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

The complete cDNA sequence corresponding to the rapeseed atp6 gene transcript (coding for subunit 6 of F0-ATPase) has been determined by a method involving cDNA synthesis, using specific oligonucleotides as primers, followed by PCR amplification, cloning and sequencing of the amplification products. Only one modification, a C-to-U conversion, has been found when compared to the genomic mitochondrial DNA sequence. Comparison of the extent and frequency of RNA editing of the pol cytoplasmic male sterile (cms) atp6 transcript with those of normal atp6 transcript indicates that there is no variation between the editing status of the atp6 transcripts from pol cms and normal cytoplasms.
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PMID:RNA editing of atp6 transcripts from male-sterile and normal cytoplasms of rapeseed (Brassica napus L.). 139 57

Activator 1 (A1) is a multiprotein complex which is essential for proliferating cell nuclear antigen (PCNA)-dependent DNA polymerase delta (pol delta) activity and efficient in vitro DNA synthesis in the SV40 dipolymerase replication system. In this report, we describe the isolation of A1 from HeLa cytosolic extracts. A1 stimulated pol delta activity in singly primed phi X174 DNA or (dA)4500.oligo(dT)12-18 in reactions containing PCNA, single-stranded DNA binding protein (SSB), and ATP. Using this assay, A1 has been extensively purified. Purified preparations contained five discrete subunits of 145, 40, 38, 37, and 36.5 kDa. ATP hydrolysis to ADP and Pi is essential for A1-dependent pol delta activity, and we have shown that A1 contains an intrinsic ATPase which is stimulated by DNA. The DNA-dependent hydrolysis of ATP can be stimulated by PCNA and further activated by PCNA plus the human single-stranded DNA binding protein. These stimulatory effects were observed with (dA)4500.oligo(dT)12-18, but were not detected with each poly-deoxynucleotide alone. Furthermore, A1 formed a complex with (dA)4500.oligo(dT)12-18 which could be measured by nitrocellulose binding. No complex with (dA)4500 or oligo(dT)12-18 alone was detected by this procedure. Data are also presented which indicate that A1, in conjunction with PCNA, functions as a primer-recognition factor for pol delta, increasing its ability to utilize low levels of primer ends, but it does not increase the size of the DNA products. A1 also markedly reduced the amount of PCNA required for pol delta activity on a multiply primed DNA suggesting that PCNA interacts with A1 at the primer end. These multiple effects of A1 closely resemble the properties of the multisubunit protein RF-C described by Tsurimoto and Stillman (Tsurimoto, T., and Stillman, B. (1990) Proc. Natl. Acad. Sci. U.S.A. 87, 1023-1027).
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PMID:Studies on the activator 1 protein complex, an accessory factor for proliferating cell nuclear antigen-dependent DNA polymerase delta. 167 Jul 72

Eukaryotic DNA polymerase delta and its accessory proteins are essential for SV40 DNA replication in vitro. A multi-subunit protein complex, replication factor C (RF-C), which is composed of subunits with apparent molecular weights of 140,000, 41,000, and 37,000, has primer/template binding and DNA-dependent ATPase activities. UV-cross-linking experiments demonstrated that the Mr = 140,000 subunit recognizes and binds to the primer-template DNA, whereas the Mr = 41,000 polypeptide binds ATP. Assembly of a replication complex at a primer-template junction has been studied in detail with synthetic, hairpin DNAs. Following glutaraldehyde fixation, a gel shift assay demonstrated that RF-C alone forms a weak binding complex with the hairpin DNA. Addition of ATP or its nonhydrolyzable analogue, ATP gamma S, increased specific binding to the DNA. Footprinting experiments revealed that RF-C recognizes the primer-template junction, covering 15 bases of the primer DNA from the 3'-end and 20 bases of the template DNA. Another replication factor, proliferating cell nuclear antigen (PCNA) binds to RF-C and the primer-template DNA forming a primer recognition complex and extends the protected region on the duplex DNA. This RF-C.PCNA complex has significant single-stranded DNA binding activity in addition to binding to a primer-template junction. However, addition of another replication factor, RF-A, completely blocked the nonspecific, single-stranded DNA binding by the RF-C.PCNA complex. RF-A therefore functions as a specificity factor for primer recognition. In the absence of RF-C, DNA polymerase delta (pol delta) and PCNA form a complex at the primer-template junction, protecting exactly the same site as the primer recognition complex. Addition of RF-C to this complex produced a higher order complex which is unstable unless its formation is coupled with translocation of pol delta. These results suggest that the sequential binding of RF-C, PCNA, and pol delta to a primer-template junction might directly account for the initiation of leading strand DNA synthesis at a replication origin. We demonstrate this directly in an accompanying paper (Tsurimoto, T., and Stillman, B. (1991) J. Biol. Chem. 266, 1961-1968).
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PMID:Replication factors required for SV40 DNA replication in vitro. I. DNA structure-specific recognition of a primer-template junction by eukaryotic DNA polymerases and their accessory proteins. 167 Oct 45

