Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.5 (thrombin)
33,306 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Helicobacter pylori toxin VacA induces intracellular vacuolation and plays an essential role in H. pylori-related diseases. The mature exotoxin is divided into two domains, P37 and P58. A soluble form of VacA fused with GST was expressed in Escherichia coli. Although the soluble fusion lacked vacuolating activity after cleavage by thrombin, it had a binding affinity similar to that of the native VacA. Moreover, it blocked the vacuolating activity induced by the native toxin. Different C-terminal truncated fusions were generated (GST-P72, GST-P53, and GST-P37) and were also produced in a soluble form. A significantly reduced binding activity was seen for GST-P72 and nearly no specific association was detected for GST-P37. Our results suggested that the whole P58 fragment contributed to the cell binding activity in HeLa cells, particularly in the C-terminal approximately 100-residue region.
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PMID:Expression and binding analysis of GST-VacA fusions reveals that the C-terminal approximately 100-residue segment of exotoxin is crucial for binding in HeLa cells. 1109 57

The L1 major capsid proteins of human papillomavirus (HPV) types 11 and 16 were purified and analyzed for structural integrity and in vitro self-assembly. Proteins were expressed in Escherichia coli as glutathione-S-transferase-L1 (GST-L1) fusions and purified to near homogeneity as pentamers (equivalent to viral capsomeres), after thrombin cleavage from the GST moiety and removal of tightly associated GroEL protein. Sequences at the amino and carboxy termini contributing to formation of L1 pentamers and to in vitro capsid assembly were identified by deletion analysis. For both HPV11 and HPV16 L1, up to at least ten residues could be deleted from the amino terminus (Delta N10) and 30 residues from the carboxy terminus (Delta C30) without affecting pentamer formation. The HPV16 pentamers assembled into relatively regular, 72-pentamer shells ("virus-like particles" or VLPs) at low pH, with the exception of HPV16 L1 Delta N10, which assembled into a 12-pentamer, T=1 capsid (small VLP) under all conditions tested. The production of large quantities of assembly-competent L1, using the expression and purification protocol described here, has been useful for crystallographic analysis, and will be valuable for studies of virus-receptor interactions and potentially for vaccine design.
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PMID:Papillomavirus capsid protein expression in Escherichia coli: purification and assembly of HPV11 and HPV16 L1. 1124 12

Recently, two types of estrogen sulfotransferase, chronologically named types 1 and 2 estrogen sulfotransferase (hEST1 and hEST2), have been described. Since hEST2 selectively catalyzes the sulfonation of ethinyl estradiol as well as that of estrone (E1) and estradiol (E2), but poorly the sulfonation of catecholestrogens, we wanted to assess the ability of hEST1 to metabolize these compounds. We overexpressed hEST1 in Escherichia coli in fusion with GST, then purified the enzyme using a glutathione affinity column, and obtained GST-free enzyme by digestion with thrombin. Using [35S]-phosphosadenosine phosphosulfate (PAPS) as cofactor, we showed that hEST1 efficiently metabolizes the transformation of 2-OH-E2 and 2-OH-E1. However, the transformation of 4-OH-E1 and 4-OH-E2 is much less efficient. Our results also show that hEST1 metabolizes more efficiently E2 than E1. Since hEST1 mRNA is produced from the same gene as MPST using different alternative promoters and since it is expressed in most breast cancer cells (MCF-7, ZR-75-1, T47-D, MDA-231, and MDA-418), studies of the expression and activity of hEST1 will be most important to have a better knowledge about its involvement in the control of the genotoxicity of estrogens and catecholestrogens.
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PMID:High metabolization of catecholestrogens by type 1 estrogen sulfotransferase (hEST1). 1135 77

