topoisomerases


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topoisomerases

Enzymes that assist in the topological manipulation of DNA. Before DNA can replicate it must be unwound. This occurs in short segments and is achieved by a Type I topoisomerase that cuts one strand so that the free end can be rotated around the unbroken strand. Topoisomerase 1 then re-ligates the broken strand. Type II topoisomerases cut both strands. The term is pronounced ‘topo-isomerase’. The derivation is Greek, topos , a place; iso , equal; meros , a part; with the -ase suffix denoting an enzyme.
References in periodicals archive ?
DNA topoisomerases and their poisoning by anticancer and antibacterial drugs.
Background: To investigate the role of a topoisomerase I inhibitor (topotecan) in chemoresistant ovarian cancer-initiating cells.
This study could also explain why some people with mutations in topoisomerases develop autism and other neurodevelopmental disorders.
Our study shows the magnitude of what can happen if topoisomerases are impaired," said senior study author Mark Zylka, PhD, associate professor in the Neuroscience Center and the Department of Cell Biology and Physiology at UNC.
Previous studies (42) have demonstrated that changes in topoisomerases are insufficient to explain the level of resistance to quinolones in S.
Evodiamine, a dual catalytic inhibitor of type 1 and 11 topoisomerases, exhibits enhanced inhibition against camptothecin resistant cells.
Continuing with the bioprospection study on the flora from La Marcada Natural Regional Park (LMNRP, Risaralda, Colombia) as a source of new secondary metabolites with diverse grade of biological activities and taking in consideration the fact that there is still great interest in finding novel and better inhibitory agents against topoisomerases or with antioxidant activities, prompted us to screen n-hexane, dichloromethane and aqueous-methanol crude extracts belonging to the selected families collected to study these activities.
Specific examples are topoisomerases that belong to the nuclear DNA replication and RNA transcription machinery, where they are key components in DNA-RNA synthesis.
Topoisomerases are essential enzymes in cell proliferation in all organisms.
Topoisomerases are already targets for several drugs including anti-tumour drugs and antibiotics, such as ciprofloxacin--the anti-anthrax drug.
Topoisomerases are a unique group of enzymes that untangle chromosomal DNA in the process of cell division, cut gaps in one strand of double stranded DNA, pass the other strand through the gap and subsequently reseal the break.
Cozzarelli elucidated the nature of DNA architecture and growth through enzymologic studies of polymerases, ligases, recombinases, and topoisomerases.