[cloning of the hepatitis b virus genome in escherichia coli].the whole genome of the hepatitis b virus (dane particles) was inserted in vitro in the genome of the bacteriophage lambda gtwes . lambda b. the recombinant dna molecule was cloned in e. coli. amplification of the hybrid bacteriophage enables the preparation of large amounts of hepatitis b virus dna. the possibilities offered by the utilization of this recombinant bacteriophage are discussed.1978158442
cloning in escherichia coli and physical structure of hepatitis b virion dna.a restriction map of hepatitis b virion dna was established after cloning of the whole viral genome in escherichia coli. by use of ecori, xho i, bgl ii, xba i, bamhi, hincii, and hae iii endonucleases, a total of 28 restriction sites were mapped. the single-stranded region was localized on the restriction map and 5' end of the short strand was mapped at a fixed position.1979377294
hepatitis b virus envelope epitopes: gene assembly and expression in escherichia coli of an immunologically reactive novel multiple-epitope polypeptide 1 (mep-1).a novel synthetic 323-bp gene with the open reading frame of a multiple-epitope polypeptide has been assembled and cloned. the gene is engineered by contiguous alignment of selected epitopes and functional domains of the hepatitis b virus envelope proteins separated by pairs of glycine residues. high-level bacterial production of this 100-amino acid (approx. 10 kda) protein has been achieved and the gene product is stable. elisa and western blot experiments using epitope-specific antisera confir ...19921371488
production of a soluble and secreted antigenic fragment of hbsag in yeast.we have produced a fragment of hepatitis b surface antigen (hbsag) corresponding to amino acids 1-60 as a fusion protein with the alpha mating factor of yeast. the product is secreted from yeast as a soluble monomer that expresses hbsag antigenicity. unlike other heterologous fusion proteins, it is not processed by the lys-arg endoprotease, possibly due to a proline in the linker between the two coding sequences. the resulting soluble fragment will enable us to map the immunodominant sites of hb ...19921567451
search for hepatitis b virus cell receptors reveals binding sites for interleukin 6 on the virus envelope protein.the major target organ for hepatitis b virus (hbv) is the liver. however, cells other than hepatocytes, including peripheral blood lymphocytes and monocytes, may become infected with hbv. the cell receptor binding site was assigned to the pres(21-47) segment of the hbv envelope protein. hbv receptors were detected on human liver and hepatoma cells, on b lymphocytes, and, as shown here, on monocytes, and t cell lines, activated by escherichia coli lipopolysaccharide and concanavalin a, respective ...19921732412
expression of multivalent pre-s1 antigen of hepatitis b virus in escherichia coli (synthetic oligodeoxynucleotides, surface antigens, recombinant dna, fusion protein, beta-galactosidase).the nucleotide sequence encoding 30 amino acids (aa) of the pre-s1 envelope region of the human hepatitis b virus has been constructed from twenty chemically synthesized oligodeoxynucleotides by simultaneous ligation. the dna fragment containing four repeated sequences encoding the pre-s1 region (aa 20-49) has been inserted into the lacz gene of the plasmid pwr450.1, yielding the recombinant pwx4 plasmid. the escherichia coli dh5 strain transformed with pwx4 produces a beta-galactosidase-[-pre-s ...19911821612
peripheral blood cd4-mediated enhancement and cd8-mediated suppression in the presence of recombinant hepatitis b virus core antigen.the proliferative response of peripheral blood t cells to hepatitis b core antigen (hbcag) was studied in hepatitis b patients. cd4+ t cells from patients with chronic active hepatitis type b (cah-b) exhibited a significant proliferative response to hbcag, especially in hepatitis b envelope antigen (hbeag)-positive patients. in contrast, there was no apparent t cell reaction to hbcag in patients with cah non-a, non-b, hbeag-positive healthy carriers and in healthy volunteers. the proliferative r ...19901968934
cloning, sequencing and expression in escherichia coli of cdna for a non-a, non-b hepatitis-associated microtubular aggregates protein.a 1.7 kb cdna encoding a novel antigen (p44; apparent mr 44k) associated with non-a, non-b (nanb) hepatitis, was isolated from the hepatic cdna library of a chimpanzee infected with nanb hepatitis. the library was screened with a monoclonal antibody against this antigen. the cdna cloned contained an open reading frame encoding a 444 amino acid protein with an mr calculated to be 50,468. the cdna hybridized to a 1.9 kb mrna obtained from chimpanzee hepatocytes infected with either the nanb or hep ...19902170570
