Understanding the structure and function of a new bacterial iron store

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This project will use structural biology techniques, coupled with biochemical and biophysical analyses to understand the structure of a new class of bacterial iron store.Many strains of bacteria and archaea possess protein-bounded metabolic compartments, which form regular semi-permeable shells to protect the cell from pathways that produce reactive oxygen species, or toxic intermediate chemicals. These compartments range in complexity from the simple ferritin nanocages; to encapsulins, which are built from a single shell protein with a single captive enzyme; to the bacterial microcompartments, with shells made up of a number of different proteins and multi-enzyme pathways sequestered inside. Recently, a number of new classes of bacterial iron storage systems have been identified across many bacterial and archaeal phyla. These new bacterial iron storage systems consist of new classes of iron-oxidising proteins that reside within virus-like encapsulin nanocages. They appear to function as bulk stores for bioavailable iron phosphate minerals. In this project, the student will investigate the structure and function of examples of these new iron storage systems from selected bacterial and archaeal species. Using cutting edge X-ray facilities in the Newcastle Structural Biology Laboratory and new BBSRC-funded cryo-EM facilities in the Electron Microscopy Research Service at Newcastle University, the detailed atomic structures of these new iron storage systems will be determined. Biochemical and metal-binding analyses will be performed on purified proteins to determine how they function as iron stores. In the course of the project tools for the production of recombinant encapsulins with various protein cargoes will be produced. The biochemical and biophysical properties of these proteins will be analysed using spectrophotometric and mass spectrometry methods with the Clarke Group at the University of Edinburgh. The influence of iron-mineralisation within the encapsulin shell on the physical properties of these nanocompartments will be assessed by Atomic Force Microscopy in collaboration with Dr Luning Liu at the University of Liverpool.