Date of Award

Spring 2013

Document Type

Thesis

Terms of Use

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Degree Name

Bachelor of Arts

Department

Chemistry & Biochemistry

First Advisor

Liliya A. Yatsunyk

Abstract

The goal of this thesis work was to explore the interactions between a series of ruthenium complexes and the human telometric DNA sequence. Specifically, this work investigated the ability of [Ru(bpy)₂L]²⁺ and [Ru(phen)₂L]²⁺ complexes to act as G-quadruplex (GQ) stabilizing ligands (bpy = bipyridine, phen = phenanthroline, L = a polypyridyl derivative of dipyridophenazine (dppz)). [Ru(bpy)₂(dppz)]²⁺ and [Ru(phen)₂(dppz)]²⁺ are known to bind to GQ DNA, though not selectively and also to display molecular light switch activity upon interaction with DNA. The ruthenium complexes were studied in this work with several UV-visible and fluorescent techniques to determine the ability of each to stabilize GQs, selectively bind to GQ DNA over duplex DNA, and act as a molecular light switch. The binding affinity of the complexes to GQ DNA was determined by absorbance titration and the binding stoichiometry has been determined by Job plot. Several complexes have been identified as strongly stabilizing and reasonably selective for G-quadruplexes, including [Ru(bpy)₂(me₂allox)]²⁺. This work suggests that particular substitution patterns, such as modification of the C2 and C4 positions of the pteridinophenanthroline scaffold, are favorable for ruthenium complex-GQ interactions and that use of phenanthroline instead of the bipyridine ligands does not significantly impact the stabilization ability of the complex, suggesting that the interaction between Tel22 and the ruthenium complexes does not involve the phenanthroline or bipyridine ligands. Additionally, the fluorescent behavior of these complexes in the presence of GQ DNA was explored; none were found to be as strongly affected by the presence of GQ DNA as [Ru(bpy)₂(dppz)]²⁺, which shows a marked increase in fluorescent signal upon addition of DNA.

Included in

Chemistry Commons

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