transcriptional activation of the human immunodeficiency virus type 1 long terminal repeat by hepatitis b virus x-protein requires de novo protein synthesis.human hepatitis b virus (hbv) x-gene, previously shown to be capable of trans-activating heterologous regulatory elements of the human beta-interferon gene, the human immunodeficiency virus type i (hiv-1) long terminal repeat (ltr), the simian virus 40 (sv40), and hbv, has the capacity to code for a 17-kda polypeptide (designated px17). we now report that px17 synthesized in escherichia coli can activate transcription controlled by the hiv-1 ltr using a protoplast fusion technique. protoplasts o ...19902191500
the hepatitis b virus-encoded transcriptional trans-activator hbx appears to be a novel protein serine/threonine study the functional mechanism of the hepatitis b virus (hbv) x (hbx) gene product, we have expressed the hbx protein in e. coli and purified it by hplc. the purified hbx protein was shown to be active in transactivating transcription directed by the ltr sequence of hiv-1. the hbx protein was found to have an intrinsic serine/threonine protein kinase activity. the hbx protein was detected in hepatitis b virions, and tryptic phosphopeptide maps of the hbx protein phosphorylated in the virion a ...19902225072
enhancement of humoral immune responses against viral vaccines by a non-pyrogenic 6-o-acylmuramyldipeptide and synthetic low toxicity analogues of lipid a.6-o-acyl derivatives of n-acetylmuramyl-l-alanyl-d-isoglutamine (mdp) and synthetic, low toxicity lipid-a analogues were examined for their ability to enhance the potency of current viral vaccines. 6-o-(2-tetradecylhexadecanoyl)-mdp (b30-mdp) in non-irritative vehicles such as physiological saline, phosphate-buffered saline (pbs), squalene-pbs emulsion, intralipid or liposomes, significantly stimulated the primary and secondary antibody production of guinea-pigs against influenza split or subuni ...19892718605
characterization of large surface proteins of hepatitis b virus by antibodies to pres-s encoded amino acids.the major surface protein of hbv, the 226-amino-acid hbsag, is encoded in the 3' proximal segment of the pres-s gene of 389 codons. to identify gene products from the 5' proximal pres sequence, dna fragments from the pres region were expressed in escherichia coli as fusion proteins. antisera prepared against these fusions were used to screen serum proteins of hbv-infected individuals, and found to react specifically with the two large hbv surface proteins of 39 and 42 kda. the presence of these ...19863510505
detection of hepatitis b virus x product using an open reading frame escherichia coli expression vector.the genome of the hepatitis b virus (hbv) contains a sequence, designated x, capable of encoding a protein of 154 amino acids. to determine whether the putative protein synthesized from this region is antigenic, we examined the sera of hbv-infected patients for the ability to react with a hybrid protein that contained 133 amino acids encoded by the x region and portions of the bacterial ompf and beta-galactosidase genes. some hbv-positive sera tested contained antibodies that specifically recogn ...19863515347
[gene expression of the surface antigen of the hepatitis b virus in yeast cells]. 19863537767
t lymphocyte sensitization to hbcag and t cell-mediated unresponsiveness to hbsag in hepatitis b virus-related chronic liver disease.using a newly developed indirect t lymphocyte migration inhibition test, cell-mediated immunity to hbsag and hbcag was directly and simultaneously examined in a total of 21 patients with hbsag-positive chronic liver disease (cld), and in seven subjects whose sera contained anti-hbs (2 previous acute hepatitis b; 4 hepatitis b vaccine recipients and 1 chronic active hepatitis). t cell sensitization to hbcag was invariably detected in the hbsag-positive cld patients tested (12/12), whereas t cell ...19853884475
dna cloned from the ayw subtype of hepatitis b virus.dna from the ayw subtype of hepatitis b virus (hbv) was ligated into the ecori site of dna from plasmid pbr322 and propagated in e coli chi 776. a plasmid with a 3200 base pair insert (phbv-1) was isolated and the cloned hbv dna was mapped with restriction endonucleases. differences were found in restriction endonuclease cleavage sites for dnas from hbv of subtype ayw and adr.19806264021
