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

---

Query: EC:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sequence data suggest that Japanese encephalitis virus (JEV) protein NS3 is a multifunctional protein with sequence motifs characteristic of a protease and a helicase. To examine the functions of JEV-NS3, a fusion protein of NS3 in Escherichia coli was generated. Analysis by Western blot using monospecific rabbit antisera generated against the fusion protein (anti-MBJEN3) showed that NS3 was localized in the membrane fraction of JEV-infected cells and the particulate fraction of bacteria extracts. The addition of anti-MBJEN3 sera reduced JEV-specific RNA synthesis activity in a in vitro system. In addition, NS3 was shown to exhibit RNA binding and ATPase activities, suggesting this protein has an important role in viral RNA replication in virus-infected cells.
...
PMID:Japanese encephalitis virus nonstructural protein NS3 has RNA binding and ATPase activities. 773 56

The involvement of intracellular acidic vesicles in the early phase of Japanese encephalitis (JE) virus infection in Vero cells was observed by adding a specific vacuolar type H+-ATPase (V-ATPase) inhibitor (bafilomycin A1) in the cell culture medium. Studies with the detection of viral envelope (E) protein suggested that bafilomycin A1 inhibited virus infection in the cells. Subcellular distribution of incoming biotinylated virions and 3H-uridine-labeled viral RNA were observed in fractions of a Percoll density gradient. At 10 min of the chasing period, virions and viral RNA were found mainly in fractions with a mean density of 1.04 g/ml corresponding to the endosome both in the control and bafilomycin A1-treated cells. At 60 min of the chasing period, the peak of biotin activity was detected in fractions with a mean density of 1.08 g/ml corresponding to the lysosome, whereas the peak of radioactivity did not run parallel with that of biotin and shifted to fractions with a mean density of 1.05 g/ml and higher than 1.084 g/ml, respectively. At 60 min of the chasing period in bafilomycin A1-treated cells, the peak of biotin and radioactivity were still found mainly in the fraction with a density of 1.04 g/ml, representing the endosome. Subcellular fractionation by a Percoll density gradient revealed that bafilomycin A1 treatment resulted in the accumulation of virions in the endosome fraction and suggested the prevention of intracellular translocation of the virions which occurs during the early entry process of an infecting virus to the cells.
...
PMID:Japanese encephalitis virus infection in Vero cells: the involvement of intracellular acidic vesicles in the early phase of viral infection was observed with the treatment of a specific vacuolar type H+-ATPase inhibitor, bafilomycin A1. 927 99

The Ilheus (ILH) virus has long been known to belong to group B of the arboviruses. Previous attempts to relate it to existing serogroups within the Flavivirus genus using conventional serological techniques such as hemagglutination inhibition, neutralization and complement fixation tests have been inconclusive. We have first used denaturing gel electrophoresis to estimate the molecular weight of immunoprecipitated radiolabeled viral proteins and the cross-reactivity among ILH proteins and hyperimmune sera to several flaviviruses only from the mosquito-borne encephalitis virus serogroups. The estimated molecular weight for the three proteins was in the same order of magnitude, as previously established, for mosquito-borne flaviviruses. Cross-immunoprecipitation tests showed that NS3 protein is the most cross-reactive. Partial nucleotide sequence analyses of the NS3 gene, corresponding to an area linking the helicase and the RNA triphosphatase domains, revealed that ILH virus is very closely related to the Japanese encephalitis virus complex confirming earlier serological data.
...
PMID:Ilheus virus (Flaviviridae, Flavivirus) is closely related to Japanese encephalitis virus complex. 961 22

Involvement of intracellular acidic compartments in the early phase of Japanese encephalitis (JE) virus infection of C6/36 mosquito cells was examined by bafilomycin A1, a specific inhibitor of vacuolar type H(+)-ATPase (V-ATPase). Dose dependent reduction of viral envelope protein (E) produced into the infected culture fluid was observed by pretreating the cells with 0.25 to 1.0 microM bafilomycin A1. In synchronized infection, cell surface-bound virions were internalized immediately by heating at 31 degrees C, followed by the release of nucleocapsid into the cytosol within a short lag period. Subcellular distribution of infecting 3H-uridine-labeled viral RNA (V-RNA) and its RNase sensitivity were analyzed by fractionation in Percoll density gradient centrifugation. At a 10 min chasing period, an RNase resistant V-RNA peak was found in fractions with a mean density of 1.05 g/ml corresponding to the endosome, while an RNase sensitive V-RNA peak was detected at density range of 1.052-1.054 g/ml corresponding to the ribosome in C6/36 cell homogenate. The results indicate that JE virus infection in C6/36 cells proceeded through the endocytic pathway involving intracellular acidic compartments which was affected by bafilomycin A1.
...
PMID:Effects of bafilomycin A1 on Japanese encephalitis virus in C6/36 mosquito cells. 973 34

