Viral infection induces numerous tripartite motif (TRIM) proteins to control antiviral immune signaling and viral replication. Particularly, SPRY-containing TRIM proteins are found only in vertebrates and they control target protein degradation by their RING-finger and SPRY domains, and proper cytoplasmic localization. To understand TRIM30 function, we analyzed its localization pattern and putative roles of its RING-finger and SPRY domains. We found that TRIM30 is located in actin-mediated cytoplasmic bodies and produces colocalized ubiquitin chains in SPRY domain- and RING-finger domain-dependent ways that are degraded by autophagy and the proteasome. These results suggest a TRIM protein-dependent degradation mechanism by cytoplasmic body formation with actin networks.
Amino Acid Sequence ; Animals ; Autophagy ; Cell Line ; Inclusion Bodies/*metabolism ; Intracellular Signaling Peptides and Proteins/chemistry/genetics/*metabolism ; Mice ; Molecular Sequence Data ; Polyubiquitin/*metabolism ; Proteasome Endopeptidase Complex/metabolism ; Protein Interaction Domains and Motifs ; Protein Transport ; Proteolysis ; RING Finger Domains

This study is to optimize the preparation process of fusion protein Fv-LDP which was expressed in the form of inclusion body and consisted of lidamycin apoprotein LDP and single-chain Fv antibody (scFv) directed against type IV collagenase. The preparation and the dissolution of inclusion body, the immobilized metal affinity chromatography of the target protein and the renaturization by stepwise dialysis were optimized by single-factor analysis or orthogonal design. In addition, the refolded fusion protein Fv-LDP was refined by Sephadex G-75 chromatography followed by fluorescence-activated cell sorter (FACS)-based saturation binding assay to measure its antigen-binding activity. After optimization of the process, the purity of fusion protein Fv-LDP existed in the inclusion body was 63.9% and the corresponding solubility was 95.7%; Under denaturing conditions, the purity of fusion protein Fv-LDP was more than 95% after the purification process. The percentage of monomeric fusion protein Fv-LDP was 60% after the refolding process, while it was further refined to 85% which was 5.6-fold higher than that of the initial refolding condition. The refined fusion protein Fv-LDP could bind to human lung adenocarcinoma PAa cells and human hepatoma BEL-7402 cells with the dissociation constants (Kd) of 0.176 micromol x L(-1) and 0.904 micromol x L(-1), respectively. The preparation process of fusion protein Fv-LDP has been successfully optimized, which provides the experimental basis for the production and future development of fusion protein Fv-LDP, and might serve as a relatively practical system for the preparation of other scFv-based proteins expressed in the form of inclusion body.
Adenocarcinoma ; metabolism ; pathology ; Aminoglycosides ; chemistry ; metabolism ; Antibiotics, Antineoplastic ; chemistry ; metabolism ; Apoproteins ; chemistry ; metabolism ; Carcinoma, Hepatocellular ; metabolism ; pathology ; Cell Line, Tumor ; Collagenases ; immunology ; Enediynes ; chemistry ; metabolism ; Escherichia coli ; chemistry ; metabolism ; Humans ; Inclusion Bodies ; chemistry ; metabolism ; Liver Neoplasms ; metabolism ; pathology ; Lung Neoplasms ; metabolism ; pathology ; Protein Binding ; Recombinant Fusion Proteins ; chemistry ; metabolism ; Single-Chain Antibodies ; chemistry ; metabolism

The excretion characteristics of stilbene glycoside (THSG) and its beta-cyclodextrin inclusion in bile, urine and feces after oral administration to rats were studied. Bile for 24 h, urine and feces for 72 h were collected. The content of THSG was determined by HPLC-UV. The established HPLC-UV method was available for the analysis of THSG in excreta and corresponded to the requirement of biological sample analysis. After given THSG and its beta-cyclodextrin inclusion, the amount of prototype THSG in feces were 3.27% and 0.61%, meanwhile THSG in bile were 0.20% and 0.18%, respectively. Only a little THSG was found in urine. The result showed that beta-cyclodextrin inclusion reduced the fecal excretion of THSG. However, the characteristic of urinary and biliary excretion wasn't changed.
Administration, Oral ; Animals ; Bile ; metabolism ; secretion ; Biological Transport ; physiology ; Chromatography, High Pressure Liquid ; methods ; Feces ; Glycosides ; chemistry ; Inclusion Bodies ; secretion ; Injections, Intravenous ; Male ; Rats ; Rats, Sprague-Dawley ; Stilbenes ; administration & dosage ; chemistry ; beta-Cyclodextrins ; metabolism

OBJECTIVETo express the carbohydrate recognition domain (CRD) of Balb/C mouse mannan binding lectin A (MBL-A) in E.coli.

METHODSThe target gene fragment was obtained by PCR from the plasmid pmMBL-A harboring mouse MBL-A gene. The PCR product was recombined with the prokaryotic expression vector pET-41a(+) and the resulting recombinant plasmid was identified by PCR, restriction analysis and sequencing before transformation into E.coli BL21(DE3) cell for expression of the target protein. After washing and renaturation, the protein was purified on GST-Tag purification resins and analyzed by SDS-PAGE, Western blotting and enzyme-linked immunosorbent assay (ELISA).