plasmid-directed synthesis of hepatitis b surface antigen in monkey cells.we introduced the gene encoding the hepatitis b virus surface antigen (hbsag) into simian virus 40 (sv40)-based plasmids capable of autonomously replicating in both escherichia coli and permissive monkey cells. after introduction into monkey cells by transfection, these plasmids directed the synthesis of high levels of hbsag, as determined by immunofluorescence, radioimmunoassays, and identification by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the polypeptides comprising the a ...19836298607
[synthesis of the surface antigen of the hepatitis b virus in escherichia coli]. 19836352218
hepatitis b virus surface antigen production in escherichia coli. 19817015415
hepatitis b virus core antigen: synthesis in escherichia coli and application in diagnosis.fragments of hepatitis b virus dna cloned in plasmid pbr322 carrying the gene for the viral core antigen have been placed under the control of the lac promoter of escherichia coli. several of the new recombinants direct higher levels of synthesis of the antigen, but the degree of enhancement varies with the different structures of the plasmids and hence the mrnas produced. the antigen in crude bacterial lysates is a satisfactory diagnostic reagent for antibodies to the core antigen in serum samp ...19827041126
evaluation of in vitro efficacy of the disinfectant virkon.a study was conducted on a new acid peroxygen system based disinfectant (virkon), in order to assess its in vitro efficacy. the chemical was tested on different bacteria (staphylococcus aureus, pseudomonas aeruginosa, escherichia coli), spores (bacillus subtilis) and on the hepatitis b surface antigen (hbsag), and compared in its activity with phenol and glutaraldehyde (calculation of the 'phenol coefficient' and the 'glutaraldehyde coefficient'). the constancy of speed of disinfection, the coef ...19957672075
efficient in vivo transduction of the neonatal mouse liver with pseudotyped retroviral vectors.ideal methods for human gene therapy will eventually include direct gene transfer to defective tissues in a patient in vivo. toward that goal, we have used high titer, pseudotyped retroviral vectors expressing genes for the escherichia coli beta-galactosidase (lacz) or hepatitis b virus surface antigen (hbsag) to infect mouse liver by in vivo direct injection into the liver parenchyma. we have found that a single percutaneous injection of small volumes of vectors into the newborn mouse liver lea ...19957719930
demonstration of the presence of protease-cutting site in the spacer of hepatitis b viral pol protein.molecular genetic studies have revealed that the human hepatitis b viral (hbv) pol protein, a polypeptide of about 94 kda, contains four domains. these are the 5'-terminal protein, spacer, rna reverse transcriptase/dna polymerase, and rnase h, respectively, from the amino (n) to carboxy (c) terminus. no evidence indicates as yet the involvement of a specific protease in cleaving the pol protein or the presence of protease-cutting sites in the pol protein. an in vitro-translated pol protein was s ...19957730438
study on reliability of commercially available hepatitis c virus antibody tests.the serodiagnosis of hepatitis c virus (hcv) infection was analyzed by a recombinant immunoblot assay (riba) with recombinant proteins encoded by the viral rna isolated from our patients in hamburg, germany. the hcv rna was amplified by pcr, and proteins encoded by the viral core and the ns3, ns4, and ns5 regions were expressed subsequently in escherichia coli. the results obtained with our uke riba were compared with the results of the abbott hcv second-generation enzyme immunoassay (eia). seru ...19957751366
selected mutations of the duck hepatitis b virus p gene rnase h domain affect both rna packaging and priming of minus-strand dna synthesis.the genome of all hepadnaviruses has an open reading frame called the p gene, which encodes a polypeptide of 90 to 97 kda. the product or products of this p gene are involved in multiple functions of the viral life cycle. these functions include a priming activity which initiates minus-strand dna synthesis, a polymerase activity which synthesizes dna by using either rna or dna templates (reverse transcriptase), a nuclease activity which degrades the rna strand of rna-dna hybrids (rnase h), and i ...19948035519
chimeric hepatitis b virus core particles with parts or copies of the hepatitis c virus core protein.either parts or multiple copies of the core gene of hepatitis c virus (hcv) were fused to the 3' terminus of the hepatitis b virus (hbv) core gene with 34 codons removed. as many as four copies of hcv core protein (720 amino acids) were fused to the carboxy terminus of truncated hbv core protein (149 amino acids) without preventing the assembly of hbv core particles. chimeric core particles were sandwiched between monoclonal antibody to hbv core and that to hcv core, thereby indicating that anti ...19938396669
