Photosynthetic water oxidation and O2-formation by plants, algae and cyanobacteria has shaped biosphere and atmosphere. The goal of this project is to understand the pivotal role of protonation dynamics in the redox chemistry of photosynthetic water oxidation. In classical and novel biophysical experiments, the functionally relevant proton movements are tracked with microsecond resolution, with a focus on time-resolved infrared spectroscopy. Moreover, the cyanobacterial photosystem II is genetically modified and, in a collaborative effort, structurally characterized by protein crystallography. The step toward atomistic understanding is approached jointly with the theory projects of the SFB.
Assunção, R., Zaharieva, I., and Dau, H. (2019). Ammonia as a substrate-water analogue in photosynthetic water oxidation: Influence on activation barrier of the O2-formation step. Biochim. Biophys. Acta 1860, 533-540, doi: 10.1016/j.bbabio.2019.04.005.
Bommer, M., Coates, L., Dau, H., Zouni, A., and Dobbek, H. (2017). Protein crystallization and initial neutron diffraction studies of the photosystem II subunit PsbO. Acta Crystallogr F Struct Biol Commun 73, 525-531.
Dau, H., Nürnberg, D. J., and Burnap, R. L. (2019). Local cycle of photosynthesis and quasi-aerobic respiration facilitated by manganese oxides – a hypothesis on the evolution of phototrophy. In: Bioenergetics: Oxygen Production and Reduction, eds. J. Barber, P. Nixon and A. V. Ruban, (World Scientific Publishers, Singapore), pg. 367-391, doi: 10.1142/9789813276925_0018.
Schuth, N., Liang, Z., Schonborn, M., Kussicke, A., Assuncao, R., Zaharieva, I., Zilliges, Y., and Dau, H. (2017). Inhibitory and Non-Inhibitory NH3 Binding at the Water-Oxidizing Manganese Complex of Photosystem II Suggests Possible Sites and a Rearrangement Mode of Substrate Water Molecules. Biochemistry 56, 6240-6256.
Schuth, N., Zaharieva, I., Chernev, P., Berggren, G., Anderlund, M., Styring, S., Dau, H., and Haumann, M. (2018). Kalpha X-ray Emission Spectroscopy on the Photosynthetic Oxygen-Evolving Complex Supports Manganese Oxidation and Water Binding in the S3 State. Inorg Chem 57,10424-10430.
Zaharieva, I., and Dau, H. (2019). Energetics and kinetics of S-state transitions monitored by delayed chlorophyll fluorescence. Frontiers in Plant Science Vol. 10, Article 386, doi: 10.3389/fpls.2019.00386.
Zhang, M., Bommer, M., Chatterjee, R., Hussein, R., Yano, J., Dau, H., Kern, J., Dobbek, H., and Zouni, A. (2017). Structural insights into the light-driven auto-assembly process of the water-oxidizing Mn4CaO5-cluster in photosystem II. eLife 6, DOI:10.7554/eLife.26933.
Bommer, M., Bondar, A.-N., Zouni, A., Dobbek, H., and Dau, H. (2016). Crystallographic and computational analysis of the barrel part of the PsbO protein of photosystem II - carboxylate-water clusters as putative proton transfer relays and structural switches. Biochemistry 55, 4626-4635.
Chernev, P., Zaharieva, I., Rossini, E., Galstyan, A., Dau, H., and Knapp, E.-W. (2016). Merging structural information from X-ray crystallography, quantum chemistry and EXAFS spectra: The oxygen-evolving complex in PSII. Journal of Physical Chemistry B 120, 10899-10922.
Damrow, R., Maldener, I., and Zilliges, Y. (2016). The Multiple Functions of Common Microbial Carbon Polymers, Glycogen and PHB, during Stress Responses in the Non-Diazotrophic Cyanobacterium Synechocystis sp. PCC 6803. Frontiers in Microbiology 7, 966.
Karge, O., Bondar, A.-N., and Dau, H. (2014). Cationic screening of charged surface groups (carboxylates) affects electron transfer steps in photosystem-II water oxidation and quinone reduction. Biochimica et Biophysica Acta (BBA) - Bioenergetics 1837, 1625-1634.
Klauss, A., Haumann, M., and Dau, H. (2015). Seven steps of alternating electron and proton transfer in photosystem II water oxidation traced by time-resolved photothermal beam deflection at improved sensitivity. J Phys Chem B 119, 2677-2689.
Zaharieva, I., Chernev, P., Berggren, G., Anderlund, M., Styring, S., Dau, H., and Haumann, M. (2016). Room-temperature energy-sampling K-beta X-ray emission spectroscopy of the Mn4Ca complex of photosynthesis reveals three manganese-centered oxidation steps and suggests a coordination change prior to O2 formation. Biochemistry 55, 4197-4211.
Zaharieva, I., Dau, H., and Haumann, M. (2016). Sequential and Coupled Proton and Electron Transfer Events in the S2 --> S3 Transition of Photosynthetic Water Oxidation Revealed by Time-Resolved X-ray Absorption Spectroscopy. Biochemistry 55, 6996-7004.
Zaharieva, I., González-Flores, D., Asfari, B., Pasquini, C., Mohammadi, M.R., Klingan, K., Zizak, I., Loos, S., Chernev, P., and Dau, H. (2016). Water oxidation catalysis – role of redox and structural dynamics in biological photosynthesis and inorganic manganese oxides. Energy Environ Sci 9, 2433-2443.
Zhang, C., Chen, C., Dong, H., Shen, J.-R., Dau, H., and Zhao, J. (2015). A synthetic Mn4Ca-cluster mimicking the oxygen-evolving center of photosynthesis. Science 348, 690-693.
Zilliges, Y. and Dau, H. (2016). Unexpected capacity for organic carbon assimilation by Thermosynechococcus elongatus, a crucial photosynthetic model organism. FEBS Letters 590, 962-970.