Pushing electrons: How does Nature make it work in natural two-dimensional solar cells?

The Grantham Centre for Sustainable Futures focuses on advancing sustainability research and connecting it with the policy debate around how humans can live in a more sustainable way.
grantham.sheffield.ac.uk

We are recruiting Scholars who will combine outstanding intellect with a strong commitment to public engagement, leadership and action. These ambitious individuals will complete interdisciplinary PhD research projects to help solve the challenges of sustainability. They will be supported by the Centre through a unique training programme, designed to equip them with the skills to become policy advocates and leaders in sustainability matters.

Your application for this studentship should be accompanied by a CV and a 200 word supporting statement. Your statement should outline your aspirations and motivation for studying in the Grantham Centre, outlining any relevant experience.

Please select ’Standard PhD’ and the Department of Molecular Biology and Biotechnology. Fill in the title of your desired project and the name(s) of the supervisors’. The starting date of the PhD will be the start of the next academic year - 1 Oct 2017. The ’Funding stage’ on the form will be ’project studentship’.

The aim of the project is to characterise the molecular interactions at the single molecule level that govern the transient interface between the electron donor plastocyanin and photosystem I or cytochrome b6f, during photosynthesis in plants, algae and cyanobacteria. Specifically the project will investigate the timescales of the protein conformational changes and electron transfer reactions involved and their environmental dependence using nanoelectrical and nanomechanical atomic force microscopy and further characterize the exact molecular interactions via cross-linking and mass spectrometry.

Electron transfer reactions are the basis of photosynthesis and respiration, which power all life on Earth. In essence energy directly provided by the sun or from foodstuffs is used to move electrons along a chain of proteins; some of these proteins can move freely, shuttling back and forth carrying their cargo of electrons to and from other proteins that are held in position within a thin sheet of membrane. The mystery is how a freely-moving protein finds its way to a particular membrane-attached protein, how it docks at the membrane surface, releases its electron and then manages to undock, all in a few milliseconds. Yet without hundreds of these electron transfer reactions happening every second, life on Earth could not be sustained. Somehow these pairs of proteins balance two conflicting requirements: they have to come together quickly and specifically to transfer electrons, yet they also have to be able to separate rapidly afterwards. So whatever forces brought the proteins together in the first place can be switched into reverse – how is this possible? What is this switch? Finding this out is the purpose of the proposed research, and it has important implications for all energy-yielding electron transfers on Earth.

Key words:
Photosynthesis, electron transfer, atomic force microscopy, mass spectrometry, membrane biochemistry