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)

Spheroplasts are insensitive to colicin E(2) and do not show deoxyribonucleic acid (DNA) degradation even in the presence of massive amounts of E(2). However, when both endonuclease I and E(2) were present, spheroplast DNA was degraded by an endonucleolytic activity which gave rise primarily to double-strand DNA cleavages, producing fragments having an average molecular weight of 9 x 10(6). Pancreatic ribonuclease could substitute for colicin E(2) in the reconstitution system, but pancreatic deoxyribonuclease could not replace endonuclease I. However, colicin E(2) could not activate transfer ribonucleic acid-inhibited endonuclease I in an in vitro system where pancreatic ribonuclease caused full stimulation.
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PMID:Reconstitution of colicin E2-induced deoxyribonucleic acid degradation in spheroplast preparations. 459 17

A multiple mutant strain of Escherichia coli containing mutations affecting the exoribonucleases, RNase II, RNase D, and RNase BN, and also the endonuclease, RNase I, was constructed by P1-mediated transduction. Extracts of the mutant strain were lacking the aforementioned RNase activities. The multiple mutant displayed normal growth in both rich and minimal media at a variety of temperatures, recovered from starvation essentially as the wild-type parent, and could support the growth of a variety of bacteriophages. In addition, RNA synthesis was normal and no precursor RNA accumulation was observed. The properties of the mutant strain indicate that the three exoribonucleases are not essential for the viability of E. coli. The implications of these findings to our understanding of RNA processing and degradation are discussed.
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PMID:A multiple mutant of Escherichia coli lacking the exoribonucleases RNase II, RNase D, and RNase BN. 620 70

The specificity of transcription of Euglena gracilis Z chloroplast DNA by chloroplast DNA-dependent RNA polymerase in a transcriptionally active chromosome (Hallick, R.B., Lipper, C., Richards, O.C., and Rutter, W.J. (1976) Biochemistry 15, 3039-3045) has been studied. RNA molecules are both initiated and elongated in vitro. The RNA transcripts have been characterized as to their size, nuclease sensitivity, 5'-terminal oligonucleotides, and coding locus on the chloroplast genome. RNA labeled in vitro at the 5' end with [gamma-32P]ATP was digested with RNase T1, RNase A, and S1 nuclease. The resulting 5'-gamma-32P-oligonucleotides were fractionated by gel electrophoresis. In each case, one or two discrete products were obtained, consistent with initiation in vitro only at defined loci. RNA labeled in vitro with [alpha-32P]ATP or CTP has been hybridized to Southern (Southern, E.M. (1975) J. Mol. Biol. 98, 503-517) transfers of restriction endonuclease fragments of chloroplast DNA. The most abundant in vitro transcripts hybridize to chloroplast DNA fragments coding for 23 S, 16 S, and 5 S rRNAs. Only the coding strands of the rRNA genes are transcribed. Non-rDNA sequences of chloroplast DNA are also selectively transcribed but at much lower levels. The transcriptionally active chromosome has proved to be an ideal biochemical preparation for the study of selective transcription of cell organelle DNA.
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PMID:Selective in vitro transcription of Euglena chloroplast ribosomal RNA genes by a transcriptionally active chromosome. 676 27

Ribosomal proteins S1 when associated with the 30-S subunit does not interact with 16-S RNA but its binding is determined mostly by protein-protein interactions. These conclusions are based on the following data. 1. Ultraviolet irradiation (lambda = 254 nm) of the 30-S subunit does not result in the covalent cross-linking of S1 with 16-S RNA at irradiation doses up to 150 quanta/nucleotide, whereas the irradiation under the same conditions of S1 . polynucleotide complexes [S1 . poly(U), S1 . poly(A) and S1 . Q beta phage RNA] induces effective formation of polynucleotide-protein cross-links. 2. Mild treatment of 30-S subunits lacking S-1 with RNase A or with cobra venom endonuclease results in removal of 10--20% of the total nucleotide material but does not affect their sedimentation characteristics of their S1 binding capacity. 3. The association of S1 with S1-depleted 30-S subunits is insensitive to aurintricarboxylic acid, which is known as a strong inhibitor of complex formation between S1 and polynucleotides. 4. Mild trypsin treatment of S1-depleted 30-S subunits greatly reduces their S1 binding capacity.
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PMID:Ribosomal protein S1 associates with Escherichia coli ribosomal 30-S subunit by means of protein-protein interactions. 703 93

