White Rose University Consortium logo
University of Leeds logo University of Sheffield logo York University logo

Structural and functional studies of proteins involved in spore formation in Bacillus subtilis

Hughes, Adam Michael (2018) Structural and functional studies of proteins involved in spore formation in Bacillus subtilis. PhD thesis, University of York.

[img] Text
Thesis final 2019 02 16 (1).docx - Examined Thesis (PDF)
Available under License Creative Commons Attribution-Noncommercial-No Derivative Works 2.0 UK: England & Wales.

Download (46Mb)


Bacillus subtilis and Clostridioides difficile are Gram-positive bacteria that may adapt to unfavourable conditions by forming a dormant spore. Sporulation involves an asymmetric cell division resulting in a larger mother cell and a smaller forespore. The forespore is later engulfed by the mother cell in a phagocytosis like process. Activation of the sporulation pathway is tightly regulated through complex sensor systems, crucial to which are peptides imported into the cell through peptide transport systems belonging to the ATP-binding cassette (ABC) family. Peptides have an important nutritional role as well as the signalling role and B. subtilis has three ABC peptide transporters with overlapping specificity, a dipeptide permease (Dpp) and two oligopeptide permeases (Opp and App). Here the crystal structures of the receptors for two of these transporters OppA and DppE are described revealing unexpectedly that DppE is a murein tripeptide binding protein whilst the OppA structure reveals a tetrapeptide bound whose average electron density closely resembles Ser-Asn-Ser-Ser. Crystallographic and peptide binding studies of OppA and AppA from C. difficile have led us to conclude that neither of these proteins is a receptor for peptide transport as previously reported. OppA is more likely to serve as a receptor for the uptake of nickel ions. Upon completion of engulfment, a channel is formed between mother cell and forespore at the heart of which is an intercellular interaction between SpoIIIAH and SpoIIQ that has been described structurally. The stoichiometry of this complex in vivo is unknown though models of rings containing 15-24 molecules have been proposed. Here experiments are described to fuse fluorescent reporters to SpoIIQ and SpoIIIAH in order to perform super resolution microscopy to determine the stoichiometry of the complex in live cells for the first time.

Item Type: Thesis (PhD)
Academic Units: The University of York > Chemistry (York)
Depositing User: Mr Adam Michael Hughes
Date Deposited: 15 Mar 2019 16:13
Last Modified: 15 Mar 2019 16:13
URI: http://etheses.whiterose.ac.uk/id/eprint/22976

You do not need to contact us to get a copy of this thesis. Please use the 'Download' link(s) above to get a copy.
You can contact us about this thesis. If you need to make a general enquiry, please see the Contact us page.

Actions (repository staff only: login required)