Project Description 

Applications are invited for a research studentship leading to the award of a PhD degree, under the supervision of Professor A. William Rutherford, to investigate the relationship between membrane potential and Photosystem II function. The post is supported by a bursary and fees (at the UK student rate only) funded by the Leverhulme Trust. The studentship is for 36 months from October 2022 (or soon thereafter).

Photosynthesis changed the planet by fueling the biosphere and by producing the oxygen that energised the atmosphere. Photosystem II, the unique water-oxidising enzyme, uses light to split water into electrons, protons and molecular oxygen. The electrons generated by Photosystem II travel through the electron transfer chain to reduce CO₂ and to produce the fuels and building blocks of life. The electron transfer processes result in the movement of protons across the bioenergetic membrane, generating the proton motive force needed to make cellular energy.

The charge separation and stabilization steps in Photosystem II are altered by the electric field component of the proton motive force leading to the production of reactive oxygen species. In plants, this occurs during natural light conditions, limiting photosynthesis and productivity. In cyanobacteria this seems likely to occur but there is much more diversity in the key protein of Photosystem II. In this project, we shall study the effect of the electric field effect in a diverse range of cyanobacterial Photosystem II. These studies should explain how each variant form has dealt with the electric fields and thus provide a broader view on understanding how all types of Photosystem II are optimized to deal stresses under a range of environmental conditions.

The PhD student will investigate different forms of Photosystem II using a combination of physiological, biochemical, and biophysical methods on samples ranging from living cells to isolated enzymes. Using a newly developed spectroscopic method to measure the proton motive force in living cyanobacterial cells, methods will be developed to determine the magnitude and lifetime of electric field in the diverse variants of cyanobacterial Photosystem II. The aim is to determine how each Photosystem II variant has tuned its bioenergetics to its specific environment and how this impacts its resilience to the electric field.

The PhD student will receive training in microbiological techniques required for the cultivation of cyanobacteria, protein purification, and genetic engineering. In addition, the PhD student will learn a range of biophysical methods including spectroscopy applied to photosynthesis (in cells membranes and isolated enzymes), such as fluorescence, luminescence, and absorption spectroscopy, and structural methods.

Requirements and eligibility

The studentship provides 3 years of funding starting October 2022 (or soon thereafter).  Applicants should have a BSc honours degree (at least 2.1 or equivalent) in Biochemistry, Chemistry, Plant Biology or a related discipline. Applicants with a Masters degree (at Merit level or better) in addition to the BSc may be given preference. Ideally, the student will have a keen interest in photosynthetic electron transfer, protein structure/function, biophysics, and evolution. Interdisciplinarity may be given preference. Intellectual ability, enthusiasm and self-motivation are essential.

Funding provides full support for tuition fees for the three-year duration of the studentship, and an annual tax-free stipend of £17,609 per year.

How to apply: 

Please direct informal enquiries and requests for further information to both Professor A. William Rutherford (a.rutherford@imperial.ac.uk) and g.davis@imperial.ac.uk. Please email a single PDF file including: a brief cover letter describing your relevant interests and research experience, your c.v. and names and contact information of three referees to both a.rutherford@imperial.ac.uk and  g.davis@imperial.ac.uk. Applications will be considered as they are received, so early applications are encouraged.