The assembly of the complex that forms over the simian virus 40 origin to initiate DNA replication is not well understood. This complex is composed of the virus-coded T antigen and three cellular proteins, replication protein A (RPA), DNA polymerase alpha/primase (pol/prim) and topoisomerase I (topo I) in association with the origin. The order in which these various proteins bind to the DNA was...

Objective: The aim of this study was to determine the effects of residues at 228th positions of VIM-38 on minimum inhibition concentration (MIC) and molecular docking analysis. Materials and methods: blaVIM-38 gene was cloned into expression vector pET100/D-TOPO. Then pET100/D-TOPO-VIM-38 was used to generate the R228S mutation by site-directed mutagenesis. The mutant was transformed into E. co...

Protoberberine alkaloids (coralyne and its derivatives), which exhibit antileukemic activity in animal models, have been shown to be potent inducers of topoisomerase (topo) I-DNA cleavable complexes using punlied recombinant human DNA topo I. Different from the structurally similar benzophenanthridine alkaloid nitidine (a dual poison of both topos I and II), coralyne and its derivatives have ma...

Topoisomerases are essential nuclear enzymes that work to resolve topological problems that normally occur during DNA metabolism. Their involvement in crucial DNA associated-processes, such as replication, transcription and repair, mark them as a target of chemotherapeutic drugs such as camptothecins (CPTs). Therefore, finding other agents that may alter their activity is of great importance. P...

Protoberberine alkaloids (coralyne and its derivatives), which exhibit antileukemic activity in animal models, have been shown to be potent inducers of topoisomerase (topo) I-DNA cleavable complexes using purified recombinant human DNA topo I. Different from the structurally similar benzophenanthridine alkaloid nitidine (a dual poison of both topos I and II), coralyne and its derivatives have m...

The anticancer agent saintopin induces DNA cleavage mediated by both topoisomerase (topo) I and topo II in vitro through stabilization of the reversible enzyme-DNA cleavable complex. We established saintopinresistant cell lines (KB/STP-1 and KB/STP-2) from human epidermoid cancer KB cells by stepwise exposure to increasing doses of the drug. KB/STP-1 and KB/STP-2 cells showed 12and 44-fold incr...

Topoisomerase (topo)-I targeting antitumor agents are very effective in vivo against various human cancers. The indolocarbazole compound 6-N-formylamino-12,13-dihydro-1,11-dihydroxy-13-(beta-D-glucopyranosyl)- 5H-indolo[2,3-alpha]pyrrolo-[3,4-c]carbazole-5,7(6H)-dione (NB-506) is a potent inhibitor of the religation step of topo I reaction, like camptothecin (CPT). We established a NB-506-resis...

To understand the effects of the interaction between Mycoplasma and cells on the host cellular function, it is important to elucidate the influences of infection of cells with Mycoplasma on nuclear enzymes such as DNA Topoisomerase type I (Topo I). Human Topo I participates in DNA transaction processes and is the target of anti-cancer drugs, the camptothecins (CPTs). Here we investigated the me...

Changes in topoisomerase I (topo I) levels and localization were exam ined during the course of granulocytic maturation in vitro and in vivo. Western blotting revealed that granulocytic maturation in DMSO-treated III.-6(1 human leukemia cells was accompanied by a 5-fold decrease in topo I polypeptide content. Consistent with this result, 3to 5-fold higher concentrations of the topo I poison cam...

The anticancer agent saintopin induces DNA cleavage mediated by both topoisomerase (topo) I and topo II in vitro through stabilization of the reversible enzyme-DNA cleavable complex. We established saintopin-resistant cell lines (KB/STP-1 and KB/STP-2) from human epidermoid cancer KB cells by stepwise exposure to increasing doses of the drug. KB/STP-1 and KB/STP-2 cells showed 12- and 44-fold i...