Date of Award

2016

Document Type

Thesis

First Advisor

Dr. Michelle Hamm

Abstract

8-oxo-2’-deoxyguanosine (OdG) is a promutagenic DNA lesion that arises from exposure of 2’-deoxyguanosine (dG) to reactive oxygen species (ROS) like peroxides, hydroxy radicals, and superoxides. ROS are produced by environmental carcinogens, exposure to radiation, and even during cellular respiration. OdG lesions are very common in mammalian cells and can base pair to both 2’-deoxycytidine (dC) and 2’- deoxyadenosine (dA), the latter of which can result in dG → thymidine transversions. These mutations are believed to be responsible for the link between OdG and aging, and diseases like cancer, lupus, and arthritis. To gain insight into the preference for dCTP or dATP incorporation opposite OdG, and thereby the mutagenic potential of OdG, the large fragment of the A-family polymerase I from the bacterium Bacillus Stearothermophilus (BF) was investigated. Previous studies have suggested that active site clashing between Ile716 and either the C8-position of OdG during dCTP incorporation, or the C2-position of OdG during dATP incorporation can heavily influence the mutagenic potential of OdG. To further test the importance of these clashing interactions, the activities of dCTP and dATP incorporation opposite OdG and seven of its analogues were compared between wild type BF, Ile716Met BF, and Ile716Ala BF.

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