共查询到20条相似文献,搜索用时 46 毫秒
1.
G F Gerard C Gurgo D P Grandgenett M Green 《Biochemical and biophysical research communications》1973,53(1):194-201
Rifampicin and three rifamycin SV derivatives with different lipophilic side chains were tested as inhibitors of a number of purified enzymes including the α and αβ forms of RNA-directed DNA polymerase of avian myeloblastosis virus (AMV). (2,5-dimethyl-4-N-benzyl demethyl rifampicin), (O-n-octyloxime of 3-formyl rifamycin SV) and C-27 (rifamycin SV with a dicyclohexylalkyl substituted piperidyl ring at the 3-position) at concentrations less than 20 to 40 μg/ml completely inhibited the RNA- and DNA-directed DNA polymerase and RNase H activities of both AMV enzymes. Rifampicin was inactive at 100 μg/ml. When used against a variety of non-polymerizing enzymes such as alkaline phosphatase, glutamate-oxaloacetate transaminase, DNase I, and RNase A, these derivatives were inactive at drug concentrations between 100 and 200 μg/ml. Polynucleotide phosphorylase was inhibited slightly by all three derivatives. These results support the idea that rifamycin SV derivatives with appropriate 3-substituted side-chains are specific inhibitors of nucleic acid polymerizing enzymes. 相似文献
2.
George Boguslawski William S. Oetting Dean A. Stetler 《Biochemical and biophysical research communications》1977,78(2):684-689
An enzyme, ribonucleotide polymerase, isolated from the yeast phase of a fungus, has been found to stimulate the incorporation of dTMP in the reaction catalysed by DNA polymerase from and . The stimulation is dependent on the amount of ribonucleotide polymerase added. The data indicate that protein-protein interaction is responsible for the increase in DNA synthesis. It is suggested that ribonucleotide polymerase may be involved in supplying short RNA primers for DNA polymerase. 相似文献
3.
DNA polymerase activities in cell-free lysates of unfertilized eggs, larvae and immature ovaries of were compared to purified DNA polymerase I using several natural and synthetic templates. The templates were tested as the native and denatured forms of normal and DNase I treated molecules. Although the polymerases tended to prefer DNase I treated Xenopus DNA over the other templates tested, so did the polymerase I. In general, the template preferences of the polymerases studied depended in complex ways on both the form and the species of origin of the template. 相似文献
4.
Stuart L. Marcus Gregg Lipschik Generosa Trueba Cyrus J. Bacchi 《Biochemical and biophysical research communications》1980,93(4):1027-1035
A single peak of DNA polymerase activity from extracts of , obtained by DEAE-cellulose and phosphocellulose ion-exchange chromatography, was resolved into two peaks differing in KCl concentration necessary to elute them from a DNA-agarose column. Peak I (eluting at 0.2 M KCl) and Peak II (eluting at 0.4 M KCl), differed in response to increasing KCl concentrations, although both functioned optimally with Mg2+ as divalent cation when DNA synthesis was directed either by activated DNA or poly (dC)·(dG)12–18. Due to the potential significance of polyamines in the metabolism of , the effect of exogenous polyamine on rates of DNA synthesis by the peak I and II enzymes was compared with that of murine DNA polymerase alpha. Only the peak I enzyme was significantly stimulated (up to 4-fold) by the biologically active polyamines spermine and spermidine at physiological concentrations. The response of the peak I enzyme resembled that of the alpha polymerase. This result suggests a possible functional difference between peak I and II enzymes, as well as a potential target site for trypanocidal drug development. 相似文献
5.
Neomycin inhibits DNA dependent DNA and RNA synthesis catalyzed by DNA polymerase I and RNA polymerase from . The effect of the antibiotic is more pronounced towards DNA synthesis. The inhibition of DNA synthesis is competitive with template DNA, does not reverse with excess deoxynucleoside triphosphate, Mg2+ or enzyme DNA polymerase I. Neomycin does not reduce the number of potential 3′ -OH end or primer. It seems to shorten the size of the newly formed polynucleotide. 相似文献
6.
V D'Aurora A M Stern D S Sigman 《Biochemical and biophysical research communications》1978,80(4):1025-1032
The inhibition by 1,10-phenanthroline of DNA polymerase I has recently been attributed to the formation in the assay mixtures of a unique and effective inhibitor, the 2:1 1,10-phenanthroline-cuprous ion complex (1). We have now found that this coordination complex is also an effective inhibitor of DNA dependent RNA polymerase, Micrococcus luteus DNA dependent DNA polymerase, and T-4 DNA dependent DNA polymerase. This conclusion is based either on the requirement of a thiol for 1,10-phenanthroline inhibition or on the reversal of 1,10-phenanthroline inhibition by the non-inhibitory cuprous ion specific chelating agent 2,9-dimethyl-1,10-phenanthroline. 2,2′,2″-Terpyridine is also very effective at relieving 1,10-phenanthroline inhibition. The reversal of 1,10-phenanthroline inhibition should be attempted before it is claimed that 1,10-phenanthroline inhibits any polymerases by coordinating a zinc ion at the active site. 相似文献
7.
