Molecular mechanisms underpinning A. baumannii virulence

Antimicrobial resistance (AMR) is a major public health threat. Acinetobacter baumannii, is the leading cause of nosocomial infections worldwide, where its high resistance to antibiotic treatments and ability to cause lethal infections, has led to its categorisation as a “critical priority” pathogen by the WHO¹. New therapeutic approaches, beyond traditional antibiotics, are urgently needed to address the issue. A compelling approach is to target bacterial virulence factors; specifically reducing pathogen fitness and its ability to cause disease, without exerting a high selection pressure for resistance or affecting commensal bacteria. However, a key limitation in combatting A. baumannii this way, is the current lack of understanding concerning the molecular mechanisms underpinning virulence.

A. baumannii relies on several virulence factors and is especially skilled at adapting to hostile environments and meeting its nutritional needs, particularly scavenging and utilising essential metals (e.g. iron, zinc, manganese). Metals must be obtained directly from the environment; placing them at the interface between host and pathogens during infections². Metal homeostasis and delivery of correct metals to metalloproteins is a crucial process, yet it remains poorly understood. A. baumannii possesses a COG0523 metallochaperone, ZigA, which is proposed to traffic zinc under metal limited conditions^3,4. Uncovering the structure and function of ZigA will shed light on its important role during infections and may unlock new therapeutic avenues.

Objectives

·      Understand the underpinning mechanisms of ZigA, revealing its structure and function, metal preference/selection and regulatory features through structural and biochemical techniques.

·      Identify interacting proteins using proteomics methods, unravel its interactome and establish how metals are successfully transferred.

·      Determine the functional role of ZigA and its contribution to virulence, by evaluating KO mutants in clinically relevant strains using in vitro and in vivo infection models.

Experimental approaches

The student will join an ambitious group seeking to uncover the molecular mechanisms underpinning virulence. This project is highly inter-disciplinary and offers broad training in the fields of structural biology, biochemistry and infection biology. Outstanding training and support will be offered to develop a wide range of skills and techniques. The opportunity to explore and untangle the function of these metallochaperones from a highly problematic bacterial pathogen, is ideal for a keen biochemist.

·      Molecular biology techniques for cloning, expression & purification of recombinant proteins.

·      X-ray crystallography, to determine enzyme structure and substrate complexes.

·      Biophysical & biochemical assays (e.g. enzyme kinetic assays) to determine enzyme function and activity.

·      Proteomics (mass spec), to ID interacting proteins.

·      Microbiology skills, manipulate bacterial genomes (KO mutations) and assays for viability and growth.

·      Clinically relevant in vitro & in vivo models of infection, to determine the physiological role of metallochaperones in A. baumannii and understand how they contribute to virulence. 

Applicants must have obtained, or expect to obtain, a UK honours degree at 2.1 or above (or equivalent for non-UK qualifications), in a relevant discipline.

Informal enquiries can be made via a covering letter and 2-page CV to Christopher.Harding@liverpool.ac.uk. If deemed suitable candidates would then be asked to complete a formal application and an interview will be required. The application deadline may change if suitable candidate has been found, prior to the original listed date.