Overview
Antimicrobial resistance poses a mounting global health crisis, exemplified by Acinetobacter baumannii, a multidrug-resistant pathogen responsible for life-threatening hospital-acquired infections1. Designated by the WHO as a “critical priority” organism, A. baumannii urgently demands new therapeutic approaches as conventional antibiotics lose efficacy. Alternative approaches, such as targeting bacterial virulence rather than survival, aim to disarm the pathogen and reduce disease without promoting resistance or disrupting beneficial microbiota2.
About this opportunity
This project focuses on carboxy-terminal processing proteases (CTPs), a conserved family of serine proteases that regulate cell envelope integrity, signalling, and virulence across all domains of life. A. baumannii possesses an uncharacterised CTP linked to virulence3, but its molecular function remains unknown.
Research Aims
This PhD project will uncover the molecular and structural mechanisms by which the A. baumannii CTP contributes to bacterial virulence and biofilm formation. The student will:
- Define CTP function using molecular biology, proteomics, and infection models to identify physiological substrates and interaction partners.
- Determine the structural and mechanistic basis of CTP activity and substrate recognition through enzyme assays and X-ray crystallography.
- Develop peptide-based mechanistic inhibitors to probe substrate specificity and PDZ-domain regulation.
By integrating molecular microbiology, structural biology, advanced proteomics, and chemical biology this project will define enzyme function and substrate recognition, establishing a foundation for future antivirulence strategies against multidrug-resistant pathogens4.
Techniques & Training
The successful candidate will join an ambitious and supportive research group dedicated to uncovering the molecular mechanisms that underpin bacterial virulence and driving the development of anti-virulence strategies. This fully funded BBSRC project offers exceptional multidisciplinary training to develop a versatile and highly sought-after skillset, valued equally in academia and the biotechnology industry. You will be based in the Department of Clinical Infection, Microbiology & Immunology at the University of Liverpool, benefitting from access to outstanding research facilities, cutting-edge technical support, and a vibrant scientific community.
You will receive advanced, hands-on training in cutting-edge methodologies, including:
- Molecular biology: Core experience in cloning, recombinant protein expression, and purification, forming the foundation for downstream structural and functional studies.
- Structural biology: Application of X-ray crystallography to resolve the enzyme structures and ligand-bound states, advancing understanding of molecular mechanisms and guiding inhibitor design.
- Biochemistry & biophysics: Enzyme kinetics, site-directed mutagenesis, and biophysical interaction assays to dissect enzyme activity & regulation.
- Infection biology & Microbiology: Microbial assays and infection models to assess the physiological role of CTPs and their contribution to virulence.
- Proteomics & bioinformatics: Quantitative and targeted proteomic approaches to identify enzyme substrates and map protein–protein interaction networks.
- Peptide-based Inhibitor Development: Learn peptide synthesis and perform Alanine scanning to identify key residues for enzyme recognition, which will serve as mechanistic probes.
Further reading
1. Morris, F. C., Dexter, C., Kostoulias, X., Uddin, M. I. & Peleg, A. Y. The Mechanisms of Disease Caused by Acinetobacter baumannii. Frontiers in Microbiology 10, doi:10.3389/fmicb.2019.01601 (2019).
2. Lau, W. Y. V., Taylor, P. K., Brinkman, F. S. L. & Lee, A. H. Y. Pathogen-associated gene discovery workflows for novel antivirulence therapeutic development. EBioMedicine 88, 104429, doi:10.1016/j.ebiom.2022.104429 (2023).
3. Roy, R., You, R.-I., Lin, M.-D. & Lin, N.-T. Mutation of the Carboxy-Terminal Processing Protease in Acinetobacter baumannii Affects Motility, Leads to Loss of Membrane Integrity, and Reduces Virulence. Pathogens 9, 322, doi:10.3390/pathogens9050322 (2020).
4. Harding, C. J., Bischoff, M., Bergkessel, M. & Czekster, C. M. An anti-biofilm cyclic peptide targets a secreted aminopeptidase from P. aeruginosa. Nature Chemical Biology 19, 1158-1166, doi:10.1038/s41589-023-01373-8 (2023).