Antibacterial fluoroquinolones trap a cleavage complex of gyrase and topoisomerase (topo) IV inducing site-specific DNA breakage within a bent DNA gate engaged in DNA transport. Despite its importance for drug action and in revealing potential sites of topoisomerase catalysis, the mechanism of DNA selectivity is poorly understood. To explore its functional basis, we generated mutant versions of...

In this study at first , an azo dye, 2,7- naphthalenediol, 2-[(4-Bromophenyl)azo (BPAND) as a ligand has been synthesized by addition of p-Bromoaniline to the modified montomorillonite K10 clay. This ligand was characterized using 1H-NMR, UV-Vis and IR spectroscopies. Subsequently, its interaction with calf thymus deoxyribonucleicacid ,ct-DNA was investigated in 5 mM phosphate buffer solution, ...

We recently used in vitro selection to identify many deoxyribozymes that catalyze DNA phosphodiester bond hydrolysis and create 5'-phosphate and 3'-hydroxyl termini. Alternatively, numerous deoxyribozymes have been identified for catalysis of RNA cleavage by 2'-hydroxyl transesterification, forming 2',3'-cyclic phosphate and 5'-hydroxyl termini. In this study, we investigated the ability of DNA...

This paper encourages understanding a non-invasive technology—the “Liquid biopsy”, including circulating tumor cells (CTCs) and DNA (ct DNA) technology, that can help diagnose early cancers, cancer relapse, resistance to chemotherapy. reviews various CTCs ct studies in the literature about their applications gynecological cancers. Hopefully, further translational research gynecology will enable...

Cleavage specificity of RNase HI was examined on model Okazaki fragments, to determine the likely role of this nuclease in lagging strand DNA replication. Each substrate was prepared by annealing a short RNA primer, made by transcription in vitro, to a single-stranded synthetic DNA template, and subsequently extending the primer by DNA polymerization. The calf thymus RNase HI makes a structure-...

The BcgI restriction-modification system consists of two subunits, A and B. It is a bifunctional protein complex which can cleave or methylate DNA. The regulation of these competing activities is determined by the DNA substrates and cofactors. BcgI is an active endonuclease and a poor methyltransferase on unmodified DNA substrates. In contrast, BcgI is an active methyltransferase and an inactiv...

Traditional methods to assay enzymatic cleavage of DNA are discontinuous and time consuming. In contrast, recently developed fluorescence methods are continuous and convenient. However, no fluorescence method has been developed for single-stranded DNA digestion. Here we introduce a novel method, based on molecular beacons, to assay single-stranded DNA cleavage by single strand-specific nuclease...

FokI is a member an unusual class of restriction enzymes that recognize a specific DNA sequence and cleave nonspecifically a short distance away from that sequence. FokI consists of an N-terminal DNA recognition domain and a C-terminal cleavage domain. The bipartite nature of FokI has led to the development of artificial enzymes with novel specificities. We have solved the structure of FokI to ...

DNA cleavage stimulated by different topolsomerase H inhibitors shows in vitro a characteristic sequence specificity. Since chromatin struc tare and genome organization are expected to Influence drug-enzyme interactions and repair of drug-Induced DNA lesions, we investigated topoisomerase II DNA cleavage sites stimulated by teniposide (VM-26), 4-demethoxy-3'-deamino-3'-hydroxy-4'-epi-doxorubici...