A study of the genetic variability of herpes simplex virus (HSV) type 1 from recurrent lesions and clinical reinfections was done using restriction endonuclease analysis and the RNase A mismatch cleavage method. Comparative genetic analyses of HSV-1 recurrent isolates from 1 patient and of HSV-1 isolates from different anatomic areas (vagina and lip) from another patient showed differences only in the glycoprotein B gene but not in the thymidine kinase gene even though the viruses had the same restriction endonuclease pattern. These results suggest the RNase A mismatch cleavage method is useful for epidemiologic studies of DNA viruses.
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PMID:Genetic analysis of herpes simplex virus type 1 isolates from recurrent lesions and clinical reinfections. 759 26

The regulation of mRNA half-lives is determined by multiple factors, including the activity of the messenger RNases (mRNases) responsible for destroying mRNA molecules. Previously, we used cell-free mRNA decay assays to identify a polysome-associated endonuclease that cleaves c-myc mRNA within the coding region. A similar activity has been solubilized and partially purified from a high salt extract of adult rat liver polysomes. Based on a correlation between protein and enzyme activity, the endonuclease is tentatively identified as a approximately 39-kDa protein. It cleaves the coding region stability determinant of c-myc mRNA with considerable specificity. Cleavages occur predominantly in an A-rich segment of the RNA. The endonuclease is resistant to RNase A inhibitors, sensitive to vanadyl ribonucleoside complex, and dependent on magnesium. In these and other respects, the soluble enzyme we have purified resembles the polysome-associated c-myc mRNase.
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PMID:Purification and characterization of a polysome-associated endoribonuclease that degrades c-myc mRNA in vitro. 973 91

Two cytotoxic proteins, bovine pancreatic ribonuclease A (RNase A), and a restriction endonuclease from Haemophilus parainfluenzae (HpaI), were produced using a novel semisynthetic approach that utilizes a protein splicing element, an intein, to generate a reactive thioester at the C-terminus of a recombinant protein. Nucleophilic attack on this thioester by the N-terminal cysteine of a synthetic peptide ultimately leads to the ligation of the two reactants through a native peptide bond. This strategy was used to produce RNase A and HpaI by isolating inactive truncated forms of these proteins, the first 109 and 223 amino acids of RNase A and HpaI, respectively, as fusion proteins consisting of the target protein, an intein, and a chitin binding domain. Thiol-induced cleavage of the precursor led to the liberation of the target protein with a C-terminal thioester-tag. Addition of synthetic peptides representing the amino acids missing from the truncated forms led to the generation of full-length products that displayed catalytic activity indicative of the wild-type enzymes. The turnover numbers and Km for ligated and renatured RNase A were 8.2 s(-1) and 1.5 mM, in good agreement with reported values of 8.3 s(-1) and 1.2 mM (Hodges & Merrifield, 1975). Ligated HpaI had a specific activity of 0.5-1.5 x 10(6) U/mg, which compared favorably with the expected value of 1-2 x 10(6) U/mg (J. Benner, unpubl. obs.). Besides assisting in the production of cytotoxic proteins, this technique could allow the easy insertion of unnatural amino acids into a protein sequence.
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PMID:Semisynthesis of cytotoxic proteins using a modified protein splicing element. 982 92

