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:4.1.99.3 (PRE)
1,923 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Swine genomic DNA segments containing repetitive sequences were isolated from a porcine genomic library using genomic DNA as a probe. Three fragments containing the repetitive sequences from two of the primary phage clones were subcloned for sequence analysis, which revealed six new PRE-1 repetitive families other than those reported earlier by Singer et al. (Nucleic Acids Research 15, 2780, 1987). The frequency of the repetitive sequences in the swine genome was estimated at 2 x 10(6) per diploid genome. Sequence analysis revealed similarities between these repetitive sequences and that of arginine-tRNA gene.
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PMID:Characterization of swine short interspersed repetitive sequences. 141 50

Escherichia coli DNA photolyase repairs pyrimidine dimers by a photoinduced electron-transfer reaction. The enzyme binds to UV-damaged DNA independent of light (the dark reaction) and upon absorbing a 300-500-nm photon breaks the cyclobutane ring of the dimer (the light reaction) and thus restores the DNA. No structural information on the enzyme is available at present. However, comparison of the sequences of photolyases from five different organisms has identified highly conserved regions of homology. These regions are presumably involved in chromophore (flavin and folate) and substrate binding or catalysis. Trp277 (W277) in E. coli photolyase is conserved in all photolyases sequenced to date. We replaced this residue with Arg, Glu, Gln, His, and Phe by site-specific mutagenesis. Properties of the mutant proteins indicate that W277 is involved in binding to DNA but not in chromophore binding or catalysis. Of particular significance is the finding that compared to wild type W277R and W277E mutants have about 300- and 1000-fold lower affinity, respectively, for substrate but were indistinguishable from wild-type enzyme in their photochemical and photocatalytic properties.
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PMID:Active site of Escherichia coli DNA photolyase: mutations at Trp277 alter the selectivity of the enzyme without affecting the quantum yield of photorepair. 220 May 11

Butane-2,3-dione inhibits the enzymic activity of Streptomyces griseus photoreactivating enzyme (PRE). Some characteristics of the inhibition, notably the enhancement by borate buffer and the reversibility, indicate that arginine residues are modified. From the kinetics of inhibition it can be concluded that a single essential arginine residue is involved. U.v.-irradiated DNA, the substrate for PRE, protects the enzyme against inactivation by butane-2,3-dione. This suggests that the essential arginine residue is situated in or near the u.v.-irradiated-DNA-binding site. Non-irradiated DNA at higher concentrations also protects against inactivation, indicating that PRE can form non-specific complexes. From the ratio of complex constants obtained from protection experiments with non-irradiated and u.v.-irradiated DNA it appears that PRE preferably binds to dimer sites.
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PMID:Evidence for the presence of an essential arginine residue in photoreactivating enzyme from Streptomyces griseus. 392 71

We have purified large quantities of Escherichia coli photoreactivating enzyme (EC 4.1.99.3) to apparent homogeneity and have studied its physical and chemical properties. The enzyme has a molecular weight of 36 800 and a S020,W of 3.72 S. Amino acid analysis revealed an apparent absence of tryptophan, a low content of aromatic residues, and the presence of no unusual amino acids. The N terminus is arginine. The purified enzyme contained up to 13% carbohydrate by weight. The carbohydrate was composed of mannose, galactose, glucose, and N-acetylglucosamine. The enzyme is also associated with RNA (approximately 10 nucleotides/enzyme molecule) containing uracil, adenine, guanine, and cytosine with no unusual bases detected.
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PMID:Escherichia coli photoreactivating enzyme: purification and properties. 677 46

