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What Mediates Cor:FhuA Interactions?

Brown, Alec, Brown
http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1533827975226664

Abstract Details

2018, Master of Science (MS), Bowling Green State University, Biological Sciences.
TonB-dependent transporters (TBDT) are a class of outer membrane proteins found in gram-negative bacteria. These proteins serve as transporters for a variety of specific ligands and as receptors exploited by bacteriophage and toxins. The binding of a cognate ligand on the external surface of the TBDT induces a conformational change on the inner-facing (periplasmic) surface of the protein. The change in response to ligand occupancy renders a region in the extreme amino terminus (termed the “TonB-box”) accessible to the cytoplasmic membrane protein TonB. The interaction of TonB with this, and potentially other periplasmically-exposed regions facilitates energy transfer from TonB to the TBDT, driving a conformational change that provides for the vectoral transfer of the bound ligand from the outer to the inner surface, with subsequent ligand release into the periplasmic space. The mechanism of energy transfer and the subsequent transport event remains unclear. The gram-negative bacterium Escherichia coli contains eight distinct TBDTs including the ferric hydroxamate transporter FhuA. In addition to providing for the uptake of Fe(III)- ferrochrome conjugates, FhuA is recognized as a receptor by phi80, T1 and T5 bacteriophage. As such, these viruses present potential tools for addressing the fundamental mechanism of active transport and the coupling of TonB to that process. Beyond using FhuA as a receptor for infection, phi80 and T1 also encode a small putative lipoprotein (termed “Cor”) that is trafficked to the inner surface of the outer membrane, where it renders FhuA unable to transport bound ligand. Expression of cloned phi80 cor gene in E. coli, is sufficient to curtail FhuA-mediated transport of both TonB-dependent and –independent ligands. In this thesis, phylogenetic comparisons between phi80 and cor gene homologues of other bacteriophage are used to predict potential amino acids essential for Cor protein function, and site-directed mutagenesis to engineer mutant Cor derivatives to test those predictions.
Ray Larsen, Dr. (Advisor)
Vipaporn Phunutmart, Dr. (Committee Member)
Jill Zeilstra-Ryalls, Dr. (Committee Member)
67 p.
Biology
Cor; FhuA; TonB

Recommended Citations

Citations

  • Brown, Brown, A. (2018). What Mediates Cor:FhuA Interactions? [Master's thesis, Bowling Green State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1533827975226664

    APA Style (7th edition)

  • Brown, Brown, Alec. What Mediates Cor:FhuA Interactions? . 2018. Bowling Green State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1533827975226664.

    MLA Style (8th edition)

  • Brown, Brown, Alec. "What Mediates Cor:FhuA Interactions? ." Master's thesis, Bowling Green State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1533827975226664

    Chicago Manual of Style (17th edition)

bgsu1533827975226664
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This open access ETD is published by Bowling Green State University and OhioLINK.