The Library
Structural and functional characterization of a bile acid sodium symporter from Neisseria meningitidis
Tools
Becker, Patrick (2021) Structural and functional characterization of a bile acid sodium symporter from Neisseria meningitidis. PhD thesis, University of Warwick.
|
PDF
WRAP_Theses_Becker_2021.pdf - Submitted Version - Requires a PDF viewer. Download (34Mb) | Preview |
Official URL: http://webcat.warwick.ac.uk/record=b3759395
Abstract
The apical sodium-dependent bile acid transporter from Neisseria meningitidis (ASBTNM) shares 26% identity and 54% similarity to human ASBT which plays a key role in the reabsorption of bile acids in the terminal ileum and has gained interest as a pharmaceutical target. The structure of ASBTNM was solved at 2:2_A (Hu et al. 2011) and can be used as a model to understand the transport mechanism of the human protein. Nevertheless, more structural and functional information are needed to elucidate the transport mechanism. In this thesis, three different structures of the wild type and an E260A mutant are discussed which show different sodium-binding states in the inward-facing conformation. The structures showed that taurocholate-release and sodium-release do not induce major conformational changes in the protein. Furthermore, the E260A structure showed some differences in the positioning of the core and panel domain to each other indicating the beginning of a rotation movement. TM6 was shown to be able to unwind at the extracellular part and contains a potential hinge region allowing an outward movement in the outward-facing conformation to open the substrate binding site. Two liposome-based transport assays were performed. Both showed a time-dependent uptake of taurocholate by ASBTNM. Sodium depletion did not abolish taurocholate transport which could indicate that the transporter does not work in a completely stringent sodium-dependent manner. Unfortunately, both assays have not been successful when the transport activity of difffferent ASBTNM mutants was investigated. A wild type ASBTNM structure with pantoate bound was solved at 2:6_A. Pantoate was shown to bind to the wild type protein with an estimated KD of 124 _M. The structural information from this thesis will help to further understand the transport mechanism of hASBT as it adds further elucidated conformations (inward-facing) to a complete transport cycle. The identification of the pantoate binding site in ASBTNM can help to understand the ligand recognition of the plant BASS transporters which share homology to ASBTNM.
Item Type: | Thesis (PhD) | ||||
---|---|---|---|---|---|
Subjects: | Q Science > QH Natural history > QH301 Biology Q Science > QP Physiology Q Science > QR Microbiology |
||||
Library of Congress Subject Headings (LCSH): | Bile acids -- Transport properties, Neisseria meningitidis, Sodium cotransport systems, Biological Transport, Membrane proteins | ||||
Official Date: | May 2021 | ||||
Dates: |
|
||||
Institution: | University of Warwick | ||||
Theses Department: | School of Life Sciences | ||||
Thesis Type: | PhD | ||||
Publication Status: | Unpublished | ||||
Supervisor(s)/Advisor: | Cameron, Alexander | ||||
Sponsors: | National Institute for Health Research (Great Britain) | ||||
Format of File: | |||||
Extent: | xvii, 173 leaves : illustrations | ||||
Language: | eng |
Request changes or add full text files to a record
Repository staff actions (login required)
View Item |