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

A new temperate bacteriophage, rho11, isolated by J. Hoch, has been characterized. This new phage is very similar to the temperate phage phi3T in size (380 nm), host range, homoimmunity, DNA buoyant density (1.694 g/ml), antigenicity, and molecular weight (around 6.0 X 10(7)) as determined in gels. Like phi3T, rho11 converts thymine auxotrophs to prototrophy at high frequency (250 out of 250 tested). Phage rho11 differs from phi3T in plaque morphology and in the endonuclease R-EcoRI digest pattern. Sixteen of the 20 rho11 DNA fragments have migration patterns corresponding to those of the 21 fragments of phi3T. The close similarities yet clear differences between these phages suggest that the two phages have a common ancestor.
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PMID:New temperate bacteriophage for Bacillus subtilis, rho 11. 6 60

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.
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PMID:The ovalbumin gene. In vitro enzymatic synthesis and characterization. 6 59

A restriction endonuclease has been partially purified from Haemophilus influenzae Rf232 containing the genetically determined system of restriction and modification of DNA. The enzyme requires ATP for the degradation of transfecting phage DNA.
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PMID:Host specificity of DNA in Haemophilus influenzae: DNA restriction enzyme from H. influenzae Rf232. 6 3

Sequences of human beta-globin mRNA were determined by analysis of complementary DNA. beta-mRNA was transcribed into double-stranded cDNA by RNA-dependent DNA polymerase. cDNA was cut by restriction endonucleases and the fragments were terminally labeled by means of polynucleotide kinase and [gamma-32P]ATP. After purification, fragments were degraded by snake venom phosphodiesterase. Alternatively single-stranded [32P]cDNA was prepared by transcription in the presence of [alpha-32P]dCTP and actinomycin D; the product was digested by endonuclease IV and degraded by snake venom phosphodiesterase. cDNA tracts obtained by both labeling methods enabled us to construct a sequence for the translated and 3'-terminal untranslated regions of human beta-mRNA.
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PMID:Human beta-globin messenger RNA. III. Nucleotide sequences derived from complementary DNA. 6 58

The circular DNA of hepatitis B Dane particles, which serves as the primer/template for an endogenous DNA polymerase, was analyzed by electrophoresis before and after a polymerase reaction and after digestion by restriction endonuclease or single-strand-specific endonuclease S1. The unreacted molecules extracted from the particles were electrophoretically heterogeneous, and treatment with S1 nuclease produced double-stranded linear DNA ranging in length from 1,700 to 2,800 base pairs (bp). After an endogenous DNA polymerase reaction, two discrete species of DNA molecules were found: a circular form and a linear form 3,200 bp long. The reaction resulted in a population of molecules with an elongated and more homogeneous double-stranded region. These results suggest that the circular molecules in Dane particles have single-stranded regions of varying lengths that are made double stranded during the DNA polymerase reaction. The endogenous DNA polymerase was found to initiate apparently at random in a region spanning more than a third of the molecule. Analysis of restriction endonuclease cleavage fragments of the fully elongated DNA revealed that although the molecules were of a uniform length, they were somewhat heterogeneous in sequence. The sum of the sizes of the 10 major endonuclease Hae III-generated fragments, detected by ethidium bromide, was 3,880 bp. Two additional fragments (B and G) detected by autoradiography after an endogenous DNA polymerase reaction with (32)P-labeled deoxynucleoside triphosphates made the total 4,910 bp.
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PMID:Structure of hepatitis B Dane particle DNA and nature of the endogenous DNA polymerase reaction. 6 27

Brief exposure of covalently closed circular duplex PM2 DNA to low concentrations of the clinical bleomycin mixture (Blenoxane) resulted in specific fragmentation of the genome that does not depend on the presence of superhelical turns. The double-strand breaks are in fact produced at several discrete sites on the PM2 genome but frequently occurring near the HpaII restriction endonuclease cleavage site. Initial rates of formation of nicked circular and linear duplex PM2 DNAs are reduced to different extents as the ionic strength of the reaction is increased. Increasing ionic strength is most effective in reducing the initial rate and overall yield of apparent double-strand scissions compared with single-strand scissions in the bleomycin-treated PM2 DNA.
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PMID:Bleomycin-specific fragmentation of double-stranded DNA. 7 75

The antigenic relationship between the two murine papovaviruses, K virus and polyoma virus, was examined by serological techniques to determine whether they shared any antigenic components. No cross-reactivity was found associated with the viral (V) antigens by the indirect immunofluorescence, neutralization, or hemagglutination-inhibition tests. The tumor (T) antigens expressed in transformed cells or cells productively infected by either K or polyoma virus did not cross-react by indirect immunofluorescence. An antigenic relationship was detected, however, among the late proteins of K virus, polyoma virus, simian virus 40, and the human papovavirus BKV, when tested with either hyperimmune sera prepared against polyoma virus and simian virus 40 or sera prepared against disrupted virions. The nucleic acids of K and polyoma viruses were compared by agarose gel electrophoresis and restriction endonuclease analysis. No nucleotide sequence homology between the genomes of these two viruses was detectable by DNA-DNA hybridization techniques under stringent conditions. The genome of K virus was found to be slightly smaller than that of polyoma virus, and the cleavage patterns of the viral DNAs with six restriction endonucleases were different. These findings indicate that there is little relationship between these two murine papovaviruses.
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PMID:Characterization of K virus and its comparison with polyoma virus. 8 18

We have determined the recognition sequence of the restriction endonuclease KpnI, previously isolated from Klebsiella pneumoniae. The enzyme cleaves the twofold rotationally symmetric sequence (see book for formula) at the positions indicated by the arrows, producing 3' protruding cohesive ends, four nucleotides in length. The specific cleavage site was unambiguously deduced using both 3' and 5' end analyses of KpnI generated restriction fragments of simian-virus 40 (SV40) DNA (1 site), adenovirus-2 (Ad-2) DNA (8 sites), and a plasmid (pCRI) DNA (2 sites).
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PMID:Recognition sequence of restriction endonuclease KpnI from Klebsiella pneumoniae. 8 35

Chinese hamster ovary cells (CHO) were X-irradiated in G2 stage of the cell cycle and immediately treated, in the presence of inactivated Sendai virus, with Neurospora endonuclease (E.C. 3.1.4.), an enzyme which is specific for cleaving single-stranded DNA. With this treatment, the frequencies of all types of chromosome aberrations increased when compared to X-irradiated controls. These results are interpreted as due to the conversion of some of the X-ray induced single-stranded DNA breaks into double-strand breaks by this enzyme. Similar enhancement due to this enzyme was found following treatment with methyl methanesulfonate (MMS) and bleomycin, but not following UV and mitomycin C. Addition of Micrococcus endonuclease and Neurospora endonuclease to the cells did not alter the frequencies of aberrations induced by UV. The introduction of enzymes with specific DNA-repair function offers possibilities to probe into the molecular events involved in the formation of structural chromosome aberrations induced by different classes of physical and chemical mutagens.
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PMID:Molecular mechanisms involved in the production of chromosomal aberrations. I. Utilization of Neurospora endonuclease for the study of aberration production in G2 stage of the cell cycle. 8 35

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.
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PMID:Nucleotide sequence at the junction between the coding region of the adenovirus 2 hexon messenger RNA and its leader sequence. 8 49


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