Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The cellular localization of enzymes in Diplococcus pneumoniae was examined by fractionation of spheroplasts. A deoxyribonuclease implicated in the entry of deoxyribonucleic acid (DNA) into the cell during genetic transformation was located in the cell membrane. This enzyme, the major endonuclease of the cell (endonuclease I), which is necessary for the conversion of donor DNA to single strands inside the cell and oligonucleotides outside, thus could act at the cell surface. Another enzyme, the cell wall lysin (autolysin), was also found in the membrane fraction. Other enzymes, including amylomaltase, two exonucleases, and adenosine triphosphate-dependent deoxyribonuclease, and a restriction type endonuclease, were located in the cytosol within the cell. None of the enzymes examined were predominantly periplasmic in location. Spheroplasts were obtained spontaneously on incubation of pneumococcal cells in concentrated sugar solutions. The autolytic enzyme appears to be involved in this process. Cells that were physiologically competent to take up DNA formed osmotically sensitive spheroplasts two to three times faster than cells that were not in the competent state. Although some genetically incompetent mutants also formed spheroplasts more slowly, other such mutants formed them at the faster rate.
J Bacteriol 1975 Dec
PMID:Membrane location of a deoxyribonuclease implicated in the genetic transformation of Diplococcus pneumoniae. 0 Mar 66

All Bacillus subtilis R-type strains showing the phenomena of restriction and modification contain an endonuclease that inactivates in vitro the biological activity of a variety of DNAs lacking R-specific modification, such as transfecting SPPI, SPO2 and phi105 DNA, and transforming B. subtilis 168-type DNA. The corresponding DNAs carrying R-specific modification are resistant to the enzyme. The enzyme has been purified approximately 400-fold and is essentially free from contaminating double strand-directed unspecific exo- or endonuclease activity. Only Mg2+ is required as cofactor. The substrate DNAs are cleaved at specific sites. The double-stranded fragments produced from SPP1 DNA (molecular weight 2.5 x 10(7)) have an average molecular weight of about 3 x 10(5).
Mol Gen Genet 1975 Dec 30
PMID:Restriction and modification in B. subtilis. Purification and general properties of a restriction endonuclease from strain R. 0 56

Evidence has been found on an alkaline endonuclease activity in the cytoplasmic and nuclear fraction isolated from the thymus and spleen mice. The chromatin-associated endonuclease activity was identified only in the spleen. The enzyme(s) was active on both single- and double-stranded DNA, but the reaction was faster if single-stranded DNA was used as a substrate. Maximum activity was found in the pH range of 7.9 to 8.1 in the presence of 10 mM Mg2+ and 1 mM Ca2+. The enzyme(s) splits DNA, yielding 3'-hydroxyl terminated polynucleotides. It is suggested that this alkaline endonuclease(s) is responsible for the formation of deoxyribopolynucleotides in the thymus and spleen of irradiated mice.
Int J Radiat Biol Relat Stud Phys Chem Med 1977 Dec
PMID:Alkaline endonuclease(s) activity in the thymus and spleen of normal and irradiated mice. 2 4

Haemophilus influenzae Rf 232, showing the phenomena of restriction and modification, contains an endonuclease that inactivates in vitro the biological activity of DNAs lacking the strain-specific modification. This specific restriction endonuclease has been purified to near homogeneity by a procedure that includes DNA-agarose chromatography. This highly purified enzyme requires ATP and Mg2+ for activity and is stimulated by S-adenosylmethionine. The enzyme seems to cleave DNA at well-defined sites, since it produces a specific pattern of bands upon agarose gel electrophoresis. The enzyme has no ATPase activity. A methylase activity is observed in the course of the endonucleolytic reaction, which probably protects some of the DNA sites from cleavage.
Eur J Biochem 1978 Dec
PMID:Purification and properties of a new restriction endonuclease from Haemophilus influenzae Rf. 3 45

Using purified single-stranded ovalbumin complementary DNA (cDNAov) as a template for avian myeloblastosis (AM) virus reverse transcriptase, we have enzymatically synthesized a complete double-stranded cDNAov sequence. Our data suggests that many single-stranded cDNAov molecules contain short double-stranded sequences (hairpins) at their 3' termini capable of acting as primers for synthesis of complete double-stranded cDNAs. Optimum conditions for synthesis of the double-stranded cDNAov were found to be a high temperature (46 degrees) and a low salt concentration. Nevertheless, in all cases 40% of the initial single-stranded cDNAov molecules fail to prime for synthesis of a complementary double strand. Following synthesis, the second DNA strand is covalently linked to the first cDNAov strand as shown by analysis on alkaline sucrose gradients. The two strands have a high Tm on hydroxylapatite (89 degrees). These intact double-stranded cDNAov structures have a bouyant density in CsCl gradients of 1.700 g/cm3 and rapidly renature after heat denaturation with a C0t1/2 value of less than 2 X 10(-6) mol s liter(-1). All size classes of cDNAs, i.e. partial as well as complete transcripts of the mRNA, are capable of forming double-stranded structures. The closed loop of the double-stranded cDNAov could be opened with S1 nuclease. The denatured complementary strands of the cDNAov then renatured with the appropriate second order kinetics at a C0t1/2 value of 1.89 X 10(-3) mol s liter(-1). Using the enzyme terminal deoxyribonucleotidyltransferase to label to free 3'-terminal end of double-stranded [32P]cDNAov with 3H, we demonstrate a convenient procedure to study the site for restriction endonuclease cleavage within the ovalbumin gene.
J Biol Chem 1976 Dec 10
PMID:The ovalbumin gene. In vitro enzymatic synthesis and characterization. 6 59

