MS (Master of Science)
Date of Award
Committee Chair or Co-Chairs
Christopher Pritchett, Dhirendra Kumar
Iron is an essential element for most bacteria and is commonly acquired by siderophores, molecules secreted under iron restricted environment to bind ferric iron. Gram negative cells actively uptake these complexes via outer membrane-transport proteins such as FhuA in Escherichia coli. Structural analysis of receptors revealed a conserved β-barrel occluded by an N-terminal plug domain. The cell membrane TonB/ExbB/ExbD complex presumably supplies energy via interaction between the FhuA N-terminal TonB box and the C-terminal domain of TonB. In order to better understand the mechanism of action the FhuA mutant 104/149C, tethering the central β-strands 4 and 6 of the plug domain, was studied and showed severely reduced transport of radio-labeled ferrichrome. In the course of this study, this protein was HPLC purified for structural studies by crystallization and X-ray diffraction. In addition, protein interaction studies were performed with purified TonB-C terminal revealing no impact of the mutation on FhuA-TonB interactions.
Thesis - Open Access
Hagan, Ada K., "Characterization of FhuA 104/149C: a Double Cysteine FhuA Mutant with Normal Binding and Diminished Transport" (2012). Electronic Theses and Dissertations. Paper 1211. http://dc.etsu.edu/etd/1211
Copyright by the authors.