Tricky Topology: Persistence of Folded Human Telomeric i-Motif DNA at Ambient Temperature and Neutral pH

Abdelhamid, Mahmoud and Waller, Zoe (2020) Tricky Topology: Persistence of Folded Human Telomeric i-Motif DNA at Ambient Temperature and Neutral pH. Frontiers in Chemistry, 8. ISSN 2296-2646

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Abstract

i-Motifs are four-stranded DNA structures formed from sequences rich in cytosine, held together by hemi-protonated cytosine-cytosine base pairs. These structures have been utilized extensively as pH-switches in DNA-based nanotechnology. Recently there has been an increasing interest in i-motif structures in biology, fuelled by examples of when these can form under neutral conditions. Herein we describe a cautionary tale regarding handling of i-motif samples. Using CD and UV spectroscopy we show that it is important to be consistent in annealing i-motif DNA samples as at neutral pH, i-motif unfolding kinetics is dependent on the time allowed for annealing and equilibration. We describe how the quadruplex structure formed by the human telomeric i-motif sequence can be shown to form and persist in the same conditions of neutral pH and ambient temperature in which, once at thermodynamic equilibrium, it exists predominantly as a random coil. This study has implications not only for work with i-motif DNA structures, but also in the uses and applications of these in nanotechnological devices.

Item Type: Article
Additional Information: Copyright © 2020 Abdelhamid and Waller.
Uncontrolled Keywords: i-motif,cytosine,quadruplex,dna,topology,kinetics
Faculty \ School: Faculty of Science > School of Pharmacy
Related URLs:
Depositing User: LivePure Connector
Date Deposited: 12 Feb 2020 05:38
Last Modified: 26 Jul 2020 23:48
URI: https://ueaeprints.uea.ac.uk/id/eprint/74158
DOI: 10.3389/fchem.2020.00040

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