For investigating the DNA binding property of classical zinc finger protein Zif268, an in vivo transcription interference experiment was once utilized to develop a genetic selection assay. By screening a library in which the key amino acids of the third zinc finger from Zif268 were randomized, some single fingers with new binding specificity were obtained. In this study, by combining the single fingers, two three-finger peptides cDNA ZF123 and 2ZF123 were constructed by an over-lap PCR technique using the DNA binding domain of Zif268 as the template. After three times PCR, the products were inserted into pUC18 for cloning. The ZF123 and 2ZF123 cDNA were also inserted into pGEX-2T for expression in Escherichia coli after sequencing confirmation. The result showed that the three-finger peptides were expressed at a high level in E. coli JM109. The fusion protein GST-ZF123/2ZF123 have the relative molecular weight of 34.0 kD and consisted about 20% of the total soluble cell protein as detected by SDS-PAGE. After supersonic treatment, the soluble part of the bacterial extract was purified. After two additional thrombin cleavage and Sepharose 4B affinity purification steps, the free three-fingers peptide proteins were also obtained. The construction and obtaining of the three-fingers peptide cDNA and its products will facilitate the in vivo and in vitro DNA binding specificity study and the design of the hybrid transcription factors.
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PMID:[Constructing and expression of three zinc-fingers peptide with specific DNA recognition property in Escherichia coli]. 1170 97

Active cytosolic (CT) Cu,Zn superoxide dismutase from Schistosoma mansoni (SmCTSOD) was recovered after thrombin cleavage of a glutathione-S-transferase linked fusion protein (GST-SmCTSOD) expressed in the presence of the active-site metals. Crystals have been obtained in two space groups, P2(1)2(1)2(1) and P2(1). The former have unit-cell parameters a = 74.64, b = 78.24, c = 95.18 A and typically diffract to 2.2 A. The monoclinic crystals have unit-cell parameters a = 39.27, b = 95.08, c = 78.41 A, beta = 103.55 degrees and diffract to at least 1.55 A. The calculated solvent content of the crystals is compatible with two dimers of SmCTSOD in the asymmetric unit in both cases. Molecular-replacement solutions have been obtained for both crystal forms and show that slight distortions in the crystal packing relate one form to the other.
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PMID:Expression and preliminary X-ray diffraction studies of cytosolic Cu,Zn superoxide dismutase from Schistosoma mansoni. 1171 3

CD83 is a 45-kDa glycoprotein and member of the immunoglobulin (Ig) superfamily. It is the best known marker for mature dendritic cells. Although the precise function of CD83 is not known, its selective expression and upregulation together with the costimulators CD80 and CD86 suggests an important role of CD83 in the induction of immune responses. To perform functional studies and to elucidate its mode of action it is vital to obtain recombinant expressed and highly purified CD83 molecules. Therefore, the external Ig domain of human CD83 (hCD83ext) was expressed as a GST fusion protein (GST-hCD83ext) and the soluble protein was purified under native conditions. The fusion protein was purified using GSTrap columns followed by anion-exchange chromatography. GST-hCD83ext was then cleaved using thrombin and soluble hCD83ext was further purified using GSTrap columns and finally by a preparative gel filtration as a polishing step and used for further characterization. The purified GST-hCD83 fusion protein was also used to generate monoclonal anti-CD83 antibodies in a rat system. Two different monoclonal antibodies were generated. Using these antibodies, CD83 was specifically recognized in FACS and Western blot analyses. Furthermore, we showed that native CD83 is glycosylated and that this glycosylation influences the binding of the antibodies in Western blot analyses. Finally, the purified hCD83ext protein was analyzed by one-dimensional NMR and these analyses strongly indicate that hCD83ext is folded and could therefore be used for further structural and functional studies.
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PMID:Overexpression, purification, and biochemical characterization of the extracellular human CD83 domain and generation of monoclonal antibodies. 1192 61