a truncated mutant (residues 58-140) of the hepatitis b virus x protein retains transactivation function.the hepatitis b virus x protein (hbx) sequence (154 aa) has been divided into six regions (a-f) based on its sequence homology with x proteins of other mammalian hepadnaviruses. regions a, c, and e are more conserved and include all the four conserved cysteines (c7, c61, c69, and c137). to localize the regions of hbx important for transactivation, a panel of 10 deletion mutants (x5-x14) and 4 single point mutants (x1-x4), each corresponding to a conserved cysteine residue, was constructed by sit ...19968643631
hybrid hepatitis b virus core antigen as a vaccine carrier moiety: i. presentation of foreign epitopes.hepatitis b virus (hbv) core antigen (hbcag) is a highly immunogenic subviral particle. here, we review recent progress in the use of hbcag as a carrier moiety for heterologous epitopes. to define surface exposed and immunogenic insertion sites for foreign epitopes in hbcag, peptidic epitopes representing binding sites for virus neutralizing antibodies on the hbv surface antigens were inserted at different positions within hbcag using genetic engineering in an escherichia coli expression system ...19968717391
hepatitis b virus core-pres2 particles expressed by recombinant vaccinia virus.vaccinia virus (vv) recombinants expressing hepatitis b virus (hbv) surface (hbsag) or core (hbcag) antigens (kunke et al., virology 195, 132 - 139 (1993)] have been shown to raise specific antibodies in mice, nevertheless the levels of antibodies reactive with the pres2 and s antigens were low. in an attempt to enhance the immunogenicity of hbsag-pres2, a fused c-pres2 gene was constructed. the fusion protein was expressed in e. coli and displayed both hbcag and pres2 antigen as demonstrated by ...19969171455
[development of an enzyme assay for detection of hepatitis b virus core igm antibodies].detection of igm anti-core (anti-hbcag) antibodies of hepatitis b virus (hbv) is an useful marker for hepatitis b virus (hbv) acute infection. the aim of this study was to perform an immunodiagnostic assay for the detection of igm anti-hbcag antibodies. hepatitis b core antigen (hbcag) was produced by a recombinant clone of escherichia coli and used for the development of the immunoassay. an igm capture enzyme immunoassay (eia) was selected for the detection of igm anti-hbcag antibodies. a total ...19989586397
bacterial expression of a human recombinant monoclonal antibody fab fragment against hepatitis b surface antigen.the fab fragment was cloned from the monoclonal cell line tapc301-cl4, which was produced using the epstein-barr virus (ebv) transformation method. this cell line produces a human monoclonal antibody (cl4mab) against the hepatitis b surface antigen (hbsag). this mab was shown to have hepatitis b virus (hbv) neutralizing activity in chimpanzees. the fab fragment was produced by subjecting the heavy and light chain antibody genes of the tapc301-cl4 cell line to reverse transcription-polymerase cha ...199910421399
new chimaeric hepatitis b virus core particles carrying hantavirus (serotype puumala) epitopes: immunogenicity and protection against virus challenge.virus-like particles generated by the heterologous expression of virus structural proteins are able to potentiate the immunogenicity of foreign epitopes presented on their surface. in recent years epitopes of various origin have been inserted into the core antigen of hepatitis b virus (hbv) allowing the formation of chimaeric hbv core particles. chimaeric core particles carrying the 45 n-terminal amino acids of the puumala hantavirus nucleocapsid protein induced protective immunity in bank voles ...199910486924
characterization and diagnostic potential of hepatitis b virus nucleocapsid expressed in e. coli and p. pastoris.the hepatitis b core antigen (hbcag) was expressed in escherichia coli and in pichia pastoris. a hexahistidine tag was introduced at the c terminus of the e. coli expressed protein allowing its purification by ni(2+)-chelate affinity chromatography. the p. pastoris expressed hbcag was isolated following heat treatment. the two recombinant hbcags were purified further on a sucrose gradient. mass spectrometry analysis suggested that hbcag was n-acetylated only in p. pastoris and reaction with ellm ...200211684308