Excision of thymine dimers by proteolytic and amber fragments of E. coli DNA polymerase I 总被引:11,自引:0,他引:11
Excision of thymine dimers from specifically incised ultraviolet irradiated DNA by DNA polymerase I is stimulated by concurrent DNA synthesis. The 36,000 molecular-weight “small fragment” obtained by limited proteolysis of DNA polymerase I, which retains only the 5′ → 3′ exonuclease activity, also excises thymine dimers, but at one-tenth the rate of the intact enzyme. However, the rate of excision is increased by addition of the “large” 76,000-molecular weight fragment. With the further addition of the 4 deoxynucleoside triphosphates, permitting DNA synthesis to occur, excision approaches rates observed with the intact enzyme. The same result was obtained with a fragment of DNA polymerase I with 5′ → 3′ exonuclease activity that is present uniquely in polymerase I mutants. 相似文献
8.
Extracts of Aexl which contains a temperature sensitive 5′→3′ exonuclease function of polymerase I accomplish the selective excision of products of the 5,6-dihydroxy-dihydrothymine type from γ-irradiated DNA and OsO4-oxidized polyd(A-T) at the permissive temperature (30°) but not at the nonpermissive temperature (42°). The 5′→3′ exonuclease activity of polymerase I, therefore, acts as a repair exonuclease in γ-ray excision repair. 相似文献
9.
Are all nucleotidyl transferases metalloenzymes? 总被引:5,自引:0,他引:5
P Valenzuela R W Morris A Faras W Levinson W J Rutter 《Biochemical and biophysical research communications》1973,53(3):1036-1041
10.
11.
The effect of ionising radiation and chemical methylation upon the activity and accuracy of E. COLI DNA polymerase I 总被引:1,自引:0,他引:1
R Saffhill 《Biochemical and biophysical research communications》1974,61(2):802-808
The activity of DNA polymerase I decreases on treatment with γ-rays, methylnitrosourea or dimethyl sulphate. In the case of the first two agents the decrease in activity is accompanied by a decrease in the accuracy of the enzyme in an assay. There is no detectable change in the ratio of DNA polymerase activity to 3′→5′ exonuclease activity on treatment. 相似文献
12.
Mutational alteration of Bacillus subtilis DNA polymerase 3 to hydroxyphenylazopyrimidine resistance: polymerase 3 is necessary for DNA replication 总被引:18,自引:0,他引:18
A spontaneous mutant of resistant to killing by two hydroxyphenylazopyrimidines has been isolated. The DNA polymerase III of this mutant is resistant to inhibition by these drugs. The Ki for 6-(p-hydroxyphenylazo)-uracil (HPUra) is 20 μM, about 40 times higher than the Ki of the wild-type enzyme. The mutant and wild-type polymerases behave similarly during purification, are sensitive to N-ethylmaleimide and to 0.1 M KCl, and have the same Km for dGTP (0.5 μM). The HPUra inhibition of both enzymes is attenuated competitively by dGTP. We conclude that polymerase III is the target for hydroxyphenylazopyrimidines , and since the drugs specifically inhibit replicative DNA synthesis, polymerase III is necessary for DNA replication. 相似文献
13.
Ultraviolet light-induced recombination 总被引:2,自引:0,他引:2
R B Helling 《Biochemical and biophysical research communications》1973,55(3):752-757
Stimulation of transduction in by ultraviolet irradiation of the transducing phage P1 requires the nuclease but not the product or DNA polymerase I. It is hypothesized that the first step in “normal” recombination can be bypassed by any procedure generating single-stranded ends of DNA (as, for example, by nuclease activity). 相似文献
14.
Franz Meußdoerffer 《Biochemical and biophysical research communications》1980,97(2):423-429
The occurrence of the proteinase A inhibitors 2 and 3 was investigated in wild type strains of and as well as in several strains of commercial baker's yeast. Haploid and diploid strains of contain only proteinase A inhibitor 3 whereas in only proteinase A inhibitor 2 is found. Strains of commercial baker's yeast contain either proteinase A inhibitor 3 or both inhibitors in a constant ratio of 1:3. Single cell cultures isolated from a strain of commercial baker's yeast also contain a mixture of the two inhibitors. Therefore, baker's yeast is not a mixture of two different cell types but the genome for both inhibitors is present in each single cell. In general, the results indicate that the occurrence of the two proteinase A inhibitors is determined genetically and, therefore, they may be called “isoinhibitors”. 相似文献
15.
