Work presented in this dissertation details structural and biochemical characterization of three yeast alkylpurine DNA glycosylases Mag1 and Mag2 from S. pombe and Mag from S. cerevisiae. I determined high resolution crystal structures all three enzymes and used the structures to initiate a deeper understanding of the sources of substrate specificity and catalytic competence in DNA glycosylases. My study of Mag1 and Mag provided novel evidence that protein-DNA interactions away from the active site can modulate the specificity of DNA glycosylases and a single substitution in the minor-groove interrogating loop is sufficient to alter the preference of one alkylpurine glycosylase for εA to that of a homologous enzyme. The crystal structure of Mag2 along with biochemical and phylogenetic analysis of the Mag genes in related fungal species studies showed that spMag2 cannot form a catalytically competent complex with DNA due to differences in the minor-groove interrogating loop and overall electrostatic surface potential compared to other alkylpurine glycosylases and may have evolved to perform a separate function.
| Identifer | oai:union.ndltd.org:VANDERBILT/oai:VANDERBILTETD:etd-02222013-142422 |
| Date | 04 March 2013 |
| Creators | Adhikary, Suraj |
| Contributors | Brandt Eichman, Charles K. Singleton, Neil Osheroff, Katherine L. Friedman |
| Publisher | VANDERBILT |
| Source Sets | Vanderbilt University Theses |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.vanderbilt.edu/available/etd-02222013-142422/ |
| Rights | restrictone, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Vanderbilt University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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