-dione

Background: 3-Ketosteroid-∆¹-dehydrogenase (KSDD), a flavoprotein enzyme, catalyzes the bioconversion of 4-androstene-3,17-dione (AD) to androst-1,4-diene-3,17-dione (ADD). To date, there has been no report about characterization of KSDD from Mycobacterium neoaurum strains, which were usually employed to produce AD or ADD by fermentation. Results: In this work, Corynebacterium crenatum was chosen asa new host for heterologous expression of KSDD from M. neoaurum JC-12 after codon optimization of the KSDD gene. SDS-PAGE and western blotting results indicated that the recombinant C. crenatum harboring the optimized ksdd (ksdd n) gene showed significantly improved ability to express KSDD. The expression level of KSDD was about 1.6-fold increased C. crenatum after codon optimization. After purification of the protein, we first characterized KSDD from M. neoaurum JC-12, and the results showed that the optimum temperature and pH for KSDD activity were 30°C and pH 7.0, respectively. The Km and Vmax values of purified KSDD were 8.91 µM and 6.43 mM/min. In this work, C. crenatum as a novel whole-cell catalyst was also employed and validated for bioconversion of AD to ADD. The highest transformation rate of AD to ADD by recombinant C. crenatum was about 83.87% after 10 h reaction time, which was more efficient than M. neoaurum JC-12 (only 3.56% at 10 h). Conclusions: In this work, basing on the codon optimization, overexpression, purification and characterization of KSDD, we constructed a novel system, the recombinant C. crenatum SYPA 5-5 expressing KSDD, to accumulate ADDfromADefficiently. This work provided new insights into strengthening sterol catabolism by overexpressing the key enzyme KSDD, for efficient ADD production.

Soluble expression of tandem hybrid ubiquitin-binding domains (ThUBD) in prokaryotic cytoplasm of Escherichia coli BL21(DE3) / 军事医学

Objective We increase the soluble expression of artificial tandem hybrid ubiquitin binding domains ( ThUBD) in prokaryotic cytoplasm of Escherichia coli BL21 ( DE3 ) , which offer an effective and special profiling for ubiquitin conjugates( UbC) .Methods Codon optimization of the ThUBD was performed, followed by analysis of codon relative adaptiveness based on relative frequency of synonymous codon ( RFSC) of E.coli.Further induced expression and yeast ubiquitin conjugate enrichment quantified the soluble ThUBD-S and tested the ability to bind UbC.Results The statistical result showed that the percentage of codon of the highest usage frequency was increased from 48%to 75%, and codon adaptation index( CAI) was increased from 0.63 to 0.88 after codon optimization, which might suggest a higher expression of the ThUBD in E.coli BL21 (DE3).The subsequent SDS-PAGE indicated that the soluble target protein was increased four times, which accounted for 13.06%of total cell lysis.Further ubiquitinated proteome of yeast demonstrated that the ability to bind and enrich UbC of optimized ThUBD-S did not change compared with original ThUBD.Conclusion The expression of ThUBD-S can quadruple after codon optimization.At the same time, codon optimization does not impact its soluble expression and the ability to bind UbC.

Purification and biological activity of recombinant human β-NGF expressed in E. coli / 中国药学杂志

OBJECTIVE: To express the recombinant human nerve growth factor by using codon mutation of Escherichia coli(rhβ-NGF), separate and purify the expression products, and determine the biological activity.

