johnsonmDr Matt Johnson

Room: E6a
0114 222 4418
matt.johnson@sheffield.ac.uk

General

Career History

  • 2015 - present: Lecturer, Dept. of Molecular Biology and Biotechnology, The University of Sheffield
  • 2012 - 2015: Leverhulme Research Fellow, Dept. of Molecular Biology and Biotechnology, The University of Sheffield
  • 2011 - 2012: Project Sunshine Research Fellow, Dept. of Molecular Biology and Biotechnology, The University of Sheffield.
  • 2010 - 2011: EPSRC Postdoctoral Research Associate, Queen Mary University of London.
  • 2007 - 2010: BBSRC Postdoctoral Research Associate, Queen Mary University of London.
  • 2003 - 2007: PhD ‘The role of the xanthophyll cycle in photoproection in Arabidopsis thaliana’, Dept. of Molecular Biology and Biotechnology, The University of Sheffield.

Honours and Distinctions

  • 2016: Society for Experimental Biology President’s Medal in Plant Science
  • 2018: Biochemical Society Colworth Medal

Research Keywords

Plant science, photosynthesis, thylakoid membranes, high-resolution microscopy

Research

My research is focused on the role of thylakoid membrane organisation in photosynthesis, the process that uses solar energy to transform water and carbon dioxide into the energy we consume and the oxygen we breathe. The enzymatic fixation of carbon dioxide into carbohydrate in the chloroplast stroma requires energy in the form of ATP and reducing power in the form of NADPH, which are provided by photosynthetic electron transport in the thylakoid membrane. The thylakoid membrane houses several major pigment-protein complexes involved electron transport including photosystem II, the water splitting enzyme, cytochrome b6f, photosystem I and ATP synthase. The efficiency of photosynthesis depends upon the rate of excitation energy transfer, the diffusion of electron carriers and the effectiveness of regulatory and repair processes, which in turn depend upon the spatial organisation of the pigment-protein complexes in the membrane.

I use a multidisciplinary approach combining high resolution imaging techniques such as atomic force microscopy, affinity-mapping AFM and stochastic super-optical microscopy (STORM/ PALM) with membrane biochemistry to elucidate how these complexes are spatially organised within the membrane. These state-of-the-art single molecule techniques allow me to gently image the membranes in their natural liquid environment thus preserving the native organisation of the pigment-protein complexes within. Armed with the complete picture of how the protein complexes of photosynthesis fit together in the membrane we can identify new genetic targets for improving the efficiency of photosynthesis for increased food and biofuel production. Understanding natural photosynthetic membrane organisation will also allow us to better imitate nature and so improve the design of artificial solar cells and carbon capture devices to provide green energy and a low carbon future for the planet.

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Teaching

Level 2 Modules

Level 1 Modules

PhD Opportunities

I welcome applications from prospective home / EU PhD students for two fully funded PhD studentships: see details below.

You can apply for a PhD position in MBB here.

Contact me at matt.johnson@sheffield.ac.uk for further information.


Structural role of photosystem II supercomplexes in thylakoid membrane stacking - FULLY FUNDED

Life on earth depends on photosynthesis, the source of all of our food, oxygen and most of our energy. The early steps of photosynthesis involve trapping of solar energy by electron transfer reactions in the photosynthetic membrane. Our recent studies have revealed an unexpected role for the membrane protein photosystem II (PSII) supercomplexes in mediating the stacking of chloroplast thylakoid membranes. Membrane stacking instigates the spatial segregation of the slow excitation energy trap PSII from the faster trap photosystem I (PSI), and promotes energy transfer among PSII units both of which are crucial for the efficiency of photosynthesis. For the first time we have biochemically-isolated a unique stacked form of the PSII supercomplex which will allow us to investigate this critical feature of the process. This project will make use of the latest advances in structural and functional microscopies to characterise this PSII supercomplex and understand how and why thylakoid membranes stack in molecular detail.

The PhD will offer the candidate a broad interdisciplinary training in modern biochemistry purification techniques, mass spectrometry and fluorescence and absorption spectroscopy, with the opportunity to interact with biologists, biophysicists and chemical engineers during the course of their project.

Relevant publications:

Ruban AV, Johnson MP (2015) Towards visualization of the dynamics of the plant photosynthetic membrane. Nature Plants. In Press.

Johnson MP, Vasilev C, Olsen J, Hunter CN (2014) Nanodomains of cytochrome b6f and photsosytem II in spinach grana thylakoid membranes. Plant Cell. 26, 3051-3061

This studentship is funnded by the BBSRC White Rose DTP.

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

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.

This four-year studentship will be fully funded at Home/EU or international rates. Support for travel and consumables (RTSG) will also be made available at standard rate of £2,627 per annum, with an additional one-off allowance of £1,000 for a computer in the first year. Students will receive an annual stipend of £17,336. The stsudent will be part of the Grantham Centre for Sustainable Futures.

Applying: Apply online here. Please select ‘standard PhD’ not DTC option, and ‘Department of Molecular Biology and Biotechnology’. 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. Deadline for application is Feb 23 2017.









































Publications

Journal articles

Conference proceedings papers

  • Adams PG, Vasilev C, Collins AM, Montano GA, Hunter CN & Johnson MP (2016) Redesigning Photosynthetic Membranes: Development of Bio-Inspired Photonic Nanomaterials. BIOPHYSICAL JOURNAL, Vol. 110(3) (pp 19A-19A)