Drug target deconvolution in Wolbachia: a chemical proteomic route to discovering novel antibacterial targets

Background:
Lymphatic filariasis and onchocerciasis are tropical parasitic worm infectious diseases that are leading causes of global disability. The control and elimination of these diseases is hampered by the lack of safe and effective drugs. Targeting an essential bacterial symbiont of the worm (Wolbachia) leads to death of the adult worms: an important advance over currently used treatments. The Anti-Wolbachia (A·WOL) consortium has developed a Phase I candidate molecule (Tylosin A (TylAMac™)) and independent pre-clinical candidate (AWZ1066) that kill Wolbachia, but the specific targets within the bacteria are unknown. This project will utilise chemical biology techniques to identify the protein targets of these anti-Wolbachia molecules.

Aims:
This project will identify the protein targets of candidate molecules TylAMac™ and AWZ1066 in Wolbachia pipientis with the intention of validating this approach for the discovery of novel bacterial targets and tools to monitor resistance. Photoaffinity probe molecules will be designed and prioritised for synthesis through modelling of existing compound (>200) data sets to ensure good biological activity, using routes already established for these chemotypes. Following optimisation of the probes and confirmation of activity against Wolbachia, an affinity purification approach, following incubation with lysates will be performed in order to assess specific and non-specific binding and thus determine the proteins of interest. These enriched proteins will be identified and semi-quantified by a fully automated LC-MS/MS protocol complemented by bioinformatics, validating for the first time, this target identification approach in Wolbachia. Initial modelling of TylAMacTM will be performed against the known bacterial ribosomal targets of the broader macrolide class with a view to homology based studies using a Wolbachia model post target identification.

This multidisciplinary project brings together expertise in medicinal chemistry (Nixon, O’Neill, Hong) and structure-based drug design (Berry). The longstanding highly productive relationship with the Liverpool School of Tropical Medicine (LSTM) provides the biological input. The PhD student will be engaged in both synthesis and modelling primarily, but will spend short periods of time in LSTM gaining experience and understanding of the systems and data.

The successful candidate will benefit from a diverse and enriching environment and will be trained in a number of key core skills: computational chemistry, synthetic chemistry, proteomic based chemical biology techniques and analytical chemistry. These skills will provide the student with a competitive advantage for future professional jobs in academia or industry.
Candidates are expected to hold (or be about to obtain) a minimum upper second class honours degree (or equivalent) in Biochemistry or Organic Chemistry.