DNA topoisomerase VI: characterisation and investigation as a target for inhibitors

Allen, Adam (2023) DNA topoisomerase VI: characterisation and investigation as a target for inhibitors. Doctoral thesis, University of East Anglia.

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Novel antimicrobials that target Plasmodium falciparum, the causative agent of severe malaria, are needed to combat widespread drug resistance. Herbicide resistance is also prevalent and poses a substantial threat to global crop production. DNA topoisomerases (topos) are a group of enzymes that regulate the topological state of DNA during vital cell processes such as DNA replication and transcription. Because of their fundamental cellular importance, topos are major molecular targets for chemotherapeutic and antimicrobial drugs. Topo VI is found ubiquitously in archaea and plants, where it plays critical roles in chromosome segregation and endoreduplication, respectively. Topo VI is also found sporadically in bacteria, algae, and other protists, but it is unclear whether the putative topo VI genes present in Plasmodium constitute a canonical topo VI complex. The present study features a series of bioinformatic and biochemical approaches to improve our knowledge of topo VI, and to determine its suitability as a target for inhibitors. Phylogenetic analysis has been used to show that topo VI is widely distributed across all three domains of life but is not present in Plasmodium. Furthermore, a coupled ATPase assay has shown that the rate of ATP hydrolysis by topo VI from the archaeon Methanosarcina mazei (MmTopo VI) is enhanced ~2-fold in the presence of positively-supercoiled DNA over that in the presence of negatively-supercoiled DNA. A novel high-throughput relaxation assay was also developed that has identified two potent inhibitors of MmTopo VI and yeast topo II. MmTopo VI is a useful model for the study of eukaryotic topo VI, and the plant enzyme should be pursued as a target for herbicides.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Nicola Veasy
Date Deposited: 07 Jun 2023 10:53
Last Modified: 07 Jun 2023 10:53
URI: https://ueaeprints.uea.ac.uk/id/eprint/92305


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