Electrochemical Detection of Benzo[a]Pyrene-Induced DNA Damage at TP53 Oligomers : Impact of 5'-Methyl Cytosine and Bioactivation on the Genotoxicity Process

ECU Author/Contributor (non-ECU co-authors, if there are any, appear on document)

Caitlin M. Trumbo (Creator)

Institution

East Carolina University (ECU )

Web Site: http://www.ecu.edu/lib/

Abstract: DNA houses the blueprint that dictates how an organism will develop. However, DNA features numerous reactive sites that can be attacked by chemicals and radiation, resulting in DNA damage and possibly mutations. Chemical products and other environmental toxins must be tested for genetic abnormalities due to exposure. Traditional DNA damage detection can be tedious, time-consuming, and cost prohibitive. Electrochemical methods to detect DNA damage offer remedies to these drawbacks. Simple and sensitive DNA hybridization sensors are widely used for DNA detection and studying biochemical processes at specific DNA sequences. An electrochemical DNA hybridization sensor designed to detect DNA damage at hotspot TP53 gene sequences resulting from bioactivated benzo[a]pyrene (BP) will be discussed. TP53 codes for the p53 protein, and mutations at the studied genetic sequence have been shown to be prevalent in many different cancers. Double stranded DNA 21-mers were absorbed on gold electrodes followed by adsorption and saturation with a heme enzyme model, myoglobin. Myoglobin was activated using hydrogen peroxide and exposed to solutions of BP, which allowed BP to be oxidized into reactive metabolites. DNA damage was detected voltametrically by charting changes in square wave voltammetric signals due to a redox-active di-viologen derivative that has been shown to bind to DNA in a structure-specific manner. Aspects of the sensor optimization process will be discussed including how BP stereochemistry and epigenetic factors influence the voltammetry, the impact of myoglobin non-specific adsorption on the electrode surface, and numerous control reactions designed to show that bioactivated reactive metabolites were detected at the DNA sequence. Overall, the incorporation of enzymes with a DNA hybridization interface has opened up new possibilities to utilize more biologically relevant enzymes, such as cytochrome P450s, to study of important metabolic related DNA damage processes at specific gene sequences.

Additional Information

Publication

Thesis

Language: English

Date: 2023

Subjects

Chemistry

Email this document to