We use cookies to ensure that we give you the best experience on our website. By continuing to browse this repository, you give consent for essential cookies to be used. You can read more about our Privacy and Cookie Policy.

Durham e-Theses
You are in:

Investigating antimicrobial resistance mechanisms in
Neisseria gonorrhoeae using
peptide probes

BURTON, MATTHEW,FRANCIS (2009) Investigating antimicrobial resistance mechanisms in
Neisseria gonorrhoeae using
peptide probes.
Doctoral thesis, Durham University.



The continuing evolution of antibiotic resistance strains of Neisseria gonorrhoeae coupled with the paucity of new antimicrobial agents makes the treatment of gonococcal infections challenging. A major cause of resistance is the expression of a multidrug efflux pump termed MtrCDE, which exports a wide range of antimicrobial agents. Efflux pumps are membrane-bound systems and consequently challenging to study and target with drugs. The transcriptional regulator (MtrR) of the efflux pump, however, is a soluble protein and therefore more amenable to study and drug target validation investigations. This thesis serves to investigate the hypothesis that substrates for the MtrCDE efflux pump are also ligands for the regulator MtrR.

Isothermal titration calorimetry (ITC) was used to show that MtrR binds commercial antibiotics and antimicrobial peptides. -lactam antibiotics not only bind MtrR but are hydrolysed by the multidrug protein. Evidence for this novel enzymatic activity is provided by ITC, mass spectrometric and microbiological techniques.

A series of peptides derived from LL-37 were synthesised and screened for binding to MtrR. A key region of LL-37 with a higher affinity to MtrR than the natural product was then identified. The peptide binding site in MtrR was elucidated via a photoactivated peptide binding study. Electrophoresis mobility shift assays indicated that the peptides do not induce derepression of the genes controlled by MtrR, although the peptide derivatives of LL-37 were shown to be substrates for the MtrCDE efflux pump.

Item Type:Thesis (Doctoral)
Award:Doctor of Philosophy
Keywords:Antibiotic; resistance; Neisseria gonorrhoeae; MtrR; LL-37; peptide
Faculty and Department:Faculty of Science > Chemistry, Department of
Thesis Date:2009
Copyright:Copyright of this thesis is held by the author
Deposited On:29 Mar 2010 16:01

Social bookmarking: del.icio.usConnoteaBibSonomyCiteULikeFacebookTwitter