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:3.1.30.2 (endonuclease)
18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Endonucleases from Micrococcus luteus that induce single-strand breaks in gamma-irradiated DNA have been separated chromatographycally into two groups. The first group involves two different enzymes: AP-endonuclease II (mol. weight 30 000) and AP, UV-endonuclease I (mol. weight 15 000) that recognize alkali-labile lesions in gamma-irradiated DNA and apurinic sites in DNA heated at 70 degrees C, pH 6.08 AP-endonuclease II in cooperation with DNA polymerase from M. luteus and T4 phage-induced polynucleotide ligase is capable of carrying out in vitro complete excision repair of alkali-labile lesins in gamma-irradiated DNA. The second group involves gamma-endonucleases X and Y that act on alkalistable gamma-ray lesions. gamma-endonucleases X and Y can be separated by chromatography on DEAE-cellulose but possess similar properties. Activity of gamma-endonucleases toward gamma-irradiated DNA is inhibited by only heavily UV-irradiated DNA (15 000 ergs/mm2). The data are consistent with the hypothesis that gamma-endonucleases are specific for thymine glycols (t' and tUV) in UV- and gamma-irradiated DNA.
...
PMID:[Analysis of the activity of Micrococcus luteus endonucleases with respect to gamma-irradiated DNA]. 2 Jan 61

DNA from a temperate phage rho 11 and chromosomal DNA of Bacillus subtilis 168 were digested with endonuclease EcoRI and then ligated with T4 polynucleotide ligase. The ligated DNA fragments were used to transform a lysogenic strain, B. subtilis spoA12 lys21 hisA1 leuA8 p11, and Lys+, His+ or Leu+ transformants were selected. The cells of each type were then mixed, grown and treated with mitomycin C; the induced phages were tested for abilities abilities to form plaques and to tranduce the auxotrophic marker. Various types of plaque-forming or defective phages which transduce hisA or lys marker at considerably high frequencies were thus obtained.
...
PMID:A method for construction of specialized transducing phage rho 11 of Bacillus subtilis. 10 55

DNA molecules cut with endonuclease R Eco Ri can be joined at Eco Ri cleavage sites by incubation with polynucleotide ligase. In order to define the optimum conditions for this reaction, linear Simian Virus 40 DNA molecules (SV40(Lri)) produced by endonuclease R Eco Ri cleavage of SV40 form i DNA were joined using polynucleotide ligases specified by bacteriophage T4 and Escherichia coli. We have determined that the concentration of the substrate DNA molecules is the most important factor determining the distribution of covalently joined product molecules into a variety of circular and linear monomeric and oligomeric species.
...
PMID:Joining of simian virus 40 DNA molecules at endonuclease R Eco Ri sites by polynucleotide ligase and analysis of the products by agarose gel electrophoresis. 18 Oct 70

An endonuclease activity has been purified approximately 800-fold from nuclei of 3T3 cells infected with polyoma virus. The purfied enzyme catalyzes an endonucleoytic cleavage of single- and double-stranded DNA and single-stranded RNA. Evidence that the activity towards these substrates resides in the same protein molecule is provided by the finding that they co-sediment in sucrose gradients and have identical rates of heat inactivation. Studies on the DNase activity shows that the rate of hydrolysis of single-stranded T7 DNA is 100-fold greater than that for double-stranded T7 DNA. Single-stranded DNA is extensively hydrolyzed to low molecular weight acid-insoluble products. With duplex DNA as substrate, only a limited number of single strand breaks are introduced. A limit digest with polyoma DNA (component I) as substrate results in the introduction of four breaks per strand. The phosphdiester bond interruptions can be repaired by polynucleotide ligase. Approximately 80% of the 5' termini present at the point of phosphodiester bond cleavage are purine nucleotides. Additional studies have demonstrated that a similar endonuclease is present in nuclei of uninfected cells and that this enzyme purified 400-fold has catalytic properties identical with those of the endonuclease from infected cells.
...
PMID:Purification and properties of an endonuclease from nuclei of uninfected and polyoma-infected 3T3 cells. 18 96

Fouteen "flush"-ended segments originate from the action of the restriction endonuclease Hae III of Haemophilus aegiptius on the DNA of the colicinogenic factor ColE 1 (A. Oka and M. Takanami, Nature, 264, 191, 1976). They are joined by the T4 polynucleotide ligase. The reaction can be monitored by gel electrophoresis, electron microscopy and resistance to phosphatase of the 5'-32P labelled ends. The joined products are a random recombination of the original segments, and can be cleaved by the same Hae III endonuclease to restore the exact electrophoretic pattern of the Hae III-cut ColE 1 DNA. In a properly diluted mixture of 5'-32P segments treated with T4 ligase, the level of phosphatase resistance is very close to the frequency of circle-formation as determined by electron microscopy: thus, the joining of the "flush"-ends involves the formation of circular structures covalently closed in both strands.
...
PMID:Restoration by T4 ligase of DNA sequences sensitive to "flush" cleaving restriction enzyme. 19 43

