| Our primary interest is in the first part of photosynthesis - the capture and conversion of light energy by Photosystem II that leads to the oxidation of water. In evolution, this process has been the main biological energy input to the living world and the only one responsible for generating all atmospheric oxygen (O2).
We also study the light-induced inhibition of Photosystem II, how plants protect themselves in excess light, the dynamic structure/function relationships of the photosynthetic apparatus with particular reference to order/disorder, and the supramolecular organization of various protein complexes under dark and varying light conditions.
Our main goal is to contribute to the understanding of the basic principles in the photosynthetic process, so that they can be applied to optimize both natural photosynthesis and bio-inspired artificial systems. Specific goals include the use of available genetic information to engineer artificial proteins that are modeled on Photosystem II and designed to convert light energy into useful chemical or electrical energy, and biomimetic systems that produce hydrogen (H2) through the photo-decomposition of water (Molecular Biofuels).
Current Research
The appearance of photochemical reactions in biological systems has been a defining evolutionary milestone for life on earth. One of the main conduits for energy capture is Photosystem II found in plants and algae. We are particularly interested in understanding how this system works and the copying it artificially. To that end we are using a range of spectroscopic and mutational approaches to understand the chemistry of water splitting and the chemistry of O2 reduction. These photosynthetic systems will provide important future biomimetic systems for energy storage on Earth.
Thylakoid Structure and Function - Dr
Fred Chow
The light-induced reactions of photosynthesis occur in plant thylakoid membranes which are intricately organised into stacked and non-stacked regions according to physicochemical principles. Optimisation of these light reactions is achieved through the dynamic localisation of the various supramolecular protein complexes in the thylakoid membrane domains. We are studying the mechanisms by which the thylakoid membrane system is organised, how the composition of the components influences the organisation and how the organisation in turn affects function. In particular, we aim to determine the dynamic structural/functional organization of the supramolecular protein complexes in dark and varying light conditions. To elucidate functional mechanisms, we monitor the various photosynthetic electron transfers in leaves, in optimal as well as stressful conditions, including high-light stress and drought.
Photosystem II utilizes solar energy to oxidize water into O2, hydrogen ions and electrons. Directly coupling this reaction to a hydrogen ion (H+) reducing reaction to produce H2 would create an unlimited, clean solar/hydrogen fuel cycle. To reach this goal we are carrying out fundamental studies on the development of light-activated biocatalysts by reverse engineering Photosystem II and biological hydrogenase functions into robust bacterial proteins. Our goal here is to oxidize water to O2 and reduce the protons to H2 using the unique properties of proteins to partition the two half- reactions within the same molecular assembly.
BioMolecular Spectroscopy - Instruments
Facilities that the PBE group has for general spectroscopy.
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People and Contacts
| Anderson, Jan |
Adjunct Professor |
| +61 2 6125 5895
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| Chow, Fred |
Professor |
| +61 2 6125 3980
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| Conlan, Brendon |
PhD Student |
| +61 2 6125 2386
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| Fallahi, Hossein |
PhD Student |
| +61 2 6125 4213
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| Hillier, Warwick |
Research Fellow |
| +61 2 6125 5894
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| Hingorani, Kastoori |
PhD Student |
| +61 2 6125 2386
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| Jia, Husen |
ARC Postdoctoral Fellow |
| +61 2 6125 2386
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| McConnell, Iain |
PhD Student |
| +61 2 6125 2386
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| Osmond, Barry |
Visiting Fellow |
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| Williamson, Adele |
PhD Student |
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| Wydrzynski, Thomas |
Senior Fellow (Group Leader) |
| +61 2 6125 5892
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Postal Address: |
Research School of Biological
Sciences
The Australian National University
Canberra ACT 0200
Australia |
Fax: |
(02) 6125 8056 |
| Campus Map: |
Building 46 <ANU link> |
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Student Opportunities
Applications for Australian Postgraduate Scholarships close October 31.
Lattest project updates from PBE <here>
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PBE Key Publications
Anderson JM and Chow WS (2002). Functional/structural dynamics of plant photosystem II. Philosophical Transactions of the Royal Society of London 357: 1421-1430.
Chow WS, Kim E-H, Horton P and Anderson JM (2005) Stacking of thylakoid membranes in chloroplasts: the physicochemical forces at work and the functional consequences that ensue. Photochemical & Photobiological Sciences 4: 1081-1090.
Chow WS and Hope AB (2004) Electron fluxes through Photosystem I in cucumber leaf discs probed by far-red light. Photosynthesis Research 81: 77-89.
Hay S, Wallace BB, Smith TA, Ghiggino KP and Wydrzynski T (2004) Protein engineering of cytochrome b562 for quinone binding and light-induced electron transfer. Proc Natl Acad Sci USA 101: 17675-17680.
Hillier, W. & Wydrzynski, T. (2008) 18O-Water Exchange in Photosystem II: Substrate Binding and Intermediates of the Water Splitting Reaction. Coordination Chemistry Reviews 252; 306-317.
Wydrzynski T and Satoh K, editors (2005) Photosystem II: The Light-Driven Water:Plastoquinone Oxidoreductase, Springer, Dordrecht, pp. 1-786. [ISBN-10: 1-4020-4249-3]
Ruban AV, Solovieva S, Lee PJ, Ilioaia C, Wentworth M, Ganeteg U, Klimmek F, Chow WS, Anderson JM, Jansson S and Horton P (2006) Plasticity in the composition of the light harvesting antenna of higher plants preserves structural integrity and biological function. Journal of Biological Chemistry 281: 14981-14990.
Strickler, MA, Hillier, W and Debus, RJ (2006) No evidence from FTIR spectroscopy that Glutamate 189 of the D1 polypeptide ligates the Manganese cluster in Photosystem II. Biochemistry 45, 8801-8811.
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PBE Recent Poster Presentations
Hillier, W., McConnell, I., Debus, R. & Wydrzynski, T. Photosynthetic Water Splitting <pdf>
Hingorani, K. & Wydrzynski, T. Artificial Photosynthesis: Molecular Engineering of Photoactive Proteins for Hydrogen Production <pdf>
International Conference on Photosynthesis: Glasgow UK, September 23-28 2007.
Losciale L., Oguchi R., Hendrickson L., Hope A.B., Corelli-Grappadelli L. & Chow W-S. A rapid, whole-tissue assay of PS II in leaves <pdf>.
Conlan B., Hillier W. & Wydrzynski T. Designing Artificial Photosynthesis: Production of a light activated metalloprotein <pdf>.
Hillier W., McConnell I., Singh S., Debus R., Boussac A. & Wydrzynski T. Substrate Water Oxygen Exchange in Photosystem II: insights from S-state intermediates, mutants and Ca vs Sr substitution <pdf>.
Fan D-Y., Hope A.B., Smith, P.J., Jia H., Pace R.J. Anderson J.M. & Chow W.S. Photosystem II / Photosystem I ratios in higher plants <pdf>.
McConnell I., Andreasson L.-E., Wydrzynski T. & Hillier W. Insights into the photosynthetic water oxdiation mechanism: Determination of the dissociation constants for the substrate water binding sites from 18O isotope exchange measurement <pdf>.
Williamson A., Hillier W. & Wydrzynski T. The MSP from a primative cyanobacterium <pdf>.
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