Understanding the structure and function of a new bacterial iron store

Bacteria do not possess the membrane-bounded organelles, such as mitochondria and chloroplasts, that are characteristic of eukaryotes. However, some bacteria have cellular compartments that function like organelles, but are made entirely from proteins. These bacterial compartments allow the cell to partition specific metabolic pathways that produce reactive intermediates and toxic products. The simplest of these compartments are single-enzyme systems with a protected interior, such as the ferritin iron-stores, which are found in all forms of life. Encapsulin nanocompartments are found in bacteria and archaea and consist of a virus capsid-like shell, which sequesters specific enzymes to store iron, or to protect the cell from oxidative damage. The most complex bacterial compartments are the carboxysomes and bacterial microcompartments, which have complex multi-protein shells and contain multi-enzyme pathways.

This project will focus on a newly identified encapsulin nanocompartment found within bacteria of the Firmicutes phylum, which includes industrially important Bacillus species, such as Bacillus subtilis; and a number of key pathogens, including the food-borne Bacillus cereus, Clostridium difficile, and Clostridium perfringens. This new encapsulin nanocompartment acts as a bacterial iron storage system and its cargo enzyme, which is thought to be responsible for iron-oxidation, represents a new class of proteins.

Specific goals and objectives:
• In this project you will produce encapsulin nanocompartments both in the native host, Bacillus methanolicus, and in Escherichia coli, for structural and functional analyses to understand how iron is stored within the compartment.
• You will use cutting edge structural biology and imaging techniques, including electron and fluorescence microscopy, to analyse the molecular structure of the nanocompartment.
• You will also analyse the physical properties of the assemblies using atomic force microscopy. Metal binding by these proteins will be analysed by biophysical techniques, such as Inductively Coupled Plasma Mass Spectrometry and Electron Paramagnetic Spectroscopy.
• You will develop B. methanolicus as a model organism to study its physiology. This will involve the design and assembly of modular vector systems and implementation of gene-knockout and replacement methods.
• The data produced in these structural and biochemical studies will be complemented with experiments performed on the B. methanolicus strain to understand how the encapsulin is able to store iron in the cells and to determine if it can protect the cell from environmental stress and oxidative damage.

Supervision
This is a joint project between Newcastle and Liverpool Universities: you will be based in the Laboratory of Dr Marles-Wright (www.marles-wright-lab.org) in the School of Natural and environmental Sciences, and work closely with co-supervisor Dr Kevin Waldron in the Faculty of Medical Sciences. You will have the opportunity to spend up to 6 months with our collaborator in Liverpool, Dr Luning Liu (www.luningliu.org).

Training
Training will be given in basic microbiology, molecular biology techniques, and recombinant protein expression and purification. The project will make use of advanced biophysical and structural techniques, including cryo-electron microscopy and single-particle analysis to characterise the assembly of compartments in cells and in solution. This project would suit a candidate with a degree in microbiology, biochemistry, or chemistry with an interest in developing skills in structural biology, and biophysics. There will be opportunities to work with our international collaborators and develop a strong scientific network.

For further information see the website: https://www.ncl.ac.uk/nes/

To apply
Please complete the online application form and attach a full CV and covering letter. Informal enquiries may be made to [Email Address Removed]