Identification of new DNA i-motif binding ligands through a fluorescent intercalator displacement assay

Qiran Sheng, Joseph C. Neaverson, Tasnim Mahmoud, Clare E. M. Stevenson, Susan E. Matthews, Zoë A. E. Waller

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i-Motifs are quadruplex DNA structures formed from sequences rich in cytosine and held together by intercalated, hemi-protonated cytosine–cytosine base pairs. These sequences are prevalent in gene promoter regions and may play a role in gene transcription. Targeting these structures with ligands could provide a novel way to target genetic disease but there are very few ligands which have been shown to interact with i-motif DNA. Fluorescent intercalator displacement (FID) assays are a simple way to screen ligands against DNA secondary structures. Here we characterise how thiazole orange interacts with i-motif DNA and assess its ability for use in a FID assay. Additionally, we report FID-based ligand screening using thiazole orange against the i-motif forming sequence from the human telomere to reveal new i-motif binding compounds which have the potential for further development.
Original languageEnglish
Pages (from-to)5669-5673
Number of pages5
JournalOrganic & Biomolecular Chemistry
Issue number27
Early online date1 Jun 2017
Publication statusPublished - 21 Jul 2017

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