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)

A sedimentable complex of enzymes for DNA synthesis was partially purified from the combined low-salt nuclear extract-postmicrosomal supernatant solution of HeLa cell homogenates by poly(ethylene glycol) precipitation in the presence of 2 M KCl, discontinuous gradient centrifugation, Q-Sepharose chromatography, and velocity gradient centrifugation. In addition to the previously described 640-kDa multiprotein DNA polymerase alpha-primase complex [Vishwanatha et al. (1986) J. Biol. Chem. 261, 6619-6628], the enzyme complex also has associated topoisomerase I, DNA-dependent ATPase, RNase H, DNA ligase, a simian virus 40 origin recognition, dA/dT sequence binding protein [Malkas & Baril (1989) Proc. Natl. Acad. Sci. U.S.A. 86, 70-74], and proliferating cell nuclear antigen. Essentially all of the T antigen dependent simian virus 40 in vitro replication activity in the combined nuclear extract-postmicrosomal supernatant solution resides with the sedimentable complex of enzymes for DNA synthesis. Sedimentation analysis on a 10-35% glycerol gradient in the presence of 0.5 M KCl indicates that the enzyme complex is 21S. The associated enzymes for DNA synthesis and in vitro simian virus 40 replication activity cofractionate throughout the purification of the 21S complex. The DNA polymerase and in vitro simian virus 40 replication activities are both inhibited by monoclonal antibody (SJK 132-20) to human DNA polymerase alpha and by 5-10 microM butylphenyl-dGTP, indicating that the association of DNA polymerase alpha with the 21S enzyme complex is essential for the initiation of SV40 DNA replication in vitro.
...
PMID:A 21S enzyme complex from HeLa cells that functions in simian virus 40 DNA replication in vitro. 216 68

To determine the contribution that DNA polymerase alpha makes to the overall DNA replication fidelity in mammalian systems, we measured the fidelity of replication of the SV40-based shuttle vector, pZ189, in a reconstituted in vitro DNA replication system which contained purified HeLa DNA polymerase alpha (in addition to single-stranded DNA binding protein, topoisomerase II, DNA ligase, 5'----3' exonuclease, ribonuclease H, and SV40 T-antigen). We found that DNA polymerase alpha is highly accurate when carrying out bidirectional replication in this system. This high fidelity of replication by DNA polymerase alpha in the reconstituted replication system contrasts with a relatively low fidelity of gap-filling DNA synthesis on the same target gene by purified HeLa cell DNA polymerase alpha in the absence of other replication factors. The fidelity of DNA replication by DNA polymerase alpha, although relatively high in the reconstituted system, is about 4-fold lower than DNA replication in a crude HeLa cell extract which contains additional replication factors including DNA polymerase delta. These results demonstrate that DNA polymerase alpha has the capacity to replicate DNA with high fidelity when carrying out semiconservative DNA replication in a minimal reconstituted replication system, but additional cellular factors not present in the reconstituted system may contribute to the higher replication fidelity of the crude system.
...
PMID:DNA polymerase alpha from HeLa cells synthesizes DNA with high fidelity in a reconstituted replication system. 221 24

We have purified to homogeneity the primer recognition proteins (PRP) from human HeLa cells. PRP is associated with DNA polymerase alpha complex in HeLa cells. Purified PRP is free of DNA polymerases alpha, beta, and delta, deoxyribonuclease, DNA primase, ATPase, topoisomerase, and DNA ligase activities. The protein structure of the PRP was defined by sodium dodecyl sulfate gel electrophoresis, which revealed two polypeptides of 36,000 Da (PRP 1) and 41,000 Da (PRP 2). The two polypeptides are associated in a complex in the native state. The Stokes radius of the PRP complex by gel filtration is 40.5 A and the sedimentation coefficient in glycerol gradients is 5.7 S. Purified PRP, which exhibits no DNA polymerase activity, completely restores the activity of DNA polymerase alpha on templates with low primer to template ratios such as heat-denaturated DNA, poly(dA)-oligo(dT), and singly primed M13 single-stranded DNA. Experiments using various amounts of PRP, DNA polymerase alpha, and DNA indicate that a concentration dependence exists between these components in the DNA replication process. Amino acid composition analysis indicates that the PRP is rich in hydrophobic amino acids.
...
PMID:Purification and characterization of primer recognition proteins from HeLa cells. 236 57

