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Kate_Butler_Final_complete_thesis.pdf (1.7 MB)
ETD Abstract Container
Abstract Header
Functional complementation of
ΔexbD E. coli
by homologous
exbD
genes
Author Info
Butler, Kate Ann
Permalink:
http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1377012630
Abstract Details
Year and Degree
2013, Master of Science (MS), Bowling Green State University, Biological Sciences.
Abstract
The TonB system energizes the high affinity transport of ferric siderophores in gram negative bacteria. Within this system, there are three main proteins: TonB, ExbB, and ExbD. This study was focused on the role of the ExbD protein in the system. The hypothesis that ExbD is responsible for recycling TonB was examined by a strategy in which homologous
exbD
genes were used to complement an
E. coli exbD
strain. The more closely related species'
exbD
gene conferred functionality better than
exbD
genes from more distantly related species. The
exbD
homologues from
Serratia liquefaciens, Yersinia entercolitica, Proteus mirabilis
, and
Vibrio parahaemolyticus
were tested. The ability of ExbD homologues to support TonB function was evaluated by performing sensitivity assays against colicins and bacteriophage in
E. coli
with the
exbD
gene from each of the different species. I found that
exbD
genes from all species except for the
Vibrio
rendered
E. coli
sensitive to these agents. A more precise iron transport assay was performed and it showed similar results to the killing assays. ExbD from
Serratia, Proteus
, and
Yersinia
, were each able to to support the TonB-dependent transport of ferric siderophore across the outer membrane, albeit less with less efficiency in the case of
Yersinia
. As with the killing assays, here the
Vibrio exbD
genes were again unable to support a TonB-dependent process. However, studies of TonB half life indicated that, while unable to support TonB activity, the ExbDs from Vibrio still conferred stability to TonB in
E. coli
, suggesting that they did assemble into the proton translocating complex and did associate with TonB. This suggests that ExbD may play a role in proper positioning of TonB. These results indicate that ExbD plays a more active role within the TonB system than originally contemplated.
Committee
Ray A. Larsen (Advisor)
Vipa Phuntumart (Committee Member)
Paul Morris (Committee Member)
Subject Headings
Biology
;
Microbiology
;
Molecular Biology
Keywords
ExbD
;
TonB system
;
E coli
;
gram negative bacteria
Recommended Citations
Refworks
EndNote
RIS
Mendeley
Citations
Butler, K. A. (2013).
Functional complementation of
ΔexbD E. coli
by homologous
exbD
genes
[Master's thesis, Bowling Green State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1377012630
APA Style (7th edition)
Butler, Kate.
Functional complementation of
ΔexbD E. coli
by homologous
exbD
genes.
2013. Bowling Green State University, Master's thesis.
OhioLINK Electronic Theses and Dissertations Center
, http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1377012630.
MLA Style (8th edition)
Butler, Kate. "Functional complementation of
ΔexbD E. coli
by homologous
exbD
genes." Master's thesis, Bowling Green State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1377012630
Chicago Manual of Style (17th edition)
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Document number:
bgsu1377012630
Download Count:
679
Copyright Info
© 2013, all rights reserved.
This open access ETD is published by Bowling Green State University and OhioLINK.