2-Methyl-4-carboxy,5-hydroxy-3,4,5,6-tetrahydropyri- midine (THP(A) or hydroxyectoine) and 2-methyl,4-carboxy-3,4,5, 6-tetrahydropyrimidine (THP(B) or ectoine) are now recognized as ubiquitous bacterial osmoprotectants. To evaluate the impact of tetrahydropyrimidine derivatives (THPs) on protein-DNA interaction and on restriction-modification systems, we have examined their effect on the cleavage of plasmid DNA by 10 type II restriction endonucleases. THP(A) completely arrested the cleavage of plasmid and bacteriophage lambda DNA by EcoRI endonuclease at 0.4 mM and the oligonucleotide (d(CGCGAATTCGCG))2 at about 4.0 mM. THP(B) was 10-fold less effective than THP(A), whereas for betaine and proline, a notable inhibition was observed only at 100 mM. Similar effects of THP(A) were observed for all tested restriction endonucleases, except for SmaI and PvuII, which were inhibited only partially at 50 mM THP(A). No effect of THP(A) on the activity of DNase I, RNase A, and Taq DNA polymerase was noticed. Gel-shift assays showed that THP(A) inhibited the EcoRI-(d(CGCGAATTCGCG))2 complex formation, whereas facilitated diffusion of EcoRI along the DNA was not affected. Methylation of the carboxy group significantly decreased the activity of THPs, suggesting that their zwitterionic character is essential for the inhibition effect. Possible mechanisms of inhibition, the role of THPs in the modulation of the protein-DNA interaction, and the in vivo relevance of the observed phenomena are discussed.
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PMID:Effect of tetrahydropyrimidine derivatives on protein-nucleic acids interaction. Type II restriction endonucleases as a model system. 1006 45

With the use of a high yield prokaryotic expression system, large amounts of human eosinophil cationic protein (ECP) have been obtained. This has allowed a thorough kinetic study of the ribonuclease activity of this protein. The catalytic efficiencies for oligouridylic acids of the type (Up)nU>p, mononucleotides U>p and C>p, and dinucleoside monophosphates CpA, UpA, and UpG have been interpreted by the specific subsites distribution in ECP. The distribution of products derived from digestion of high molecular mass substrates, such as poly(U) and poly(C), by ECP was compared with that of RNase A. The characteristic cleavage pattern of polynucleotides by ECP suggests that an exonuclease-like mechanism is predominantly favored in comparison to the endonuclease catalytic mechanism of RNase A. Comparative molecular modeling with bovine pancreatic RNase A-substrate analog crystal complexes revealed important differences in the subsite structure, whereas the secondary phosphate-binding site (p2) is lacking, the secondary base subsite (B2) is severely impaired, and there are new interactions at the po, Bo, and p-1 sites, located upstream of the P-O-5' cleavable phosphodiester bond, that are not found in RNase A. The differences in the multisubsites structure could explain the reduced catalytic efficiency of ECP and the shift from an endonuclease to an exonuclease-type mechanism.
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PMID:Kinetic and product distribution analysis of human eosinophil cationic protein indicates a subsite arrangement that favors exonuclease-type activity. 1033 57

Pancreatic ribonuclease A (RNase A) is a endonuclease that catalyzes depolymerization of ribonucleic acid (RNA) releasing oligonucleotides. In the process of binding enzyme with substrate are involved several non-catalytic phosphate binding subsites, one of them is p2, additional to main catalytic site p1. RNaza A prefers binding and cleavage of longer substrate molecules, and 3',5'-phosphodiester bond should be some six-seven residues apart from the end of molecules of the chain of RNA. In this work is analysed endonuclease activity of recombinant pancreatic RNase A (K7H), that in position seven instead of a lysine there is a histidine, amino acid residue that participates in main catalytic site p1. Mutant enzyme is obtained by site-directed mutagenesis by Kunkel. Results of this investigation have shown that substitution of lysine by histidine in position seven of RNase A has produced total deletion of p2 subsite, and K7H has lost endonuclease activity, and has become exonuclease. These results confirm central role of Lys-7 in establishing p2 subsite and endonuclease activity of pancreatic RNase A.
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PMID:[Endonuclease activity of recombinant pancreatic nuclease (A-K7H)]. 1038 39


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