The Escherichia coli rho 026 mutation that alters the transcription termination protein Rho prevents growth of wild-type bacteriophage T4. Among the consequences of this mutation are delayed and reduced T4 DNA replication. We show that these defects can be explained by defective synthesis of certain T4 replication-recombination proteins. Expression of T4 gene 41 (DNA helicase/primase) is drastically reduced, and expression of T4 genes 43 (DNA polymerase), 30 (DNA ligase), 46 (recombination nuclease), and probably 44 (DNA polymerase-associated ATPase) is reduced to a lesser extent. The compensating T4 mutation goF1 partially restores the synthesis of these proteins and, concomitantly, the synthesis of T4 DNA in the E. coli rho mutant. From analyzing DNA synthesis in wild-type and various multiply mutant T4 strains, we infer that defective or reduced synthesis of these proteins in rho 026-infected cells has several major effects on DNA replication. It impairs lagging-strand synthesis during the primary mode of DNA replication; it delays and depresses recombination-dependent (secondary mode) initiation; and it inhibits the use of tertiary origins. All three T4 genes whose expression is reduced in rho 026 cells and whose upstream sequences are known have a palindrome containing a CUUCGG sequence between the promoter(s) and ribosome-binding site. We speculate that these palindromes might be important for factor-dependent transcription termination-antitermination during normal T4 development. Our results are consistent with previous proposals that the altered Rho factor of rho 026 may cause excessive termination because the transcription complex does not interact normally with a T4 antiterminator encoded by the wild-type goF gene and that the T4 goF1 mutation restores this interaction.
...
PMID:Impaired expression of certain prereplicative bacteriophage T4 genes explains impaired T4 DNA synthesis in Escherichia coli rho (nusD) mutants. 254 60

A DNA ligase has been purified approximately 2,100-fold, to near-homogeneity, from Drosophila melanogaster 6-12-h embryos and was shown to catalyze the formation of 3',5'-phosphodiester bonds. Polypeptides with molecular weights 83,000, 75,000, and 64,000 were observed when the purified enzyme was electrophoresed under denaturing conditions. These polypeptides were shown by partial proteolysis studies and two-dimensional gel analysis to be structurally related. The two smaller polypeptides were presumably derived from the largest, 83,000 molecular weight protein, by proteolysis during purification or in vivo. All three polypeptides formed enzyme-adenylylate complexes in the absence of DNA. Drosophila DNA ligase had a Stokes radius of 45 A, a sedimentation coefficient of 4.3 S, and a frictional ratio of 1.6, yielding a calculated molecular weight of 79,800. These studies indicate that DNA ligase from Drosophila embryos is a monomer. The purified ligase was free of detectable ATPase, nuclease, topoisomerase, and DNA polymerase activities. The enzyme exhibited an absolute requirement for ATP in the joining reaction. A divalent metal was required and N-ethylmaleimide inhibited the reaction. Formation of phosphodiester bonds by Drosophila ligase required the presence of 5'-phosphoryl and 3'-hydroxyl termini. The purified enzyme restored biological activity to endonucleolytically cleaved pBR322 DNA. The specific activity of Drosophila DNA ligase was highest in unfertilized eggs. Developing embryos had 5-10-fold more ligase activity than at any later time in development.
...
PMID:DNA ligase from Drosophila melanogaster embryos. Purification and physical characterization. 309 38

In addition to the previously described deoxyribonucleic acid (DNA) polymerase, DNA ligase, DNA exonuclease, and DNA endonuclease activities, purified virions of Schmidt-Ruppin strain of Rous sarcoma virus (SRV) have nucleotides and nucleotide kinase, phosphatase, hexokinase, and lactate dehydrogenase activities. The SRV virions have no glucose-6-phosphate dehydrogenase activity. All enzyme activities, but glucose-6-phosphate dehydrogenase and adenosine triphosphatase, were increased by disruption of the virions. The DNA polymerase, DNA ligase, and hexokinase activities had a higher specific activity in purified virion cores. It is suggested that during assembly virions of SRV may pick up cytoplasmic components which bind to virion proteins. The role of these components in viral replication is not known at present.
...
PMID:Enzymes and nucleotides in virions of Rous sarcoma virus. 433 49

Essentially all of the DNA polymerase alpha activity in CV-1 monkey cells could be extracted as an enzyme complex that used DNA substrates with a low primer:template ratio, such as denatured DNA, at least 25 times more efficiently than did purified alpha polymerase. This form of the enzyme was rapidly dissociated either by the nonionic detergent Triton X-100 or by chromatography on phosphocellulose to generate alpha polymerase and its protein cofactor complex, C1C2. Both alpha polymerase and C1C2 were then independently purified free of deoxyribonuclease, RNA polymerase, DNA ligase, and ATPase activities, and the C1C2 complex was shown to consist of at least two proteins. Purified C1C2, which exhibited no DNA polymerase activity, completely restored the ability of alpha polymerase to use denatured DNA. Although high concentrations of denatured DNA inhibited the activity of C1C2, which binds tightly to single-stranded but not double-stranded DNA, low concentrations catalyzed reconstitution of alpha polymerase with C1C2. The resulting enzyme complex was chromatographically distinct from alpha polymerase on DEAE-Bio-Gel, was no longer dependent upon addition of C1C2 in order to utilize denatured DNA as effectively as DNase I-activated DNA, and was not inhibited by high concentrations of denatured DNA. These properties of the purified reconstituted enzyme were indistinguishable from those native alpha X C1C2-polymerase.
...
PMID:Preparation of DNA polymerase alpha X C1C2 by reconstituting DNA polymerase alpha with its specific stimulatory cofactors, C1C2. 688 71