Paeoniae Radix (the roots of Paeonia lactiflora Pallas) is a crude drug that is used in Asia and Europe to improve blood flow. We studied its vasodilator effect and mechanisms of action in vitro. The extract from Paeoniae Radix (PRE) relaxed prostaglandin F2a-precontracted aortic ring preparations of isolated rat aorta that contained endothelium. Relaxation by PRE did not occur in specimens without endothelium, and was inhibited by pretreatment with 10(-4) M NG-nitro-1-arginine methyl ester. Paeoniflorin and paeonol, the main active components of Paeoniae Radix, lacked a vasodilator effect. The effect of the component gallotannin was examined after treating PRE with tannase, but the product lacked a vasodilator effect. Pentagalloylglucose, hexagalloylglucose, heptagalloylglucose, and octagalloylglucose were extracted from PRE; they relaxed aortic rings with endothelium, but failed to relax aortic rings without endothelium. We conclude that PRE exhibits an endothelium-dependent vasodilator effect on isolated rat aorta. The active component is gallotannin.
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PMID:Endothelium-dependent vasodilator effect of extract prepared from the roots of Paeonia lactiflora on isolated rat aorta. 892 10

Several novel (sub)families of SINEs were isolated from the genomes of cetaceans and artiodactyls, and their sequences were determined. From comparisons of diagnostic nucleotides among the short interspersed repetitive elements (SINEs) in these (sub)families, we were able to draw the following conclusions. (1) After the divergence of the suborder Tylopoda (camels), the CHRS family of SINEs was newly created from tRNA(Glu) in a common ancestor of the lineages of the Suina (pigs and peccaries), Ruminantia (cows and deer), and Cetacea (whales and dolphins). (2) After divergence of the Suina lineage, the CHR-1 SINE and the CHR-2 SINE were generated successively in a common ancestor of ruminants, hippopotamuses, and cetaceans. (3) In the Ruminantia lineage, the Bov-tA SINE was generated by recombination between the CHR-2 SINE and Bov-A. (4) In the Suina lineage, the CHRS-S SINE was generated from the CHRS SINE. (5) In this latter lineage, the PRE-1 family of SINEs was created by insertion of part of the gene for tRNA(Arg) into the 5' region of the CHRS-S family. The distribution of a particular family of SINEs among species of artiodactyls and cetaceans confirmed the most recent conclusion for paraphyly of the order Artiodactyla. The present study also revealed that a newly created tRNA(Glu)-derived family of SINEs was subjected both to recombination with different units and to duplication of an internal sequence within a SINE unit to generate, during evolution, a huge superfamily of tRNA(Glu)-related families of SINEs that are now found in the genomes of artiodactyls and cetaceans.
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PMID:Genealogy of families of SINEs in cetaceans and artiodactyls: the presence of a huge superfamily of tRNA(Glu)-derived families of SINEs. 1047 1

Growing evidence indicates that reactive oxygen species (ROS) as well as nitric oxide (NO) have a profound influence on contractile function of skeletal muscle possibly through modulation of excitation-contraction coupling. We hypothesized that if NO and xanthine oxidase (XO) interact at key sites in excitation-contraction coupling, the effects of XO with nitric oxide synthase (NOS) inhibitors and NO donors on contractile function of the unfatigued diaphragm would not be additive. Diaphragm fibre bundles were extracted from 4-month Fischer-344 rats and placed in Krebs solution bubbled with 95% O2, 5% CO2. Baseline twitch tension, tension at 20 Hz (low-frequency), and maximal tetanic tension (Po) at 120 Hz were then measured (PRE). In Experiment 1 diaphragm fibre bundles were exposed to Krebs with 200 microM hypoxanthine as a control (CON); 0.02 U mL-1 XO + 200 microM hypoxanthine; 1 mM of the NOS inhibitor N-nitro-L-arginine (L-NNA) or L-NNA + XO. Five minutes were allowed for equilibration, and a second set of contractile measures was taken (POST). In Experiment 2 we exposed diaphragm fibre bundles to one of the following four solutions: CON, XO, 100 microM of the NO donor sodium nitroprusside (SNP) and XO + SNP, and evaluated contractile function as described above. In Experiment 3 we tested to determine if peroxynitrite production from the reaction of superoxide anion and NO affected the above results for SNP using 30 microM ebselen as a peroxynitrite quencher. Xanthine oxidase resulted in a significant potentiation of diaphragm twitch tension and tension at 20 Hz (+29%) without affecting Po. L-NNA also significantly increased 20 Hz tension but did not alter Po. However, the combination of XO + L-NNA did not further increase low-frequency contractility. Sodium nitroprusside alone did not affect diaphragm contractility, but did attenuate XO-induced potentiation in the XO + SNP group. Ebselen did not alter the impact of SNP on XO in the diaphragm. These data support the hypothesis that XO and NO interact or compete at similar sites of action that modulate contractility of the unfatigued diaphragm.
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PMID:Interaction of nitric oxide and reactive oxygen species on rat diaphragm contractility. 1088 37