Ptd(4,5)P(2) is thought to promote and organize a wide range of cellular functions, including vesicular membrane traffic and cytoskeletal dynamics, by recruiting functional protein complexes to restricted locations in cellular membranes. However, little is known about the distribution of PtdIns(4,5)P(2) in the cell at high resolution. We have used the pleckstrin homology (PH) domain of phospholipase delta(1) (PLCdelta(1)), narrowly specific for PtdIns(4,5)P(2), to map the distribution of the lipid in astrocytoma and A431 cells. We applied the glutathione S-transferase-tagged PLCdelta(1) PH domain (PLCdelta(1)PH-GST) in an on-section labelling approach which avoids transfection procedures. Here we demonstrate PtdIns(4,5)P(2) labelling in the plasma membrane, and also in intracellular membranes, including Golgi (mainly stack), endosomes and endoplasmic reticulum, as well as in electron-dense structures within the nucleus. At the plasma membrane, labelling was more concentrated over lamellipodia, but not in caveolae, which contained less than 10% of the total cell-surface labelling. A dramatic decrease in signal over labelled compartments was observed on preincubation with the cognate headgroup [Ins(1,4,5)P(3)], and plasma-membrane labelling was substantially decreased after stimulation with thrombin-receptor-activating peptide (SFLLRN in the one-letter amino acid code), a treatment which markedly diminishes PtdIns(4,5)P(2) levels. Thus we have developed a highly selective method for mapping the PtdIns(4,5)P(2) distribution within cells at high resolution, and our data provide direct evidence for this lipid at key functional locations.
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PMID:Subcellular localization of phosphatidylinositol 4,5-bisphosphate using the pleckstrin homology domain of phospholipase C delta1. 1196 66

The CtxB gene encoding cholerae toxin subunit B was amplified from Vibrio cholerae genomic DNA by PCR. The result of sequencing indicated that CtxB gene encodes 124 amino acid residues. The sequence of CtxB gene was almost the same as that of reported except for the codon of Thr 62. The expression plasmid pGEX-CTXB was constructed by inserting CtxB gene into plasmid pGEX-4T-2, containing gst gene, immediately downstream of the T7 promoter. The expressed plasmid was introduced into E.coli BL21(DE3) cells and expression strain CTXB/BL21 was selected. SDS-PAGE analysis revealed that the GST-CTXB fusion protein was highly expression and accumulated up to 36% of bacterial soluble proteins after the induction by IPTG. A fusion protein of 40 kD was expressed as inclusion body. The fusion protein was refolded and purified. The purified fusion protein was cut by thrombin to obtain the purified CTXB protein.
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PMID:Cloning of the CtxB Gene of Vibrio cholerae and Its Expression in E.coli. 1209 92

To reveal the possible role of the amino-terminal domain of G protein-coupled receptor kinases(GRKs)in receptor phosphorylation and/or modulation of its kinase activity, a truncated mutant of GRK-2 lacking the amino-terminal domain(deltaN-GRK2)was made. deltaN-GRK2 was expressed effectively in E.coli as a GST fusion protein and was purified by affinity chromatography on a GSH-Sepharose column. deltaN-GRK2 was then separated from GST tag by thrombin cleavage and recovered. Although deltaN-GRK2 had nearly identical activity with wild-type GRK-2 in phosphorylation of peptide substrate, it completely lost the ability to phosphorylate the light-activated receptor rhodopsin. Furthermore, deletion of the amino-terminal domain rendered GRK-2 unresponsive to the regulation of kinase activity by a truncated form of rhodopsin, (329)G-Rho(*) and beta gamma subunits of G protein. These results demonstrated that the amino-terminal domain was necessary to GRK2 for both the phosphorylation of receptor and the regulation of its kinase activity by the receptor. It was reasonable to postulate that this domain has little, if any effect on the catalytic domain of natural form of GRK2.
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PMID:Effects of Deleting the Amino-terminal Domain of GRK-2 on Its Function. 1211 Sep 29

Engineering E. coli strain, BL21 (DE3)/pGEX-4T-human Thymosin alpha 1, was constructed by oligonucleotide annealing and PCR amplifying the target gene, then ligating it with pGEX-4T-3 vector and transferring into BL21 host. The yield of fusion protein of GST-Thymosin alpha 1 expressed from BL21 (DE3)/pGEX-4T-thymosin alpha 1 is about 35%-40% of total protein after fermentation. Following the simple cut of thrombin or CNBr, about 0.2 g/L thymosin alpha 1 can be harvested. The product is checked by MS and activity test, which indicates that the recombinant product has full biological activity of native thymosin alpha 1.
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PMID:[Fusion expression of human thymosin alpha 1 in Escherichia coli]. 1256 Nov 95


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