Full-length, complementary DNAs were prepared to rainbow trout protamine mRNA using reverse transcriptase and were labelled during synthesis by the replacement of dATP by [alpha32P]dATP or dTTP by [alpha32P]dTTP. The 32P-labelled protamine complementary DNAs were digested with T4 endonuclease IV. Fragments from the digests were separated in two dimensions, and those discrete fragments which could be identified from both the A-labelled and T-labelled complementary DNAs were subjected to sequence analysis. The sequences described here all arise from the non-coding region. One pentadecanucleotide contained the sequence A-A-U-A-A-A which has been reported by Proudfoot and Brownlee ((1976) Nature 263, 211-214) to occur in the noncoding regions of six other eukaryotic mRNAs.
Biochim Biophys Acta 1977 Dec 14
PMID:Protamine messenger RNA from rainbow trout testis contains the nucleotide sequence A-A-U-A-A-A in an untranslated region. 7 66

We have determined a 139-base-pair sequence of adenovirus 2 DNA that is located immediately leftwards of the cleavage site for endonuclease Sma I at position 51.1. The established sequence includes the hexon AUG initiator codon, located 75--77 nucleotides leftwards of this cleavage site, and codons for the first 26 amino acids of the hexon polypeptide. By the use of purified hexon mRNA as a template and separated strands of small restriction enzyme fragments as specific primers, the complete 5' noncoding region of the hexon mRNA was synthesized and part of its sequence was determined. The tripartite leader sequence of the hexon mRNA starts 39 nucleotides upstream from the initiator AUG triplet and the total length of the 5' noncoding part of the hexon mRNA was estimated to be 235 nucleotides. The sequence at the junction of the leader sequence permits the formation of secondary structures that may be of importance for the splicing reaction.
Proc Natl Acad Sci U S A 1978 Dec
PMID:Nucleotide sequence at the junction between the coding region of the adenovirus 2 hexon messenger RNA and its leader sequence. 8 49

Conditions are described which give an efficient synthesis of DNA copies of cowpea mosaic virus (CPMV) RNAs, using avian myeloblastosis reverse transcriptase and oligo (dT) primers. Maximum incorporation of dAMP into cDNA is attained with 0.4 to 0.8 mM of each deoxynucleoside triphosphate, 12 mM Mg++ and 60 mM K+ ion concentrations. High enzyme concentrations (up to 100 units/ml) were used. Under these conditions over 1000 pmoles of dAMP were incorporated per reaction. The cDNA:RNA molar ratio approached 0.3 when 1 pmole CPMV RNA was used as template. The products were heterogeneous but large. Bottom component RNA (about 6000 nucleotides long) was copied into cDNA molecules ranging from about 1000 to 4000 nucleotides, and middle component RNA (about 4000 nucleotides long) was copied into cDNA mostly between 500 and 2000 nucleotides long, on average about 1500, which can be cleaved by restriction endonuclease Hae III into two fragments of 880 and 540 nucleotides.
Nucleic Acids Res 1978 Dec
PMID:Efficient reverse transcription of cowpea mosaic virus RNAs. 8 93

The DNA polymerase induced by Bacillus subtilis bacteriophage PBS2 has a Stokes radius of 7.2 in buffers of high ioninc strength, suggesting a molecular weight in the range 145,000 to 195,000. The polypeptide bands observed on gel electrophoresis in dodecyl sulfate have apparent molecular weights of 78,000 and 69,000 (and possibly another 27,000) in equimolar amounts. In buffers of low ionic strength, the enzyme appears to form large aggregates and even precipitates, with about 90% loss of activity. A nuclease activity co-purifies with the PBS2 DNA polymerase and shows similar responses to changes in pH, MgCl2, N-ethylmaleimide, temperature, and dextran sulfate levels. The nuclease produces deoxyribonucleoside 5'monophosphates from denatured DNA containing thymine or uracil. No endonuclease activity is detectable on supercoiled DNA. The inhibition of nuclease activity by added deoxyribonucleoside triphosphates, the DNA-dependent turnover of triphosphates, to free monophosphates during DNA polymerization, the inhibition of nuclease activity by 3'-phosphates on the DNA template-primer, and the pattern of digestion of 5'-[32P]phosphate-labeled DNA all indicate that the PBS2 DNA polymerase-associated hydrolytic activity is a 3' leads to 5'-exonuclease.
J Biol Chem 1978 Dec 10
PMID:Characterization of the Bacillus subtilis bacteriophage PBS2-induced DNA polymerase and its associated exonuclease activity. 10 39

An endonuclease which hydrolyzes depurinated DNA has been purified from extracts of Bacillus subtilis cells. The endonuclease is a monomeric protein and has a molecular weight of around 56,000. The enzyme is specific for apurinic sites in double-stranded DNA, has a pH optimum at 8.0, and is slightly stimulated with 50 mM NaCl but completely inhibited with 500 mM NaCl. It requires no divalent cations and is insensitive to EDTA; it has no associated exonuclease. These properties are very similar to those of Escherichia coli endonuclease IV, which is also insensitive to EDTA and has no exonuclease activity, and very different from those of the main endonuclease for apurinic sites (endonuclease IV) of the same bacterium.
J Biol Chem 1978 Dec 10
PMID:Purification and properties of a Bacillus subtilis endonuclease specific for apurinic sites in DNA. 10 48


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