RESULTSA DNA fragment of about 450 bp was amplified by PCR and the recombinant plasmid pET41a-mMBL-A-CRD was constructed by linking the fragment with pET41a(+) vector. The result of restriction enzyme analysis and sequencing of the selected clones were consistent with those by computer analysis. The recombinant vector was expressed in E.coli BL21(DE3), and the expressed protein existed mainly as inclusion bodies, whose relative molecular mass was about 47,000 by SDS-PAGE analysis. After washing, renaturation and purification, the purity of recombinant protein was about 90%. Western blotting suggested immunoreactivity of the purified protein with anti-GST antibody, and its sugar binding activity was verified by ELISA.

CONCLUSIONWe have successfully obtained mouse MBL-A CRD protein, which provides the base for further functional study of the MBL-A molecule.

Animals ; Carbohydrates ; chemistry ; Escherichia coli ; genetics ; metabolism ; Genetic Vectors ; Inclusion Bodies ; metabolism ; Mannose-Binding Lectin ; biosynthesis ; chemistry ; genetics ; Mice ; Mice, Inbred BALB C ; Recombinant Fusion Proteins ; biosynthesis ; chemistry ; genetics

OBJECTIVETo establish a prediction method for the refolding of inclusion bodies and classify refolding types of different inclusion bodies directly from their primary structure to improve the efficiency of high throughput refolding process.

METHODSForty-three recombinant proteins performing important biological functions were expressed in E. coli. The probability of forming inclusion bodies of these proteins was predicted using Harrison's two parameter prediction model based on the proteins' amino acid composition. Subsequently, the proteins from the inclusion bodies were refolded using a double denaturation method that involved washing and denaturation in GdnHCl solution followed by denaturation in Urea solution and refolding through dilution.

RESULTSAll the proteins were detected in the form of inclusion bodies using SDS-PAGE method. The proteins were divided into two types according to the results of both solubility prediction and refolding experiments. Fourteen proteins were predicted to have the dependency of soluble expression. The refolding yields of these inclusion bodies were up to 70%. Twenty-nine proteins were predicted to have the high dependency of insoluble expression, and their refolding yields could be higher than 70% and lower than 60%. Comparison of the characteristics between the proteins with high and low refolding yields showed that the theoretical pI was significantly different (P<0.05).

CONCLUSIONSHarrison's two parameter prediction model has the value for potential application in classification of the inclusion bodies and prediction of solubility of proteins refolded from different inclusion bodies. This a novel method enhances the efficiency of high throughput refolding of inclusion bodies, and suggests that the theoretical pI of the proteins is an important parameter in the prediction of refolding yields.

Escherichia coli ; genetics ; metabolism ; Escherichia coli Proteins ; chemistry ; genetics ; Genetic Vectors ; genetics ; Inclusion Bodies ; chemistry ; Models, Biological ; Protein Refolding ; Recombinant Proteins ; biosynthesis ; genetics

X5 protein is one of the putative unknown proteins of SARS-CoV. The recombinant protein has been successfully expressed in E. coli in the form of insoluble inclusion body. The inclusion body was dissolved in high concentration of urea. Affinity Chromatography was preformed to purify the denatured protein, and then the product was refolded in a series of gradient solutions of urea. The purified protein was obtained with the purity of > 95% and the yield of 93.3 mg x L(-1). Polyclonal antibody of this protein was obtained, and Western blotting assay indicated that the X5 protein has the strong property of antigen. Sixty-eight percent of the recombinant protein sequence was confirmed by LC-ESI-MS/MS analysis.
Amino Acid Sequence ; Animals ; Antibodies ; isolation & purification ; Escherichia coli ; genetics ; metabolism ; Gene Expression Regulation, Viral ; Inclusion Bodies ; chemistry ; metabolism ; Molecular Sequence Data ; Rabbits ; Recombinant Proteins ; genetics ; immunology ; isolation & purification ; SARS Virus ; genetics ; Viral Proteins ; genetics ; immunology ; isolation & purification

To investigate the effects of induction temperature on the expression product and the impact of urea concentration on the purification, HIV-1 Gag inclusion bodies from E. coli induced at 30 degrees C (IB30) and 37 degrees C (IB37) were dissolved with urea of different concentrations. The solubility and yield of refolding were compared. IB30 were dissolved with 2 mol/L and 8 mol/L urea, and then purified with chromatography. IB30 were found easier to be solubilized in low concentration of urea and easier to be refolded than IB37. Furthermore, compared to the IB30 dissolved in 8 mol/L urea, Gag protein solubilized in 2 mol/L urea was purified to higher purity with gel filtration (GF) and ion exchange (IEX) chromatography. Gag inclusion body induced at lower temperature may contain more protein with native-like or reversibly-denatured structures, and solubilization in the presence of low concentrations of urea can help to retain these structures. This study has provided new insights into the purification of proteins from inclusion bodies.
Escherichia coli ; genetics ; metabolism ; HIV-1 ; genetics ; Humans ; Inclusion Bodies ; metabolism ; Protein Denaturation ; Recombinant Proteins ; biosynthesis ; genetics ; isolation & purification ; Temperature ; Urea ; chemistry ; gag Gene Products, Human Immunodeficiency Virus ; biosynthesis ; genetics