analysis of laci mutations in big blue transgenic mice subjected to parasite-induced inflammation.parasite infections have long been associated with specific types of human cancers. schistosoma hematobium is an inducer of urinary bladder cancer, helicobacter pylori is a gastric carcinogen, and hepatitis b virus and opisthorchis viverrini are causative agents of hepatocellular carcinoma. another liver fluke, fasciola hepatica, has also been identified as a neoplastic risk agent, primarily in animals. we used f. hepatica-induced inflammation in mice to determine if the presence of an aggressiv ...200111733073
woodchuck gamma interferon upregulates major histocompatibility complex class i transcription but is unable to deplete woodchuck hepatitis virus replication intermediates and rnas in persistently infected woodchuck primary hepatocytes.gamma interferon (ifn-gamma) is an important mediator with multiple functions in the host defense against viral infection. ifn-gamma, in concert with tumor necrosis factor alpha (tnf-alpha), leads to a remarkable reduction of intrahepatic replication intermediates and specific mrnas of hepatitis b virus (hbv) by a noncytolytic mechanism in the transgenic mouse model. thus, it is rational to evaluate the potential value of ifn-gamma for the treatment of chronic hbv infection. in the present study ...200211739671
bacterial expression, purification, and in vitro n-myristoylation of fusion hepatitis b virus pres1 with the native-type n-terminus.very low-level expression of hepatitis b virus (hbv) pres1 with the native-type n-terminus hampered the biochemical and functional studies on its myristoylation. in the present study, the fusion hbv pres1 with the native-type n-terminus and a his6-tag fused to c-terminus (hbv pres1-ht) was highly expressed in escherichia coli. this was due to an introduced mutation of the rare codon gga found in the hbv pres1 to the codon preferred by e. coli, ggu. the protein was rapidly purified from bacterial ...200312509984
efficient hsp90-independent in vitro activation by hsc70 and hsp40 of duck hepatitis b virus reverse transcriptase, an assumed hsp90 client protein.hsp90 is a specialized chaperone that controls the activity of many key regulator proteins such as steroid hormone receptors (shrs). hormone binding, and therefore shr activation, requires hsp90, which is loaded onto the receptors by a series of events involving hsp70, hsp40, hop, and p23. the reverse transcriptase (rt) of hepatitis b viruses, small dna-containing viruses that replicate via an rna intermediate, has been reported to depend similarly on hsp90 for enzymatic activity. using an in vi ...200312851401
detection of the hepatitis b virus x protein (hbx) antigen and anti-hbx antibodies in cases of human hepatocellular carcinoma.hepatitis b virus x protein (hbx) expressed in escherichia coli dh5alpha by recombinant dna technology was purified to homogeneity by use of glutathione-sepharose beads. immunological characterization of the recombinant hbx protein was performed. specific binding between the anti-hbx monoclonal antibody and hbx protein showed the specificity of the recombinant hbx protein. the intact hbx protein of the factor xa-digested glutathione s-transferase-hbx fusion protein was further purified and was u ...200314662947
in vitro reconstitution of epsilon-dependent duck hepatitis b virus replication initiation. 200414762314
[mutual interaction between hepatitis b virus antigen and metallothionein].to screen and identify the protein interacting with hbv antigen in hepatocytes. then investigate the biological functions of hepatitis b virus antigen in the pathogenesis of hepatitis b and seek effective methods to prevent and treat it.200415387906
antigenic complementarity resulting in idiotype-antiidiotype immune complexes: possible contributor to aids pathogenesis and hundred and sixty seven combinations of viral + viral antibodies or viral + bacterial antibodies were tested for their ability to precipitate each other. some antibodies produced against hiv epitopes recognize and precipitate some antibodies produced against cytomegalovirus (cmv), hepatitis b virus (hbv) core antigen, and mycobacteria tuberculosis (mtb) and staphylococcus epitopes but not those against hbv surface antigen, herpes simplex types 1 and 2 (hsv1 and hsv2) or epstein-barr virus (e ...200415497453
molecular characterization of woodchuck interleukin 15 (wil-15) and detection of its expression in liver samples of woodchucks infected with woodchuck hepatitis virus (whv).interleukin 15 (il-15) is a member of the four-helix bundle cytokine family and has t cell growth factor activity. il-15 plays a unique role in both innate and adaptive immune cell homeostasis, particularly for the development of nk cells and cd8+memory cells. it may be useful for stimulation of specific immune responses in chronic viral infection such as hepatitis b virus infection. the woodchuck model is an informative animal model for studies on hepadnavirus infection and therapeutic interven ...200616406557