It has been clarified that basic mechanism of deoxyribonucleic acid (DNA) replication is conserved from bacteria to higher cells. What distinguishes prokaryotic and eukaryotic modes of DNA replication most clearly is that bacterial chromosomes form a single replicon copied from a single initiation point and eukaryotic chromosomes consist of multiple replicons that initiate at multiple points. Thus, eukaryotes have to coordinate orderly replication of the genome. In order to understand this complex problem as a whole, three approaches were chosen. First approach is a genetic one. Certain number of temperature-sensitive (ts) mutants were isolated from mouse FM3A cells. One of the ts mutants, designated as tsFT20, was shown to contain heat-labile DNA polymerase alpha (pol. alpha). By the use of this mutant strain, it was proved that pol. alpha is essential for mammalian DNA replication. In addition, the human gene for pol. alpha on the X chromosome was assigned. Second approach is an enzymological one. FM3A cells were used for the identification and characterization of enzymes and proteins supposed to be involved in DNA replication. Four DNA-dependent ATPases, three pol. alpha stimulation factors, DNA topoisomerases I and II have been identified, as well as a stimulation factor for the assembly of nucleosome. DNA helicase activity was detected in two of the DNA-dependent ATPase (B and C1). Third approach is the reconstitution of DNA replication in cell-free system. By use of polyoma virus DNA as a template, cell-free extract from FM3A cells supported DNA replication in the presence of polyoma virus large T-antigen. This cell-free system will be useful for the analysis of the function of replication enzymes and proteins as well as the characterization of ts mutants.
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PMID:[Genetic and biochemical studies on the mechanism of mammalian chromosome replication]. 255 87

Liver and brain mitochondrial ATPase activities in rats exposed to high ambient temperature. Acta physiol. pol., 1985, 36 (3): 185-192. Rat liver and brain mitochondrial ATPase activities were investigated after a single exposure (6 h) of the animals to temperatures of 21 degrees, 28 degrees and 37 degrees C. An increase of ATPase activity stimulated by Ca++ ions was noted in the mitochondrial fractions of the liver at 28 degrees C and of the brain at 28 degrees and 37 degrees C. Only in liver mitochondria of rats exposed to 28 degrees C a depression of Mg++-ATPase activity was found.
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PMID:Liver and brain mitochondrial ATPase activities in rats exposed to high ambient temperature. 294 38

DNA polymerase III holoenzyme (holenzyme) has an ATPase activity elicited only by a primed DNA template. Reaction of preformed ATP.holoenzyme complex with a primed template results in hydrolysis of the ATP bound to the holoenzyme, release of ADP and Pi, and formation of an initiation complex between holoenzyme and the primed template. Approximately two ATP molecules are hydrolyzed for each initiation complex formed, a value in keeping with the number bound in the ATP.holoenzyme complex. The possibility that the latter and the initiation complex contain two holoenzyme molecules is supported by the presence of two beta monomers in the initiation complex. Holoenzyme action in the absence of ATP resembles that of pol III (the holoenzyme core) or DNA polymerase III (holoenzyme lacking the beta subunit), with or without ATP, in sensitivity to salt and in processivity of elongation. The initiation complex formed by ATP-activated holoenzyme resists a level of KCl (150 mM) that completely inhibits nonactivated holoenzyme and the incomplete forms of the holoenzyme, and displays a processivity at least 20 times greater. Upon completing replication of available template, holoenzyme can dissociate and form an initiation complex with another primed template, provided ATP is available to reactivate the holoenzyme. By inference, no essential subunits are lost in the cycle of initiation, elongation and dissociation.
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PMID:ATP activation of DNA polymerase III holoenzyme from Escherichia coli. II. Initiation complex: stoichiometry and reactivity. 674 41

The DNA polymerase III (pol III)holoenzyme is the 10 subunit replicase of Escherichia coli. The 71 kDa tau subunit, encoded by dnaX, dimerizes the core polymerase (alpha epsilon theta) to form pol III'[(alpha epsilon theta)2 tau 2]. tau is also a single-stranded DNA-dependent ATPase and can substitute for the gamma subunit during initiation complex formation. We show here that tau also possesses a DNA-DNA and RNA-DNA annealing activity that is stimulated by Mg2+, but neither requires ATP nor is inhibited by non-hydrolyzable ATP analogs. This suggests the tau may act to stabilize the primer-template interaction during DNA replication.
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PMID:DNA and RNA-DNA annealing activity associated with the tau subunit of the Escherichia coli DNA polymerase III holoenzyme. 753 62