The NS3 protein of Japanese encephalitis virus (JEV) contains motifs typical of RNA helicase/NTPase but no RNA helicase activity has been reported for this protein. To identify and characterize the RNA helicase activity of JEV NS3, a truncated form of the protein with a His-tag was expressed in Escherichia coli and purified. The purified JEV NS3 protein showed an RNA helicase activity, which was dependent on divalent cations and ATP. An Asp-285-to-Ala substitution in motif II of the JEV NS3 protein abolished the ATPase and RNA helicase activities. These results indicate that the C-terminal 457 residues are sufficient to exhibit the RNA helicase activity of JEV NS3.
...
PMID:Identification and characterization of the RNA helicase activity of Japanese encephalitis virus NS3 protein. 1062 Jul 9

The role of the conserved DExH motif of the Japanese encephalitis virus (JEV) NS3 protein in the ATPase and RNA helicase activities was compared with that of the hepatitis C virus (HCV) NS3 protein. In the DExH motif of JEV NS3, Asp-285 and Glu-286 were essential for both ATPase and RNA helicase activities. Cys-287 was critical for the RNA helicase activity of JEV NS3 but not for ATPase activity. A His-288-to-Ala substitution in the DExH motif of HCV NS3 resulted in an increase in ATPase activity which was suppressed by poly(U). In contrast, alanine substitution at the same site in JEV NS3 did not increase basal ATPase activity which remained to be stimulated by poly(U). Thus, the mutational effect at His in motif II was different in the HCV and JEV NS3 proteins. Mutagenesis at His-288 of JEV NS3 revealed that His was the most preferable amino acid for ATPase activity and Ala, Gly, Asn, Gln, Ser, or Arg could partly substitute for it. However, any other mutation at His-288 completely disrupted the RNA helicase activity of JEV NS3. The results suggest that Cys-287 and His-288 are essential residues especially for the RNA helicase activity of JEV NS3 and the ATPase and helicase activities are separable enzymatic functions.
...
PMID:Role of the DExH motif of the Japanese encephalitis virus and hepatitis C virus NS3 proteins in the ATPase and RNA helicase activities. 1091 2

A series of ring-expanded ("fat") heterocycles, nucleoside and nucleotide analogues (RENs) containing the imidazo[4,5-e][1,3]diazepine ring system (9, 14, 15, 18, 24-26, 28, 31, and 33) and imidazo[4,5-e][1,2,4]triazepine ring systems (30b, 30c, 32, and 34), have been synthesized as potential inhibitors of NTPases/helicases of Flaviviridae, including the West Nile virus (WNV), hepatitis C virus (HCV), and Japanese encephalitis virus (JEV). An amino-terminal truncated form of human enzyme Suv3(delta1-159) was also included in the study so as to assess the selectivity of RENs against the viral enzymes. The analogues of RENs included structural variations at position 1 of the heterocyclic base and contained changes in both the type of sugar moieties (ribo, 2'-deoxyribo, and acyclic sugars) and the mode of attachment (alpha versus beta anomeric configuration) of those sugars to the heterocyclic base. The target RENs were biochemically screened separately against the helicase and ATPase activities of the viral NTPases/helicases. A number of RENs inhibited the viral helicase activity with IC50 values that ranged in micromolar concentrations and exhibited differential selectivity between the viral enzymes. In view of the observed tight complex between some nucleosides and RNA and/or DNA substrates of a helicase, the mechanism of action of RENs might involve their interaction with the appropriate substrate through binding to the major or minor groove of the double helix. The REN-5'-triphosphates, on the other hand, did not influence the above unwinding reaction, but instead exerted the inhibitory effect on the ATPase activity of the enzymes. The activity was found to be highly dependent upon the low concentration levels of the substrate ATP. At concentrations >500 microM of RENs and the ATP concentrations >10 times the Km value of the enzyme, a significant activation of NTPase activity was observed. This activating effect underwent further dramatic enhancement (>1000%) by further increases in ATP concentration in the reaction mixture. A tentative mechanistic model has been proposed to explain the observed results, which includes an additional allosteric binding site on the viral NTPases/helicases that can be occupied by nucleoside/nucleotide-type molecules such as RENs.
...
PMID:Ring-expanded ("fat") nucleoside and nucleotide analogues exhibit potent in vitro activity against flaviviridae NTPases/helicases, including those of the West Nile virus, hepatitis C virus, and Japanese encephalitis virus. 1295 67