antimicrobial and antiviral screening of novel indole carboxamide and propanamide derivatives.a few series of indole derivatives were screened for antimicrobial, antifungal and anti-hbv activities. the compounds were tested for their in vitro antibacterial activity against staphylococcus aureus, bacillus subtilis, escherichia coli and for their antifungal activity against candida albicans using a disc diffusion method, which measures the diameter of the inhibition zone around a paper disc soaked in a solution of the test compounds. the antimicrobial activity results showed that all compo ...200818533460
n-terminally his-tagged hepatitis b core antigens: construction, expression, purification and antigenicity.the core antigen of the hepatitis b virus (hbcag) has been used widely as a diagnostic reagent for the identification of the viral infection. however, purification using the conventional sucrose density gradient ultracentrifugation is time consuming and costly. to overcome this, hbcag particles displaying his-tag on their surface were constructed and produced in escherichia coli. the recombinant his-tagged hbcags were purified using immobilized metal affinity chromatography. transmission electro ...200919433111
enhancement of mucosal immune response against the m2ehbc+ antigen in mice with the fusion expression products of ltb and m2ehbc+ through mucosal immunization route.m2e is the external domain of m2 protein, a conservative transmembrane protein of the avian influenza a virus. previous research had shown that the vaccine of the formation particle of m2e and hepatitis b virus core antigen (hbcag) can fully protect mice against a lethal h5n1 subtype avian influenza virus (aiv) infection. as an effective approach against mucosal tissue infectious agent, mucosal vaccination requires effective and safe adjuvants. here we have first fused two m2e peptide to the n t ...200919462253
melanoma vaccine candidates from chimeric hepatitis b core virus-like particles carrying a tumor-associated mage-3 epitope.vaccination of melanoma patients with tumor-specific antigens recognized by cytotoxic t lymphocytes (ctls) may produce significant tumor regressions. here, we suggest a novel type of tumor vaccines, with well-studied ctl epitopes presented on highly immunogenic virus-like particle (vlp) carriers. cancer-germline gene mage-3 encodes for an antigenic nonapeptide (mage-3(168-176) peptide) that is recognized by ctls on human leukocyte antigen (hla)-a1 and hla-b35 molecules. a set of recombinant gene ...200818956370
optimization of the expression of hepatitis b virus e gene in pichia pastoris and immunological characterization of the product.escherichia coli-derived hepatitis b e antigen (hbeag) is widely used for serological tests of hepatitis b virus (hbv). because it exhibits cross-reactivity with hbcab in human sera, current antibody to hbeag (hbeab) immunoassays are based on competitive inhibition enzyme-linked immunosorbent assay (elisa) rather than sandwich elisa, which interfere with the specificity and sensitivity of hbeab detection. pichia pastoris has advantages of eukaryotic cells, while having the capacity of high-level ...200818721834
phosphorylation of hepatitis b virus core c-terminally truncated protein (cp149) by pkc increases capsid assembly and stability.the hbv (hepatitis b virus) core is a phosphoprotein whose assembly, replication, encapsidation and localization are regulated by phosphorylation. it is known that pkc (protein kinase c) regulates pgrna (pregenomic rna) encapsidation by phosphorylation of the c-terminus of core, which is a component packaged into capsid. neither the n-terminal residue phosphorylated by pkc nor the role of the c-terminal phosphorylation have been cleary defined. in the present study we found that hbv cp149 (core ...200818605987
recombinant hepatitis b virus core particles: association, dissociation and encapsidation of green fluorescent protein.the recombinant hepatitis b virus (hbv) core antigen (hbcag) expressed in escherichia coli self-assembles into icosahedral capsids of about 35 nm which can be exploited as gene or drug delivery vehicles. the association and dissociation properties of the c-terminally truncated hbcag with urea and guanidine hydrochloride (gdnhcl) were studied. transmission electron microscopy (tem) revealed that the dissociated hbcag was able to re-associate into particles when the applied denaturing agents were ...200818584885