Proliferating cell nuclear antigen (PCNA) is essential for eukaryotic DNA replication and functions as a processivity factor of DNA polymerase delta (pol delta). Due to the functional and structural similarity with the beta-subunit of Escherichia coli DNA polymerase III, it has been proposed that PCNA would act as a molecular clamp during DNA synthesis. By site-directed mutagenesis and biochemical analyses, we have studied the functional domains of human PCNA required for stimulation of replication factor C (RF-C) ATPase and DNA synthesis by pol delta. Short deletions from either the N or C termini caused drastic changes in extraction and chromatographic behaviors, suggesting that both of these terminal regions are crucial to fold the tertiary structure of PCNA. The short C-terminal stretch from Lys254 to Glu256 is necessary for stimulation of RF-C ATPase activity, but not for stimulation of DNA synthesis by pol delta. Nine basic amino acids that are essential for activating DNA synthesis by pol delta are positioned at the internal alpha-helices of PCNA. This result is in good agreement with the observation that PCNA has a ring structure similar to the beta-subunit and clamps a template DNA through this positively charged internal surface. Several other charged amino acids are also required to stimulate either RF-C ATPase or pol delta DNA synthesis. Some of them are positioned at loops which are exposed on one of the side surface of PCNA adjacent to the C-terminal loop. In addition, the beta-sheets composing the intermolecular interface of the trimeric PCNA are important for interaction with pol delta. Therefore, the outer surface of PCNA has multiple functional surfaces which are responsible for the interaction with multiple factors. Furthermore, the two side surfaces seem to be functionally distinguishable, and this may determine the orientation of tracking PCNA along the DNA.
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PMID:Structure-function relationship of the eukaryotic DNA replication factor, proliferating cell nuclear antigen. 767 44

We have developed a novel immunoaffinity method for isolating a DNA polymerase alpha-associated DNA helicase from the yeast Saccharomyces cerevisiae. Earlier we have reported the characterization of a DNA helicase activity associated with the multiprotein DNA polymerase alpha complex from yeast [Biswas, E. E., Ewing, C. M., & Biswas, S. B. (1993) Biochemistry 32, 3030-3027]. We report here the isolation of the DNA helicase from the DNA polymerase alpha (pol alpha) complex bound to an anti-pol alpha immunoaffinity matrix. The DNA helicase activity eluted at approximately 0.35 M NaCl concentration. The eluted ATPase/helicase peak was further purified by size-exclusion high-performance liquid chromatography (HPLC). At low ionic strength (50 mM NaCl), it remained associated with other proteins and eluted as a large polypeptide complex. At high ionic strength (500 mM NaCl), the helicase dissociated, and the eluted ATPase/helicase fraction contained 90-, 60-, and 50-kDa polypeptides. Photoaffinity cross-linking of helicase with ATP during the isolation process demonstrated a 90-kDa polypeptide to be the likely ATP binding component of the helicase protein. The DNA helicase has single-stranded DNA (ssDNA)-stimulated ATPase and dATPase activities. The ATPase activity was stimulated by yeast replication protein A (RPA). The DNA helicase activity was stimulated by Escherichia coli ssDNA binding protein and RPA. The DNA helicase migrated on a DNA template in the 5'-->3' direction which is also the overall direction of migration of pol alpha on the lagging strand of the replication fork.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:DNA helicase associated with DNA polymerase alpha: isolation by a modified immunoaffinity chromatography. 825 76

We have analyzed the ATPase and dATPase activities associated with the yeast DNA polymerase alpha complex. The ATPase/dATPase was primarily a single-stranded DNA-dependent ATPase. Analysis of the stimulatory effect of a large number of DNA substrates demonstrated that polynucleotides longer than 60 nucleotides (nts) had the maximal effect. The stimulation by oligonucleotides smaller than 60 nts, in general, decreased proportionally with decreased length of the oligomer. Poly- or oligopyrimidines were twice as stimulatory as the poly- or oligopurines of the same length. In addition to DNA, replication protein A (RP-A), a single-stranded DNA (ssDNA) binding protein, also stimulated the ATPase activity. Photo-cross-linking of the ATP binding component of the pol alpha complex to [alpha-32P]ATP at 0 degree C resulted in the exclusive labeling of a 90-kDa polypeptide. The labeling was inhibited by ATP and dATP but not by any other ribo- or deoxynucleotides, which suggest that the 90-kDa polypeptide is specific for ATP/dATP binding and possibly the active site for the ATPase/dATPase. We have also reported here a novel DNA unwinding activity associated with the multiprotein complex of DNA polymerase alpha. The complex was able to unwind M13mp19 ssDNA hybridized to an oligonucleotide (17-60 nucleotides long) with a protruding 3'-terminus. Regardless of the size of the duplex, the DNA unwinding was significantly stimulated by RP-A, while RP-A itself did not have any DNA unwinding activity. Consequently, it appeared that the DNA polymerase alpha complex possessed a putative RP-A-dependent helicase activity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Characterization of the DNA-dependent ATPase and a DNA unwinding activity associated with the yeast DNA polymerase alpha complex. 838 85


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