Natural and Artificial Photosynthesis

Photosynthetic organisms capture the energy of sunlight and store it in the chemical bonds of carbohydrates. Photosynthesis defines life as we know it by providing the building blocks of most living organisms and by producing atmospheric oxygen. The main engine of the photosynthetic apparatus is the enzyme Photosystem II (PS-II), where solar energy splits water into molecular oxygen, protons, and electrons, providing the reducing equivalents subsequently employed in carbon fixation. Elucidating the chemical and physical processes that underpin photosynthesis is a key step toward artificial photosynthesis, ultimately enabling the production of solar fuels from water using synthetic catalysts.

Research in the Pantazis group aims to uncover the intimate details of all biological photosynthetic processes at the atomic level, from light harvesting and water oxidation to CO2 fixation. In parallel we are studying synthetic systems that attempt to replicate these processes or mimic aspects of the biological system. Our strategy involves establishing highly accurate structure-property correlations as the basis for elucidating further mechanistic details. To this end we develop and apply accurate quantum chemical methods for the calculation of energetics, spin states, and spectroscopic properties such as those obtained from EPR and X-ray spectroscopies. Applications range in scale from small cluster models to whole membrane-embedded enzymes, using the complete arsenal of methods available to modern computational chemistry.

Representative publications:

D. A. Pantazis (2020) Evaluation of new low-valent computational models for the oxygen-evolving complex of photosystem II, Chem. Phys. Lett., 753, 137629.

D. A. Pantazis (2019) The S3 state of the Oxygen-Evolving Complex: Overview of Spectroscopy and XFEL Crystallography with a Critical Evaluation of Early-Onset Models for O-O Bond Formation, Inorganics, 7, 55.

 M. Chrysina, J. C. d. M. Silva, G. Zahariou, D. A. Pantazis and N. Ioannidis (2019) Proton Translocation via Tautomerization of Asn298 During the S2–S3 State Transition in the Oxygen-Evolving Complex of Photosystem II, J. Phys. Chem. B, 123, 3068-3078.

A. Sirohiwal, F. Neese, and D. A. Pantazis (2019) Microsolvation of the Redox-Active Tyrosine-D in Photosystem II: Correlation of Energetics with EPR Spectroscopy and Oxidation-Induced Proton Transfer, J. Am. Chem. Soc., 141, 3217-3231.

V. Krewald, F. Neese, and D. A. Pantazis (2019) Implications of Structural Heterogeneity for the Electronic Structure of the Final Oxygen-Evolving Intermediate in Photosystem II, J. Inorg. Biochem., 199, 110797.

D. A. Pantazis (2018) Missing Pieces in the Puzzle of Biological Water Oxidation, ACS Catal. 8, 9477-9507.

M. Retegan and D. A. Pantazis (2017) Differences in the active site of water oxidation among photosynthetic organisms, J. Am. Chem. Soc., 139, 14340-14343. (Cover Article)

M. Retegan and D. A. Pantazis (2016) Interaction of methanol with the oxygen-evolving complex: atomistic models, channel identification, species dependence, and mechanistic implications, Chem. Sci., 7, 6463-6476.

M. Retegan, V. Krewald, F. Mamedov, F. Neese, W. Lubitz, N. Cox, and D. A. Pantazis (2016) A five-coordinate Mn(IV) intermediate in biological water oxidation: spectroscopic signature and a pivot mechanism for water binding, Chem. Sci., 7, 72-84. (Cover Article)

V. Krewald, M. Retegan, N. Cox, J. Messinger, W. Lubitz, S. DeBeer, F. Neese, and D. A. Pantazis (2015) Metal oxidation states in biological water splitting, Chem. Sci., 6, 1676-1695.

N. Cox, M. Retegan, F. Neese, D. A. Pantazis, A. Boussac, and W. Lubitz (2014) Electronic structure of the oxygen-evolving complex in photosystem II prior to O-O bond formation, Science, 345, 804-808.

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