ribosome can resume the translation in both +1 or -1 frames after encountering an aga cluster in escherichia escherichia coli the rare codons agg, aga and cga are reported to have a detrimental effect on protein synthesis, especially during the expression of heterologous proteins. in the present work, we have studied the impact of successive clusters of these rare codons on the accuracy of mrna translation in e. coli. for this purpose, we have analyzed the expression of an mrna which contains in its 3' region a triplet and a tandem of aga codons. this mrna is derived from the human hepatitis b virus ...200818313865
expression, purification and characterization of full-length rna-free hepatitis b core particles.the nucleocapsid or core particle of the hepatitis b virus has become one of the favourite recombinant vaccine carriers for foreign peptides, proteins and stimulatory oligonucleotides. the core protein consists of three regions: an n-terminal, a central and a c-terminal region that can accommodate the addition or insertion of the foreign sequences. the protamine-like c-terminal region that binds host rna randomly during recombinant particle formation is often truncated. it is commonly thought th ...200717387023
protein transduction with bacterial cytosine deaminase fused to the tlm intercellular transport motif induces profound chemosensitivity to 5-fluorocytosine in human hepatoma cells.this study investigates the application of protein based therapeutic suicide enzyme/prodrug approaches providing novel means for both safe and effective local therapeutic regimes in solid tumors.200515922474
a flexible peptide linker enhances the immunoreactivity of two copies hbsag pres1 (21-47) fusion protein.pres1 (21-47) region of hbv large surface protein is hepatocyte receptor binding site and the anti-pres1 (21-47) antibody possesses the virus-neutralizing activity and protective effect. it is important to obtain the peptide with higher immunoreactivity on a large scale for detecting the anti-pres1 (21-47) antibody in the sera from hbv infected patients and future vaccine recipients. the expression vector pgex sls, which expressed two copies of the pres1 (21-47) peptide connected by a flexible l ...200414687974
erratum to "characterization and diagnostic potential of hepatitis b virus nucleocapsid expressed in e. coli and p. pastoris".the hepatitis b core antigen (hbcag) was expressed in escherichia coli and in pichia pastoris. a hexa-histidine tag was introduced at the c terminus of the e. coli expressed protein allowing its purification by ni2+-chelate affinity chromatography. the p. pastoris expressed hbcag was isolated following heat treatment. the two recombinant hbcags were purified further on a sucrose gradient. mass spectrometry analysis suggested that hbcag was n-acetylated only in p. pastoris and reaction with ellma ...200211879706
affinity maturation of natural antibody using a chain shuffling technique and the expression of recombinant antibodies in escherichia coli.the affinity of natural antibody (ka = 8 x 10(6) m(-1)) recognizing pres1 of hepatitis b virus (hbv) was improved by replacing the heavy (h) chain gene with repertoires of vh genes, obtained from two nonimmunized donors. two separate clones, 1c2 and 1e4, showed affinities of 2.3 x 10(7) and 5.2 x 10(7) m(-1), which were increased by factors of 2.8 and 6.5, respectively, compared to the parental clone. recombinant scfvs (rscfvs) were expressed as fusion protein with minor coat protein, piii, and ...200010964702
crystal structure of a dominant b-cell epitope from the pres2 region of hepatitis b virus in the form of an inserted peptide segment in maltodextrin-binding protein.we report here the crystal structure of male-b363, a recombinant construction of maltodextrin-binding protein bearing a dominant b-cell epitope sequence from the pres2 region of the hepatitis b surface antigen. the inserted peptide sequence, which replaces the seven carboxy-terminal residues of maltodextrin-binding protein, carries the 14 amino acid residue epitope contained between residues 132 and 145 from the pres2 region. the epitope sequence is flanked on either side by additional residues ...19989654443
the hepatitis b virus x protein is a potent amp kinase.the hepatitis b virus x-protein (hbx) has been expressed in escherichia coli both as an unfused protein and with an n-terminal hexahis-containing fusion sequence. both forms of hbx, after purification, displayed a potent amp kinase activity, in which hbx phosphorylates amp to adp, using atp as the exclusive phosphate donor. we also found that hbx has previously unreported gtpase and gtp-adp nucleoside diphosphate kinase activities.19968627219