The argE gene from Escherichia coli coding for N-acety-L-ornithine deacetylase(NAOase), the key enzyme involved in the L-arginine biosynthesis, had been cloned in pET22b and transformed into BL21 (DE3). With 32.5% expression level in the optimal fermentation medium at 37 degrees C, most NAOase was expressed as inclusion bodies. The soluble and active proportion could be slightly increased when expressed at low temperature. The specific activity of soluble NAOase purified by Ni-NTA resin chromatography was 1193.2u/mg. The species and proportions of whole cell proteins varied with induction conditions. The inclusion bodies expressed at 37 degrees C was more pure than 22 degrees C after gradient wash with urea. Inclusion bodies could be partly refolding and reactivated by dilution and dialysis. Low protein concentration and suitable rate of oxidant/reducing agents were important to renaturation. In the optimal conditions 17.78% of Urea-denatured NAOase could be refolding and reactivated by dilution. The purified fusion protein was obtained after wash, solubilization and Ni-NTA resin affinity chromatography purification of inclusion bodies.
Amidohydrolases ; chemistry ; genetics ; metabolism ; Biocatalysis ; drug effects ; Electrophoresis, Polyacrylamide Gel ; Escherichia coli ; enzymology ; genetics ; Escherichia coli Proteins ; genetics ; metabolism ; Gene Expression Regulation, Bacterial ; Gene Expression Regulation, Enzymologic ; Inclusion Bodies ; enzymology ; Protein Folding ; drug effects ; Recombinant Proteins ; chemistry ; isolation & purification ; metabolism ; Urea ; pharmacology

Overexpression of recombinant Human Cu, Zn-Superoxide Dismutase (rhCu, Zn-SOD) in E. coli results in the form of insoluble inclusion body. Purity of rhSOD inclusion body was over 80% by isolation and purification. After preliminary renaturation by conventional dilution or dialysis, enzyme preparations was respectively purified by using Copper Metals-Chelating Affinity Chromatography (Copper-MCAC). RhSOD specific activity purified by MCAC (from the sample renatured partly by dialysis) was 2.2 times as much as that by dialysis and protein recovery was 64%. RhSOD specific activity purified by MCAC (from the sample renatured partly by dilution) was 5.3 times as much as that by dilution and protein recovery was 25%. The two rhSOD preparations purified by MCAC had specific activities about 5000 u/mg and activity recoveries were all over 130% of the enzyme activities in the samples renatured partly by dilution or dialysis. The above-mentioned results indicated that Copper-MCAC resulted in a purification and further renaturation of target protein. SDS-PAGE showed that the target protein rhSOD (19 kD) was purified homogeneously and NBT activity identification proved that the purified and renatured rhSOD had very strong SOD activity. In conclusion, Copper Metals-Chelaing Affinity Chromatography appears to be a simple, rapid and efficient procedure for purifying and further renaturing rhCu, Zn-SOD by dilution or dialysis. The method provided a new idea for purifying and renaturing recombinant proteins expressed in the form of inclusion body in E. coli.
Chelating Agents ; chemistry ; Chromatography, Affinity ; methods ; Escherichia coli ; genetics ; metabolism ; Humans ; Inclusion Bodies ; genetics ; Protein Renaturation ; Recombinant Proteins ; biosynthesis ; genetics ; isolation & purification ; Superoxide Dismutase ; biosynthesis ; genetics

A novel human ScFv H12 against SARS-CoV has been selected from a SARS immune library. In order to produce a large amount of ScFv H12, pET28a-H12 expression vector was constructed and ScFv H12 was expressed at yield about 30% of total proteins in E. coli . Here two different refolding procedures were used to refold ScFv H12 from inclusion body: gel filtration chromatography and dilution. The results showed that ScFv H12 could be efficiently refolded by both procedures. However, the refolding via gel filtration was 1.5 time more effective than that of dilution. The affinity of ScFv H12 to SARS-CoV virion was detected as Kd = 73.5 nmol/mL.
Antibodies, Monoclonal ; biosynthesis ; genetics ; Antibodies, Viral ; immunology ; Escherichia coli ; genetics ; metabolism ; Humans ; Immunoglobulin Fragments ; biosynthesis ; genetics ; immunology ; Immunoglobulin Variable Region ; biosynthesis ; genetics ; immunology ; Inclusion Bodies ; genetics ; immunology ; Protein Renaturation ; Recombinant Proteins ; biosynthesis ; chemistry ; immunology ; SARS Virus ; immunology