This dissertation describes the crystal structures of two distinct metal-binding proteins: Escherichia coli Iron-sulfur cluster protein A and the carboxyltransferase subunit of the acetyl-coA carboxylase enzymes from Staphylococcus aureus and Escherichia coli.
Iron-sulfur cluster protein A (IscA) belongs to an ancient family of proteins responsible for iron-sulfur cluster assembly in essential metabolic pathways preserved throughout evolution. The crystal structure of Escherichia coli IscA reveals a novel fold in which mixed beta-sheets form a compact alpha-beta sandwich domain. In contrast to the highly mobile secondary structural elements within the bacterial Fe-S scaffold protein IscU, a protein which is thought to have a similar function, the great majority of the amino acids which are conserved in IscA homologues are located in elements which constitute a well-ordered fold. However, the 10-residue C-terminal tail segment which contains two invariant cysteines critical for the Fe-S binding function of IscA is not ordered. In addition, the crystal packing reveals a helical assembly which is constructed from two possible tetrameric oligomers of IscA.
The rates of severe, multi-drug resistant bacterial infections, including those caused by pathogens previously confined to the hospital setting, have increased dramatically in both hospital and community populations. Acetyl-coA carboxylase is a central metabolic enzyme that catalyzes the committed step in fatty acid biosynthesis: biotin-dependent conversion of acetyl-coA to malonyl-coA. This work presents the structures of the bacterial carboxyltransferase subunits from two prevalent nosocomial pathogens, Staphylococcus aureus and Escherichia coli. Both structures reveal a small, independent zinc-binding domain that appears to shield the active site during the catalytic process. The zinc domain of bacterial carboxyltransferase, which lacks a complement in the primary sequence or structure of the eukaryotic homologue, is a feature that yields promise for the structure-based design and development of new, selective antimicrobial classes.
| Identifer | oai:union.ndltd.org:VANDERBILT/oai:VANDERBILTETD:etd-01222006-213113 |
| Date | 27 January 2006 |
| Creators | Bilder, Patrick Wallace |
| Contributors | Dr. Richard Armstrong, Dr. David Ong, Dr. Fred Guengerich, Dr. Gerald Stubbs, Dr. Marcia Newcomer |
| 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-01222006-213113/ |
| Rights | unrestricted, 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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