5'-O-(4-fluorosulphonylbenzoyl)-esters of ribavirin (FSBR), adenosine (FSBA), guanosine (FSBG) and inosine (FSBI) were obtained by acylation of the 5'-OH of adenosine, guanosine, inosine, and ribavirin with 4-fluorosulphonylbenzoyl chloride (FSBCI) in HMPA. The above derivatives were tested as inhibitors of nucleoside triphosphatase (NTPase)/helicase activities of Flaviviridae: hepatitis C virus (HCV), West Nile virus (WNV), Japanese encephalitis virus (JEV) and dengue virus (DENV) and polymerase activity of HCV and WNV. When the unwinding activity of viral NTPase/helicases was tested under standard conditions, only weak inhibition was obtained with FSBI (IC50 > or = 120 microM) and in the case of FSBG even an activation was seen. The preincubation of the NTPase/helicases with the 5'-O-FSB derivatives increased the inhibitory effect. Screening of the 5'-O-FSB derivatives on inhibition of the WNV and HCV RNA polymerases employing GTP or UTP substrates revealed rather modest inhibitory effect. FSBI exhibited the highest inhibitory activity against WNV (IC50 = 70 microM with UTP substrate) and HCV polymerase (IC50 = 80 microM with GTP substrate). Other 5'-O-FSB derivatives were very weak inhibitors or completely failed to show any activity against HCV and WNV enzymes. In contrast to the NTPase/helicases the preincubation of the polymerases did not influence the inhibition.
...
PMID:Synthesis and evaluation of ATP-binding site directed potential inhibitors of nucleoside triphosphatases/helicases and polymerases of hepatitis C and other selected Flaviviridae viruses. 1507 13

Hsp70 potentiates specific immune responses to some antigenic peptides fused to it. A recombinant hsp70 protein expression vector in methylotrophic yeast, Pichia pastoris, was developed that fused the major antigenic segment of Japanese encephalitis virus (JEV) E protein to the amino terminus of Mycobacterium tuberculosis hsp70. The C-terminal peptide binding domain of hsp70 stimulated Th1-polarizing cytokines, CC chemokines and an adjuvant effect. However, the N-terminal ATPase domain (hsp70 1-358) failed to stimulate any of these cytokines or chemokines. Based on these data, a vector was constructed that permits the fusion of major antigenic segment of E protein to the amino terminus of peptide binding domain of hsp70. Antibody titers, lymphocytes proliferation, the level of mIL-2 or mIFN-gamma and neutralizing antibodies in immunized mice showed that antigenicity of E-binding domain fusion protein was almost as effective as E-hsp70 fusion protein and more effective than carrier protein hsp70 alone. In eliciting a humoral and cellular immune response, both fusion proteins were more powerful than the major antigenic segment of E protein alone, but less effective than the segment administered with Freund's adjuvant.
...
PMID:Fusion expression of major antigenic segment of JEV E protein-hsp70 and the identification of domain acting as adjuvant in hsp70. 1685 55

Japanese encephalitis virus (JEV) formed plaques in mosquito C6/36 cell layers after adsorption on the cell surface and exposure to pH values lower than 6.2. The number of plaques decreased within pH ranges from 7.4 to 6.4, but increased within pH ranges from 6.2 to 5.8. Plaque formation was prevented by treatment of the virus with a JEV-neutralizing monoclonal antibody, 503, after virus adsorption. Plaque formation was not affected by pretreatment with a specific V-ATPase inhibitor, bafilomycin A1. The results indicate that JEV successfully fused with the C6/36 cell membrane under acidic conditions below pH 6.2, which in turn led to plaque formation in C6/36 cell layers. These results suggest that productive JEV infection occurs at the C6/36 cell surface via the fusion between JEV and the cell membrane.
...
PMID:Plaque formation by Japanese encephalitis virus bound to mosquito C6/36 cells after low pH exposure on the cell surface. 1751 44


1 2 Next >>

---