capsid assembly and involved function analysis of twelve core protein mutants of duck hepatitis b virus.the roles of different regions of the duck hepatitis b virus (dhbv) core protein on viral capsid assembly and related functions were examined. twelve deletion and insertion mutations which covered 80% of the dhbv c open reading frame were constructed and expressed in escherichia coli. the n-terminal region (amino acids 3 to 66) of dhbv core protein was important for its tertiary structure and function in e. coli. the expressed core mutants without this region apparently inhibited e. coli growth. ...19948254745
comparison of three different recombinant hepatitis b virus core particles expressed in escherichia coli.the properties of three different recombinant hepatitis b virus core proteins expressed in escherichia coli were compared: an n-terminal fusion protein, a c-terminally truncated protein and a sequence-authentic protein. all three proteins assembled into capsid-like particles with typical hbc-antigenicity, sedimentation behavior and distinctive electron microscopical images. apart from this, however, variant hbc proteins displayed properties different from sequence-authentic hbc protein p21.4. un ...19948198438
human hepatitis virus x gene encodes a regulatory domain that represses transactivation of x protein.the human hepatitis b virus (hbv) x gene seems to be essential for establishment of viral infection, and the x gene product, hbx, transactivates virus and host genes through a wide variety of cis-elements, whereas regulation of hbx has not been fully understood. we found that transactivation-negative hbx mutants truncated at the c-terminal portion specifically repressed the hbx transactivation in trans. the ability to trans-repress the hbx transactivation is confined to the n-terminal third of h ...19948195148
three-dimensional structure of hepatitis b virus core particles determined by electron cryomicroscopy.human hepatitis b virus core protein expressed in e. coli assembles into two sizes of particle. we have determined their three-dimensional structures by electron cryomicroscopy and image processing. the large and small particles correspond to triangulation number t = 4 and t = 3 dimer clustered packings, containing 240 and 180 protein subunits, respectively. the local packing of subunits is very similar in the two sizes of particle and shows holes or channels through the shell. the native viral ...19948004680
hepatitis core antigen produced in escherichia coli: subunit composition, conformational analysis, and in vitro capsid assembly.the production and biochemical and physiocochemical analysis are described of recombinant-produced hepatitis b virus core antigen (hbcag capsid) and the corresponding particle produced by a deletion mutant missing the c-terminal 39 residues (hbeag). conditions for producing hbeag from hbcag capsids by in vitro proteolysis are also described. the morphology and masses of these capsids were determined by scanning transmission electron microscopy. both hbcag and hbeag capsids comprise two size clas ...19957711014
restriction map of the hepatitis b virus dna cloned in escherichia coli.a plasmid carrying the complete genome of hepatitis b virus (hbv) inserted into the bamhi site of the pbr322 plasmid vector has been constructed. the physical map of hbv dna established for 13 restriction endonucleases allows to conclude that the cloned dna is similar, but not identical to the hbv dna of ayw subtype.19826299904
production of immunologically active surface antigens of hepatitis b virus by escherichia coli.several plasmids have been constructed which direct the synthesis of hepatitis b virus surface antigens in escherichia coli either as the native polypeptide or fused to other plasmid encoded polypeptides. when injected into rabbits, extracts from bacteria carrying some of these plasmids induced the synthesis of antibodies to the antigens even though the extracts did not give satisfactory positive results in radioimmunoassay for them. either the nh2-terminal segment or the cooh-terminal segment o ...19816170067
hepatitis b virus core particles displaying mycobacterium tuberculosis antigen esat-6 enhance esat-6-specific immune responses.early secreted antigenic target-6 (esat-6), an important mycobacterium tuberculosis t-cell antigen, is an attractive candidate antigen for tuberculosis subunit vaccine development. because esat-6 has a low inherent immunogenicity, we used hepatitis b virus core (hbc) protein as an immune carrier to enhance esat-6 immunogenicity. the esat-6 gene was inserted into the major immunodominant region of the hbc molecule by fusion pcr. the recombinant protein, hbc-esat-6 (he6), was expressed in escheric ...201121689705
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