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The impact of the C-terminal domain on the interaction of human DNA topoisomerase II α and β with DNA

Gilroy, K.L., and Austin , C.A. (2011) The impact of the C-terminal domain on the interaction of human DNA topoisomerase II α and β with DNA. PLoS ONE, 6 (2). e14693. ISSN 1932-6203 (doi:10.1371/journal.pone.0014693)

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Abstract

Background Type II DNA topoisomerases are essential, ubiquitous enzymes that act to relieve topological problems arising in DNA from normal cellular activity. Their mechanism of action involves the ATP-dependent transport of one DNA duplex through a transient break in a second DNA duplex; metal ions are essential for strand passage. Humans have two isoforms, topoisomerase IIα and topoisomerase IIβ, that have distinct roles in the cell. The C-terminal domain has been linked to isoform specific differences in activity and DNA interaction. Methodology/Principal Findings We have investigated the role of the C-terminal domain in the binding of human topoisomerase IIα and topoisomerase IIβ to DNA in fluorescence anisotropy assays using full length and C-terminally truncated enzymes. We find that the C-terminal domain of topoisomerase IIβ but not topoisomerase IIα affects the binding of the enzyme to the DNA. The presence of metal ions has no effect on DNA binding. Additionally, we have examined strand passage of the full length and truncated enzymes in the presence of a number of supporting metal ions and find that there is no difference in relative decatenation between isoforms. We find that calcium and manganese, in addition to magnesium, can support strand passage by the human topoisomerase II enzymes. Conclusions/Significance The C-terminal domain of topoisomerase IIβ, but not that of topoisomerase IIα, alters the enzyme's KD for DNA binding. This is consistent with previous data and may be related to the differential modes of action of the two isoforms in vivo. We also show strand passage with different supporting metal ions for human topoisomerase IIα or topoisomerase IIβ, either full length or C-terminally truncated. They all show the same preferences, whereby Mg > Ca > Mn.

Item Type:Article
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Gilroy, Dr Kathryn
Authors: Gilroy, K.L., and Austin , C.A.
Subjects:Q Science > QH Natural history
College/School:College of Medical Veterinary and Life Sciences > Institute of Infection Immunity and Inflammation > Centre for Virus Research
Journal Name:PLoS ONE
Publisher:Public Library of Science
ISSN:1932-6203
Published Online:16 February 2011
Copyright Holders:Copyright © 2011 The Authors
First Published:First published in PLoS ONE 6(2)
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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