Title

Kinetic Studies of DNA Repair Enzyme ALKBH2

Author(s)

Michael R. Vittori, University of Rhode IslandFollow

Major

Pharm.D. (six years)

Advisor

Li, Deyu

Advisor Department

Biomedical and Pharmaceutical Sciences

Date

5-2017

Keywords

ALKBH2; enzyme kinetics; DNA repair; α-Ketoglutarate/Fe(II)-dependent dioxygenase; 1-methyladenine; 3-methylcytosine

Creative Commons License

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License.

Abstract

The genomes of living organisms are under constant bombardment from various sources, including chemical modification stemming from processes within the organisms themselves or from exogenous agents, and from radiation. These sources of genomic damage may induce structural changes in the genome’s most basic functional units, the nucleotides that comprise DNA. Damage to an organism’s DNA may result in the production of dysfunctional or nonfunctional proteins. Failure to repair such damage may result in the compounding of successive mutations within the organism’s genome, the pathogenesis of cancer and various genetic disorders in humans. To ensure their viability, organisms have developed unique defense mechanisms to combat genetic damage. Among these mechanisms are repair pathways that allow for the enzymatic correction of DNA lesions.

The human ALKBH2 protein (ABH2), an α‐ketoglutarate/Fe(II)-dependent dioxygenase, represents one such DNA repair enzyme. ABH2 represents a relatively novel and potentially fruitful subject for cancer research. ABH2 repairs alkylation damage in DNA through oxidative demethylation, displaying relative specificity for 1- methyladenine (m1A) and 3-methylcytosine (m3C) lesions. In addition to understanding how enzymatic repair systems correct certain DNA defects, it is important to thoroughly analyze the factors that influence the functioning of these catalytic protein complexes and the conditions that allow these systems to function optimally.

While several studies have already independently examined the factors associated with ABH2 enzyme functioning, a comprehensive analysis of these determinants has yet to be conducted. The purpose of this project is to determine how variations in several known factors required for the functioning of this enzyme affects its kinetics.

Completion of this project provided an in-depth analysis of the effect that changes in α-ketoglutarate, iron (II), ascorbic acid, pH, and temperature have on the correction of m1A, and m3C DNA lesions by the ABH2 repair enzyme. The results indicate that the optimal operating conditions for ABH2 may differ from what has been previously reported in the literature on this subject.