Bacillus circulans NRRL B-3312, a nonpathogenic bacterium that produces the aminoglycoside antibiotic butirosin, is known to contain an aminoglycoside phosphotransferase that is similar to the neomycin phosphotransferases of clinically isolated antibiotic-resistant bacteria. Purified DNAs from B. circulans and the plasmid ColE1-ApR were digested with EcoRI endonuclease and the resulting fragments covalently joined with polynucleotide ligase. The recombined DNA was used to transform E. coli and ampicillin-neomycin resistant colonies were selected. Analysis of several clones indicated that neomycin resistance in the E. coli transformants was due to the presence of the B. circulans phosphotransferase gene. This observation is consistent with the notion that anitbiotic-modifying enzymes from antibiotic-producing organisms may be the sources of antibiotic resistance in plasmid-containing bacteria.
...
PMID:Aminoglycoside-modifying enzyme of an antibiotic-producing bacterium acts as a determinant of antibiotic resistance in Escherichia coli. 32 54

Py pyrimidine dimers Py correndonucleases I and II from Micrococcus luteus act exclusively on thymine-thymine, cytosine-cytosine, and thymine-cytosine cyclobutyl dimers in DNA, catalyzing incision 5' to the damage and generating 3'-hydroxyl and 5'-phosphoryl termini. Both enzymes initiate excision of pyrimidine dimers in vitro by correxonucleases and DNA polymerase I. The respective incised DNAs, however, differ in their ability to act as substrate for phage T4 polynucleotide ligase or bacterial alkaline phosphatase, suggesting that each endonuclease is specific for a conformationally unique site. The possibility that their respective action generates termini which represent different degrees of single strandedness is suggested by the unequal protection by Escherichia coli binding protein from the hydrolytic action of exonuclease VII.
...
PMID:Micrococcus luteus correndonucleases. II. Mechanism of action of two endonucleases specific for DNA containing pyrimidine dimers. 33 May 26

Double-stranded DNA segments with completely base-paired ends were obtained by the action of various restriction endonucleases on phage and plasmid DNAs. These segments were joined covalently by the T4 polynucleotide ligase. The joining was monitored by the electron microscopy count of intramolecularly circularized segments. The highest extent of joining, close to 75%, was observed at 15-25 degrees C with the segments resulting from the action of the Bacillus subtilis (strain R) restriction endonuclease Bsu on the DNA of bacteriophage SPPI or of the plasmid pSC 101. The joining of double-stranded termini required about 10 times more enzyme than the short single-stranded termini produced by the Escherichia coli restriction endonuclease EcoRI. A shortened purification of the T4 ligase was found to give an enzyme devoid of interfacing nucleases.
...
PMID:Use of the T4 polynucleotide ligase in the joining of flush-ended DNA segments generated by restriction endonucleases. 35 May 85

The method developed for the total synthesis of a given DNA containing biologically specific sequences consists of the following. The DNA in the double-stranded form is carefully divided into short single-stranded segments with suitable overlaps in the complementary strands. All the segments are chemically synthesized starting with protected nucleosides and mononucleotides. The 5'-OH ends of the appropriate oligonucleotides are then phosphorylated with the use of [y-32P]ATP and polynucleotide kinase. A few to several neighboring oligonucleotides are then allowed to form bihelical complexes in aqueous solution, and the latter are joined end to end by polynucleotide ligase to form covalently linked duplexes. Subsequent heat-to-tail joining of the short duplexes leads to the total DNA. The methods are described for the construction of a biologically functional suppressor transfer RNA gene. The total work involved (i) the synthesis of a 126-nucleotide-long bihelical DNA corresponding to a known precursor to the tyrosine suppressor transfer RNA, (ii) the sequencing of the promoter region and the distal region adjoining the C-C-A end, which contained a signal for the processing of the RNA transcript, (iii) total synthesis of the 207 base-pair-long DNA, which included the control elements, as well as the Eco R1 restriction endonuclease specific sequences at the two ends, and (iv) full characterization by transcription in vitro and amber suppressor activity in vivo of the synthetic gene.
...
PMID:Total synthesis of a gene. 36 49

ColE1amp plasmids carrying the entire bio gene cluster were constructed in vitro using ColE1amp as the cloning vehicle and a lambda transducing phage, lambdaatt2, as the source of bio DNA. Restriction endonuclease EcoRI digests of ColE1amp and lambdaatt2 DNA were joined by polynucleotide ligase and plasmids bearing the entire bio gene cluster were selected, after transformation, in bio deletion strains of E. coli. Recombinant DNA molecules contained one ColE1amp fragment (7.4 X 10(6) daltons) and one lambdaatt2 DNA fragment (5.4 X 10(6) daltons). Clones carrying ColE1 amp-bio plasmids produce elevated levels of biotin and biotin synthetase activity.
...
PMID:Isolation and characterization of a ColE1 plasmid containing the entire bio gene cluster of Escherichia coli K12. 36 79


1 2 3 Next >>

---