Jerard Hurwitz Sue Wickner Michel Wright 《Biochemical and biophysical research communications》1973,51(2):257-267
Purified RNA polymerase, DNA polymerase III and unwinding protein of catalyze limited rifampicin sensitive fd or ØX 174 DNA-dependent DNA synthesis. A protein has been partially purified from which stimulates rifampicin sensitive dXMP incorporation in this system 20 to 30 fold. This protein also stimulates DNA synthesis catalyzed by DNA polymerases I and II; the stimulation occurs in reactions primed with natural and synthetic DNAs as well as RNA-DNA hybrids. The protein is not a product of the known dna genes. In contrast to the above system of purified enzymes, rifampicin sensitive dXMP incorporation in crude extracts of is specifically dependent on fd but not ØX 174 DNA. An additional factor has been isolated from extracts of which restores specificity to the purified rifampicin sensitive system by preventing ØX 174 DNA from serving as a template. 相似文献
16.
Possible involvement of DNA polymerases alpha and beta in bleomycin-induced unscheduled DNA synthesis in permeable HeLa cells 总被引:1,自引:0,他引:1
S Seki M Ohashi H Ogura T Oda 《Biochemical and biophysical research communications》1982,104(4):1502-1508
DNA polymerases involved in bleomycin-induced unscheduled DNA synthesis in some permeable human cells and rodent cells were studied by using selective inhibitors (aphidicolin, 2′,3′-dideoxythymidine-5′-triphosphate and N-ethylmaleimide) for DNA polymerases. The results suggest that both DNA polymerases α and β are involved in bleomycin-induced unscheduled DNA synthesis in permeable HeLa-S3 cells and probably in some other permeable human cells (HEp-2, KB and WI-38 VA-13 cells). Bleomycin-induced unscheduled DNA synthesis in some permeable rodent cells (, 3T3, 3Y1 and XC cells) is mostly attributed to DNA polymerase β. 相似文献
17.
α factor is a diffusible substance produced by cells of the mating type which inhibits cell division (1) and the initiation of nuclear DNA synthesis (2) in cells of the mating type. In this report, it is shown that mitochondrial DNA synthesis continues at a normal rate in cells for at least 6 hours in the presence of α factor, resulting in a 5-fold increase in the amount of mitochondrial DNA per cell. The continued synthesis of mitochondrial DNA in the absence of nuclear DNA synthesis allows specific labeling of yeast mitochondrial DNA. 相似文献
18.
Conditions for the production of a complementary DNA sequence for use in studies of ribosomal RNA are described. . DNA polymerase I is used to transcribe highly purified 28S ribosomal RNA from rat liver. The reaction is sensitive to the tertiary structure of the rRNA template-primer. The complementary DNA hybridizes to its rRNA template with a of 0.02. The hybrid formed between 28S ribosomal RNA and complementary DNA has a Tm of 73°C. The probe reacts with total rat nuclear RNA with a of 1.0. 相似文献
19.
The effect of depurination of polynucleotide templates on the fidelity of DNA synthesis in vitro has been determined. The fidelity of DNA synthesis with Escherichia coli DNA polymerase I, avian myeloblastosis virus DNA polymerase and human placenta DNA polymerase-β is decreased as a result of depurination of the poly[d(A-T)], poly[d(G-C)]and poly[d(A)]templates. The error rate with poly[d(A-T)]increased from to using E. coli Pol I, and from to using the myeloblastosis virus DNA polymerase. Depurination of poly[d(A)]increased the error rate from to using E. coli Pol I, and from to using the DNA polymerase-β from human placenta. Depurination of poly[d(G-C)]resulted in an increase in the error rate with E. coli Pol I from to , and with the virus DNA polymerase from to . This misincorporation is shown to be directly proportional to the extent of depurination. Deletion experiments and alkaline sucrose gradient analyses suggest that the incorporation of complementary and non-complementary nucleotides is dependent on polymerization, and occurs in the same newly synthesized product. Kinetic studies and nearest-neighbor analyses indicate that the incorporation of non-complementary nucleotides occurs randomly as single-base substitutions. The nearest-neighbor studies also suggest that any of the four deoxynucleotides can be incorporated opposite apurinic sites. The number of each nucleotide incorporated relative to the number of apurinic sites was determined to be for dGTP, for dCTP, for dATP and for dTTP with both the poly[d(A-T)] and poly[d(A)] templates. The frequencies of misincorporation relative to the number of apurinic sites with the poly[d(G-C)]template were for dATP, for dTTP, for dGTP and for dCTP. Hydrolysis at the apurinic sites by alkali treatment reversed the effects of depurination on fidelity. The error rates with the depurinated templates were reduced to within 2% of those obtained prior to depurination, providing additional evidence that the misincorporation after depurination results from apurinic sites on the template. These results suggest a possible relationship between depurination of DNA and errors in DNA replication and/or repair. 相似文献