Codon optimization of the rabbit hemorrhagic disease virus (RHDV) capsid gene leads to increased gene expression in Spodoptera frugiperda 9 (Sf9) cells

Rabbit hemorrhagic disease (RHD) is contagious and highly lethal. Commercial vaccines against RHD are produced from the livers of experimentally infected rabbits. Although several groups have reported that recombinant subunit vaccines against rabbit hemorrhagic disease virus (RHDV) are promising, application of the vaccines has been restricted due to high production costs or low yield. In the present study, we performed codon optimization of the capsid gene to increase the number of preference codons and eliminate rare codons in Spodoptera frugiperda 9 (Sf9) cells. The capsid gene was then subcloned into the pFastBac plasmid, and the recombinant baculoviruses were identified with a plaque assay. As expected, expression of the optimized capsid protein was markedly increased in the Sf9 cells, and the recombinant capsid proteins self-assembled into virus-like particles (VLPs) that were released into the cell supernatant. Rabbits inoculated with the supernatant and the purified VLPs were protected against RHDV challenge. A rapid, specific antibody response against RHDV was detected by an ELISA in all of the experimental groups. In conclusion, this strategy of producing a recombinant subunit vaccine antigen can be used to develop a low-cost, insect cell-derived recombinant subunit vaccine against RHDV.

Codon optimization of 1, 3-propanediol oxidoreductase expression in escherichia coli and enzymatic properties

The gene dhaT from Klebsiella pneumoniae encoding 1,3-propanediol oxidoreductase (PDOR) was de novo synthesized by splicing overlap extension polymerase chain reaction (SOE-PCR) primarily according to Escherichia coli’s codon usage, as well as mRNA secondary structure. After optimization, Codon Adaptation Index (CAI) value was improved from 0.75 to 0.83, meanwhile energy of mRNA secondary structure was increased from -400.1 to -86.8 kcal/mol. This synthetic DNA was under control by phage T7 promoter in the expression vector pET-15b and transformed into the E. coli BL21 (DE3) strain. Inducers such as isopropyl beta-D-thiogalactoside (IPTG) and lactose were compared by activity at different inducing time. The activity of PDOR after codon optimized was 385.4 +/- 3.6 U/mL, which was almost 5-fold higher than wild type (82.3 +/- 1.5 U/ml) under the flask culture at 25ºC for 10 hrs. Then his-tagged enzyme was separated by using Ni-IDA column. The favorite environment for enzyme activity was at 5°C and pH 10.0, PDOR showed a certainly stability in potassium carbonate buffer for 2 hrs at diverse temperatures, enzyme activity was significantly improved by Mn2+.

Enhancing Protective Immunity Effects of TPI DNA Vaccine against Schistosoma japonicum through Codon Optimization / 中国寄生虫学与寄生虫病杂志

Objective To study the protective effect of codon optimized TPI DNA vaccine against Schistosoma japonicum infection.Methods Sixty female BALB/c mice were randomly divided into 5 groups.The mice were injected through musculus quadriceps fexoris with 100 ?g pcDNA 3.1 control(Group A), pcDNA3.1-TPI(Group B), pcDNA 3.1-TPI-mHSP70(Group C), pcDNA3.1-TPI.opt(Group D), and pcDNA3.1-TPI.opt-mHSP70(Group E) respectively.All mice were immunized for three times with an interval of two weeks.The mice were challenged with(40?1) cercariae of S.japonicum per mouse by abdominal skin penetration 4 weeks after the last immunization, and sacrificed at 42 days post-challenge, the number of worms or hepatic eggs was counted.Blood was taken for the detection of IgG, IgG1, and IgG2a 2 days before immunization and before challenge, respectively.Spleen cells of 2 mice from each group were cultured and stimulated with ConA and rSjCTPI peptide, and the supernatant was collected for detection of IL-2, IL-4, IL-5, IFN-?, and TNF by flow cytometry.Results ELISA showed that the mice in groups B, C, D, and E produced specific IgG and IgG1, IgG2a antibody isotypes, and the ratio of IgG2a/IgG1 was 1.73, 2.06, 2.44, and 3.09, respectively.The levels of IL-2, IFN-? and TNF in groups D and E were higher than that of groups B and C.The worm reduction rate and hepatic egg reduction rate in groups D(36.03%, 41.7%) and E(39.03%, 46.85%) were higher than those of groups B(26.28%, 28.35%) and C(28.38%, 31.39%)(P