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Structural and Functional Studies of the Antimicrobial Resistance Associated DedA Family

Scarsbrook, Hollie (2019) Structural and Functional Studies of the Antimicrobial Resistance Associated DedA Family. Master of Science by Research (MScRes) thesis, University of Kent,. (Access to this publication is currently restricted. You may be able to access a copy if URLs are provided) (KAR id:80522)

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Language: English

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Abstract

The advancement and adaptations of antimicrobial resistance mechanisms by bacteria causes a great health impact. To combat this,these mechanisms need to be understood. DedA are a family of proteins found within a variety of prokaryotes, shown to be possible drug sensitivity targets as although very little is known about these proteins, they are essential for cell viability and resistance to different antimicrobials. The potential of targeting these proteins and inhibiting the possible membrane transport mechanisms could possibly sensitise bacteria to a range of different antimicrobials, with particular reference to clinically relevant pathogens. This research studies the role of the DedA protein family with particular focus on the DedA protein; YqjA. This work utilised two key areas of analysis; topological analysis alongside biochemical and microbiological analysis to evaluate the role of the DedA protein YqjA in Escherichia coli (E. coli). Topological analysis of DedA protein family members was first analysed to form predictions for the structural features of YqjA. These predictions were then tested using substituted cysteine accessibility measurements to determine the position of introduced cysteines in relation to the membrane. Further work included sensitivity analysis of YqjA with single point mutations to different antimicrobials and stressors to determine the importance of specific amino acids for the functioning of the protein. This research identifies YqjA as a membrane protein with five transmembrane helices. Results from cysteine accessibility measurements highlighted the boundaries of each of the transmembrane helices as well as the boundaries between the helices. The work studying the function of different amino acids in YqjA highlighted two which are shown to be vital for the functioning of YqjA; YqjA R130 and YqjA R136. Other work using pH sensitivity tests determined which areas of the DedA member YghB is responsible for alkaline sensitivity. Overall, this research concludes that YqjA is a form of efflux protein located in the membrane and plays an important role in the export of different biocides. This has provided a greater insight into the possible role of DedA in E. coli.

Item Type: Thesis (Master of Science by Research (MScRes))
Thesis advisor: Mulligan, Christopher
Uncontrolled keywords: Biochemistry
Subjects: Q Science > QH Natural history
Divisions: Faculties > Sciences > School of Biosciences
SWORD Depositor: System Moodle
Depositing User: System Moodle
Date Deposited: 16 Mar 2020 17:10 UTC
Last Modified: 17 Mar 2020 08:46 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/80522 (The current URI for this page, for reference purposes)
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