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DNA Cleavage Activity (dna + cleavage_activity)
Selected AbstractsEfficient Increase of DNA Cleavage Activity of a Diiron(III) Complex by a Conjugating Acridine GroupEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 34 2007Xiao-Qiang Chen Abstract A new diferric complex, Fe2Lb, in which a DNA intercalator (acridine) is linked to a precursor diferric complex (Fe2La), has been designed and synthesised as a hydrolytic cleaving agent of DNA. Compared with Fe2La (without the DNA intercalator) (La: 2,6-bis{[(2-hydroxybenzyl)(pyridin-2-yl)methylamino]methyl}-4-methylphenol), Fe2Lb [Lb: 5-(acridin-9-yl)- N -(3,5-bis{[(2-hydroxybenzyl)(pyridin-2-yl)methylamino]methyl}-4-hydroxybenzyl)pentanamide] leads to a 14-fold increase in the cleavage efficiency of plasmid DNA due to the binding interaction between DNA and the acridine moiety. The interaction has been demonstrated by UV/Vis absorption, CD spectroscopy, viscidity experiments and thermal denaturation studies. The hydrolytic mechanism is supported by evidence from T4 DNA ligase assay, reactive oxygen species (ROS) quenching and BNPP [bis(4-nitrophenyl) phosphate, a DNA model] cleavage experiments. The pH dependence of the BNPP cleavage by Fe2La in aqueous buffer media shows a bell-shaped pH,kobs profile with an optimum point around a pH of 7.0 which is in good agreement with the maximum point of the pH-dependent relative concentration curve of active species from the pH titration experiments. The determination of the initial rates at a pH of 7.36 as a function of substrate concentration reveals saturation kinetics with Michaelis,Menten-like behaviour and Fe2La shows a rate acceleration increase of 4.7,×,106 times in the hydrolysis of BNPP. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] ChemInform Abstract: Synthesis and DNA Cleavage Activity of 4,2,:4,,4,,:2,,,4,,,-Quaterthiazoles.CHEMINFORM, Issue 40 2008Hideaki Sasaki Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] An allosteric DNAzyme with dual RNA-cleaving and DNA-cleaving activitiesFEBS JOURNAL, Issue 11 2010Dazhi Jiang A series of RNA-cleaving or DNA-cleaving DNAzymes have been obtained by in vitro selection. However, engineering an allosteric DNAzyme with dual RNA-cleaving and DNA-cleaving activities is very challenging. We used an in vitro -selected pistol-like (PL) DNAzyme as a DNA scaffold for designing a DNAzyme with dual catalytic activities. We prepared the 46-nucleotide DNAzyme with DNA-cleaving activity (PL DNAzyme), and then grafted the deoxyribonucleotide residues from an 8,17 variant DNAzyme into the region of stem,loop I and the catalytic core of the PL DNAzyme scaffold. This deoxyribonucleotide residue grafting resulted in a DNAzyme with dual RNA-cleaving and DNA-cleaving activities (DRc DNAzyme). Drc DNAzyme has properties different from those of the original PL DNAzyme, including DNA cleavage sites and the required metal ion concentration. Interestingly, the RNA substrate and RNase A can act as effectors to mediate the DNA cleavage. Our results show that RNA-cleaving and DNA-cleaving activities simultaneously coexist in DRc DNAzyme, and the DNA cleavage activity can be reversibly regulated by a conformational transition. [source] Synthesis, DNA-Binding, Cleavage, and Cytotoxic Activity of New 1,7-Dioxa-4,10-diazacyclododecane Artificial Receptors Containing Bisguanidinoethyl or Diaminoethyl Double Side ArmsCHEMISTRY - A EUROPEAN JOURNAL, Issue 34 2007Xin Sheng Abstract Novel 1,7-dioxa-4,10-diazacyclododecane artificial receptors with two pendant aminoethyl (3) or guanidinoethyl (4) side arms have been synthesized. Spectroscopy, including fluorescence and CD spectroscopy, of the interactions of 3, 4, and their copper(II) complexes with calf thymus DNA indicated that the DNA binding affinity of these compounds follows the order Cu2+,4>Cu2+,3>4>3, and the binding constants of Cu2+,3 are Cu2+,4 are 7.2×104 and 8.7×104,M,1, respectively. Assessment by agarose gel electrophoresis of the plasmid pUC,19 DNA cleavage activity in the presence of the receptors showed that the complexes Cu2+,3 and Cu2+,4 exhibit powerful supercoiled DNA cleavage efficiency. Kinetic data of DNA cleavage promoted by Cu2+,3 and Cu2+,4 under physiological conditions fit to a saturation kinetic profile with kmax values of 0.865 and 0.596,h,1, respectively, which give about 108 -fold rate acceleration over uncatalyzed supercoiled DNA. This acceleration is due to efficient cooperative catalysis of the copper(II) center and the functional (diamino or bisguanidinium) groups. In-vitro cytotoxic activities toward murine melanoma B16 cells and human leukemia HL-60 cells were also examined: Cu2+,4 shows the highest activity with IC50 values of 1.62×10,4 and 1.19×10,5,M, respectively. [source] | ||||||||||