Recognition and repair of DNA damage by bacterial adenine glycosylases

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Publication Type thesis
School or College College of Science
Department Chemistry
Author Richards, Jody Lyn
Title Recognition and repair of DNA damage by bacterial adenine glycosylases
Date 2008-05
Description E. coli MutY is a base excision repair (BER) glycosylase that excises adenine mispaired opposite 7,8-dihydro-8-oxo-2'-deoxyguanine. MutY has helix-hairpin-helix and Gly/Pro-Asp structural motifs characteristic of the BER glycosylase superfamily. In addition, it has an iron-sulfur cluster that is critical for substrate binding and catalytic activity. In the absence of DNA this cluster is not redox active; however, in the presence of DNA, its redox potential shifts dramatically. Here, the effects of DNA binding on the 4Fe-4S cluster of MutY are analyzed by two spectroscopic methods: Electron Paramagnetic Resonance (EPR) and X-ray Absorption Spectroscopy (XAS). By EPR, no difference in levels of cluster oxidation is observed when MutY is bound to a DNA oligonucleotide duplex containing either a G:C or G:THF central base pair, despite much tighter binding of the latter. EPR also shows that oxidation of the cluster is affected by the identity of the oxidant presented. XAS on MutY bound to DNA shows an increase in covalency of the Fe-S bonds relative to the cluster in the absence of DNA. MutY from a thermophilic bacterium B. stearothermophilus (BsMY) was expressed, purified, and characterized kinetically. Its glycosylase activity showed both temperature and salt dependence. In addition, BsMY discriminated more stringently than E. coli MutY between OG:A and G:A substrates.
Type Text
Publisher University of Utah
Subject DNA repair; Adenine
Dissertation Institution University of Utah
Dissertation Name MS
Language eng
Relation is Version of Digital reproduction of "Recognition and repair of DNA damage by bacterial adenine glycosylases " J. Willard Marriott Library Special Collections, QH9.7 2008 .R53
Rights Management © Adenine Richards To comply with copyright, the file for this work may be restricted to The University of Utah campus libraries pending author permission.
Format Medium application/pdf
Format Extent 8,880,532 bytes
Identifier us-etd2,91685
Source Original: University of Utah J. Willard Marriott Library Special Collections
ARK ark:/87278/s6nz8p45
Setname ir_etd
Date Created 2012-04-23
Date Modified 2021-05-06
ID 192606
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