Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:6.2.1.7 (BAL)
 1,977 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The nucleoprotein structure of telomeres from Euplotes crassus was studied by using nuclease and chemical footprinting. The macronuclear telomeres were found to exist as DNA-protein complexes that are resistant to micrococcal nuclease digestion. Each complex encompassed 85 to 130 base pairs of macronuclear DNA and appeared to consist of two structural domains that are characterized by dissimilar DNA-protein interactions. Dimethyl sulfate footprinting demonstrated that very sequence-specific and salt-stable interactions occur in the most terminal region of each complex. DNase I footprinting indicated that DNA in the region 30 to 120 base-pairs from the 5' end lies on a protein surface; the interactions in this region of the complex are unlikely to be sequence specific. A 50-kilodalton telomere-binding protein was isolated. Binding of this protein protected telomeric DNA from BAL 31 digestion and gave rise to many of the sequence-specific DNA-protein interactions that were observed in vivo. The telomeric complexes from E. crassus were very similar in overall structure to the complexes found at Oxytricha telomeres. However, telomeric complexes from the two ciliates showed significant differences in internal organization. The telomeric DNA, the telomere-binding proteins, and the resultant DNA-protein interactions were all somewhat different. The telomere-binding proteins from the two ciliates were found to be less closely conserved than might have been expected. It appears that the proteins are tailored to match their cognate telomeric DNA.
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PMID:Telomere structure in Euplotes crassus: characterization of DNA-protein interactions and isolation of a telomere-binding protein. 235 12

Abnormal tubulofilamentous structures have been identified in electron micrographs of thin sections and negatively stained impression grids prepared from brains of animals with scrapie and other spongiform encephalopathies, and we showed that such tubules contain a core of filamentous structures resembling scrapie-associated fibrils (SAF). We treated impression grids from brains of scrapie-infected hamsters with several substances that bind to or cleave proteins and nucleic acids to see if they had any effect on the abnormal tubulofilamentous structures. Treatment with three proteolytic enzymes reduced the caliber of the tubules from about 50 nm to 30 nm; subsequent treatment of the 30-nm tubules with DNase I left many typical SAF as well as transitional forms in which twisted SAF emerged from tubules. DNase treatment of the original thicker tubules had no effect, and no SAF were seen on grids. Treatment of the 30-nm tubules with any of three other nucleases (micrococcal, mung bean, and BAL-31) also produced SAF. However, treatment with RNase A had no effect either on the original 50-nm tubules or on the 30-nm tubules produced by proteolysis. Detergent treatment of any of the preparations produced SAF. Treatment with ethidium bromide resulted in staining of the tubules that was inhibited by magnesium ions. The data suggest that the abnormal tubulofilamentous particles found in spongiform encephalopathies may consist of an outer cylinder of protein, an inner cylinder of DNA, and an innermost core of SAF.
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PMID:Evidence that DNA is present in abnormal tubulofilamentous structures found in scrapie. 313 Jun 30

We describe a system to generate cDNA or genomic libraries from DNA segments that have blunt termini. Background and rearrangement levels are low, but efficiencies are high and the procedural times very short. T4 ligase in the presence of polyethylene glycol produces high Mr oligomers of vector and insert. These concatemers are reduced to vector-insert monomers at a high frequency by subsequent cleavage with a restriction endonuclease, which recognises the insert rarely, if at all, and the vector once. The monomers are recircularised under standard ligation conditions prior to transformation. Thus insertion conditions are optimised independently of those for recircularisation. All reading frames for expression libraries are generated by short BAL 31 cleavage followed by the blunt-end cloning procedure. Similarly, genomic expression libraries can be made by BAL 31 or mung-bean nuclease treatment after cleavage with DNase I is the presence of Mn2+. The technique is suitable for any DNA segment that is blunt-ended or can be made so. When the vector is treated with alkaline phosphatase, recombinants are generated at a frequency greater than 90% and have single inserts. Yields are 3-5 X 10(6) colony-forming units per micrograms of insert.
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PMID:Rapid and efficient method for cloning of blunt-ended DNA fragments. 359 40

The systemic pharmacological treatment of disease is limited by severe toxicity to normal organs/tissue. Therefore, various delivery vehicles have been designed to carry therapeutic drugs to their target tissues. We designed a novel vehicle formed by the interaction of biotins in a DNA (polymer) with avidins (crosslink), resulting in a porous particle. This self-assembled (HSAM) nanoparticle vehicle has been tested in our laboratory both in vitro and in vivo for its ability to carry doxorubicin, a widely used anticancer drug with a high toxicity to normal organs. Doxorubicin binds to the nanoparticle by intercalating into the DNA strands that are later degraded by nucleases released from cancer cells. Our results showed that 1.1 microg of HSAM DNA can carry 1 microg of doxorubicin, and the doxorubicin-bound HSAM nanoparticle can still be degraded by nucleases (BAL-31 and DNase I). The HSAM nanoparticle carrying doxorubicin can efficiently inhibit cancer cell growth in vitro and in a murine model. Furthermore, this nanoparticle is able to deliver up to 180 ng/mg of doxorubicin to the target tumor tissue, which is 15-fold above the systemic toxicity dose (12 mg/kg). These results suggest that the HSAM nanoparticle is both biocompatible and biodegradable, making it a valuable vehicle for drug delivery in cancer treatment.
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PMID:Novel biodegradable HSAM nanoparticle for drug delivery. 1652 85

Reaction conditions for numerous endonucleases are detailed in this unit along with discussions of potential applications. Specific enzymes include BAL 31 nuclease, S1 nuclease, mung bean nuclease, micrococcal nuclease and DNase I.
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PMID:Endonucleases. 1826 21

Reaction conditions for a variety of endonucleases are detailed in this unit along with discussions of potential applications. Enzymes covered include BAL 31 nuclease, S1 nuclease, mung bean nuclease, micrococcal nuclease, and DNase I. A general discussion regarding the use of endonucleases to generate nonspecific breaks in dsDNA is also provided. For a detailed discussion of the endonucleases more typically associated with DNA damage repair (e.g., Endo III, IV, V and VIII of E. coli and human APE1), see UNIT 3.9.
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PMID:Endonucleases. 2122 39