Cyclobutane pyrimidine dimer (CPD) photolyases, which contain FAD as a cofactor, use light to repair CPDs. We performed structural analyses of the catalytic site of the Thermus thermophilus CPD photolyase-DNA complex, using FAD-induced paramagnetic relaxation enhancement (PRE). The distances between the tryptophan residues and the FAD calculated from the PRE agree well with those observed in the x-ray structure (with an error of <3 A). Subsequently, a single-stranded DNA containing 13C-labeled CPD was prepared, and the FAD-induced PRE of the NMR resonances from the CPD lesion in complex with the CPD photolyase was investigated. The distance between the FAD and the CPD calculated from the PRE is 16 +/- 3 A. The FAD-induced PRE was also observed in the CPD photolyase-double-stranded DNA complex. Based on these results, a model of the CPD photolyase-DNA complex was constructed, and the roles of Arg-201, Lys-240, Trp-247, and Trp-353 in the CPD-repair reaction are discussed.
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PMID:NMR study of repair mechanism of DNA photolyase by FAD-induced paramagnetic relaxation enhancement. 1546 18

There is a cultivar difference in the response to ultraviolet-B (UVB: 280-320 nm) in rice (Oryza sativa L.). Among Japanese lowland rice cultivars, Sasanishiki, a leading Japanese rice cultivar, is resistant to the damaging effects of UVB while Norin 1, a close relative, is less resistant. We found previously that Norin 1 was deficient in cyclobutane pyrimidine dimer (CPD) photorepair ability and suggested that the UVB sensitivity in rice depends largely on CPD photorepair ability. In order to verify that suggestion, we examined the correlation between UVB sensitivity and CPD photolyase activity in 17 rice cultivars of progenitors and relatives in breeding of UV-resistant Sasanishiki and UV-sensitive Norin 1. The amino acid at position 126 of the deduced amino acid sequence of CPD photolyase in cultivars including such as Norin 1 was found to be arginine, the CPD photolyase activities of which were lower. The amino acid at that position in cultivars including such as Sasanishiki was glutamine. Furthermore, cultivars more resistant to UVB were found to exhibit higher photolyase activities than less resistant cultivars. These results emphasize that single amino acid alteration from glutamine to arginine leads to a deficit of CPD photolyase activity and that CPD photolyase activity is one of the main factors determining UVB sensitivity in rice.
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PMID:Ultraviolet-B sensitivities in Japanese lowland rice cultivars: cyclobutane pyrimidine dimer photolyase activity and gene mutation. 1565 3

X-ray crystallographic and functional analysis of the class I DNA photolyase from Thermus thermophilus revealed the binding of flavin mononucleotide (FMN) as an antenna chromophore. The binding mode of FMN closely coincides with the binding of a deazaflavin-like chromophore in the related class I DNA photolyase from Anacystis nidulans. Compared to the R46E mutant, which lacks a conserved arginine in the binding site for the antenna chromophore, the FMN-comprising holophotolyase exhibits an eightfold higher activity at 450 nm. The facile incorporation of the flavin cofactors 8-hydroxy-deazariboflavin and 8-iodo-8-demethyl-riboflavin into the binding site for the antenna chromophore paves the way for wavelength-tuning of the activity spectra of DNA photolyases by using synthetic flavins.
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PMID:Natural and non-natural antenna chromophores in the DNA photolyase from Thermus thermophilus. 1705 59


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