Homologous recombination is a fundamental biological process. Biochemical understanding of this process is most advanced for Escherichia coli. At least 25 gene products are involved in promoting genetic exchange. At present, this includes the RecA, RecBCD (exonuclease V), RecE (exonuclease VIII), RecF, RecG, RecJ, RecN, RecOR, RecQ, RecT, RuvAB, RuvC, SbcCD, and SSB proteins, as well as DNA polymerase I, DNA gyrase, DNA topoisomerase I, DNA ligase, and DNA helicases. The activities displayed by these enzymes include homologous DNA pairing and strand exchange, helicase, branch migration, Holliday junction binding and cleavage, nuclease, ATPase, topoisomerase, DNA binding, ATP binding, polymerase, and ligase, and, collectively, they define biochemical events that are essential for efficient recombination. In addition to these needed proteins, a cis-acting recombination hot spot known as Chi (chi: 5'-GCTGGTGG-3') plays a crucial regulatory function. The biochemical steps that comprise homologous recombination can be formally divided into four parts: (i) processing of DNA molecules into suitable recombination substrates, (ii) homologous pairing of the DNA partners and the exchange of DNA strands, (iii) extension of the nascent DNA heteroduplex; and (iv) resolution of the resulting crossover structure. This review focuses on the biochemical mechanisms underlying these steps, with particular emphases on the activities of the proteins involved and on the integration of these activities into likely biochemical pathways for recombination.
...
PMID:Biochemistry of homologous recombination in Escherichia coli. 796 21

An ATP-dependent DNA helicase has been purified to near homogeneity from pea chloroplasts. The enzyme is a homodimer of 68-kDa subunits. The purified enzyme shows DNA-dependent ATPase activity and is devoid of DNA polymerase, DNA topoisomerase, DNA ligase or nuclease activities. The enzyme requires Mg2+ or Mn2+ for its maximum activity. ATP is the most favoured cofactor for this enzyme while other NTP or dNTP are poorly utilized. Pea chloroplast DNA helicase can unwind a 17-bp duplex whether it has unpaired single-stranded tails at both the 5' end and 3' end, at the 5' end or at the 3' end only, or at neither end. However, it fails to act on a blunt-ended 17-bp duplex DNA. The enzyme moves unidirectionally from 3' to 5' along the bound strand. The unwinding activity is inhibited by the intercalating drugs nogalamycin and daunorubicine.
...
PMID:Purification and characterization of a DNA helicase from pea chloroplast that translocates in the 3'-to-5' direction. 866 52

The iridovirus isolate termed cricket iridovirus (CrIV) was isolated in 1996 from Gryllus campestris L. and Acheta domesticus L. (both Orthoptera, Gryllidae). CrIV DNA shows distinct DNA restriction patterns different from those known for Insect iridescent virus type 6 (IIV-6). This observation led to the assumption that CrIV might be a new species within the family Iridoviridae. CrIV can be transmitted perorally to orthopteran species, resulting in specific, fatal diseases. These species include Gryllus bimaculatus L. and the African migratory locust Locusta migratoria migratorioides (Orthoptera, Acrididae). Analysis of genomic and host range properties of this isolate was carried out in comparison to those known for IIV-6. Host range studies of CrIV and IIV-6 revealed no differences in the peroral susceptibility in all insect species and developmental stages tested to date. Different gene loci of the IIV-6 genome were analyzed, including the major capsid protein (274L), thymidylate synthase (225R), an exonuclease (012L), DNA polymerase (037L), ATPase (075L), DNA ligase (205R) and the open reading frame 339L, which is homologous to the immediate-early protein ICP-46 of frog virus 3. The average identity of the selected viral genes and their gene products was found to be 95.98 and 95.18% at the nucleotide and amino acid level, respectively. These data led to the conclusion that CrIV and IIV-6 are not different species within the Iridoviridae family and that CrIV must be considered to be a variant and/or a novel strain of IIV-6.
...
PMID:Comparative analysis of the genome and host range characteristics of two insect iridoviruses: Chilo iridescent virus and a cricket iridovirus isolate. 1180 40


1 2 Next >>

---