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Your search keyword '"Holton, James M."' showing total 11 results
Start Over Author "Holton, James M." Publisher umea universitet, kemiska institutionen
11 results on '"Holton, James M."'

1. Structural dynamics in the water and proton channels of photosystem II during the S2 to S3 transition

Author

Hussein, Rana, Ibrahim, Mohamed, Bhowmick, Asmit, Simon, Philipp S., Chatterjee, Ruchira, Lassalle, Louise, Doyle, Margaret, Bogacz, Isabel, Kim, In-Sik, Cheah, Mun Hon, Gul, Sheraz, de Lichtenberg, Casper, Chernev, Petko, Pham, Cindy C., Young, Iris D., Carbajo, Sergio, Fuller, Franklin D., Alonso-Mori, Roberto, Batyuk, Alex, Sutherlin, Kyle D., Brewster, Aaron S., Bolotovsky, Robert, Mendez, Derek, Holton, James M., Moriarty, Nigel W., Adams, Paul D., Bergmann, Uwe, Sauter, Nicholas K., Dobbek, Holger, Messinger, Johannes, Zouni, Athina, Kern, Jan, Yachandra, Vittal K., Yano, Junko, Hussein, Rana, Ibrahim, Mohamed, Bhowmick, Asmit, Simon, Philipp S., Chatterjee, Ruchira, Lassalle, Louise, Doyle, Margaret, Bogacz, Isabel, Kim, In-Sik, Cheah, Mun Hon, Gul, Sheraz, de Lichtenberg, Casper, Chernev, Petko, Pham, Cindy C., Young, Iris D., Carbajo, Sergio, Fuller, Franklin D., Alonso-Mori, Roberto, Batyuk, Alex, Sutherlin, Kyle D., Brewster, Aaron S., Bolotovsky, Robert, Mendez, Derek, Holton, James M., Moriarty, Nigel W., Adams, Paul D., Bergmann, Uwe, Sauter, Nicholas K., Dobbek, Holger, Messinger, Johannes, Zouni, Athina, Kern, Jan, Yachandra, Vittal K., and Yano, Junko

Abstract

Light-driven oxidation of water to molecular oxygen is catalyzed by the oxygen-evolving complex (OEC) in Photosystem II (PS II). This multi-electron, multi-proton catalysis requires the transport of two water molecules to and four protons from the OEC. A high-resolution 1.89 Å structure obtained by averaging all the S states and refining the data of various time points during the S2 to S3 transition has provided better visualization of the potential pathways for substrate water insertion and proton release. Our results indicate that the O1 channel is the likely water intake pathway, and the Cl1 channel is the likely proton release pathway based on the structural rearrangements of water molecules and amino acid side chains along these channels. In particular in the Cl1 channel, we suggest that residue D1-E65 serves as a gate for proton transport by minimizing the back reaction. The results show that the water oxidation reaction at the OEC is well coordinated with the amino acid side chains and the H-bonding network over the entire length of the channels, which is essential in shuttling substrate waters and protons.

Published
2021
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2. Structural dynamics in the water and proton channels of photosystem II during the S2 to S3 transition

Author

Hussein, Rana, Ibrahim, Mohamed, Bhowmick, Asmit, Simon, Philipp S., Chatterjee, Ruchira, Lassalle, Louise, Doyle, Margaret, Bogacz, Isabel, Kim, In-Sik, Cheah, Mun Hon, Gul, Sheraz, de Lichtenberg, Casper, Chernev, Petko, Pham, Cindy C., Young, Iris D., Carbajo, Sergio, Fuller, Franklin D., Alonso-Mori, Roberto, Batyuk, Alex, Sutherlin, Kyle D., Brewster, Aaron S., Bolotovsky, Robert, Mendez, Derek, Holton, James M., Moriarty, Nigel W., Adams, Paul D., Bergmann, Uwe, Sauter, Nicholas K., Dobbek, Holger, Messinger, Johannes, Zouni, Athina, Kern, Jan, Yachandra, Vittal K., Yano, Junko, Hussein, Rana, Ibrahim, Mohamed, Bhowmick, Asmit, Simon, Philipp S., Chatterjee, Ruchira, Lassalle, Louise, Doyle, Margaret, Bogacz, Isabel, Kim, In-Sik, Cheah, Mun Hon, Gul, Sheraz, de Lichtenberg, Casper, Chernev, Petko, Pham, Cindy C., Young, Iris D., Carbajo, Sergio, Fuller, Franklin D., Alonso-Mori, Roberto, Batyuk, Alex, Sutherlin, Kyle D., Brewster, Aaron S., Bolotovsky, Robert, Mendez, Derek, Holton, James M., Moriarty, Nigel W., Adams, Paul D., Bergmann, Uwe, Sauter, Nicholas K., Dobbek, Holger, Messinger, Johannes, Zouni, Athina, Kern, Jan, Yachandra, Vittal K., and Yano, Junko

Abstract

Light-driven oxidation of water to molecular oxygen is catalyzed by the oxygen-evolving complex (OEC) in Photosystem II (PS II). This multi-electron, multi-proton catalysis requires the transport of two water molecules to and four protons from the OEC. A high-resolution 1.89 Å structure obtained by averaging all the S states and refining the data of various time points during the S2 to S3 transition has provided better visualization of the potential pathways for substrate water insertion and proton release. Our results indicate that the O1 channel is the likely water intake pathway, and the Cl1 channel is the likely proton release pathway based on the structural rearrangements of water molecules and amino acid side chains along these channels. In particular in the Cl1 channel, we suggest that residue D1-E65 serves as a gate for proton transport by minimizing the back reaction. The results show that the water oxidation reaction at the OEC is well coordinated with the amino acid side chains and the H-bonding network over the entire length of the channels, which is essential in shuttling substrate waters and protons.

Published
2021
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3. Structural dynamics in the water and proton channels of photosystem II during the S2 to S3 transition

Author

Hussein, Rana, Ibrahim, Mohamed, Bhowmick, Asmit, Simon, Philipp S., Chatterjee, Ruchira, Lassalle, Louise, Doyle, Margaret, Bogacz, Isabel, Kim, In-Sik, Cheah, Mun Hon, Gul, Sheraz, de Lichtenberg, Casper, Chernev, Petko, Pham, Cindy C., Young, Iris D., Carbajo, Sergio, Fuller, Franklin D., Alonso-Mori, Roberto, Batyuk, Alex, Sutherlin, Kyle D., Brewster, Aaron S., Bolotovsky, Robert, Mendez, Derek, Holton, James M., Moriarty, Nigel W., Adams, Paul D., Bergmann, Uwe, Sauter, Nicholas K., Dobbek, Holger, Messinger, Johannes, Zouni, Athina, Kern, Jan, Yachandra, Vittal K., Yano, Junko, Hussein, Rana, Ibrahim, Mohamed, Bhowmick, Asmit, Simon, Philipp S., Chatterjee, Ruchira, Lassalle, Louise, Doyle, Margaret, Bogacz, Isabel, Kim, In-Sik, Cheah, Mun Hon, Gul, Sheraz, de Lichtenberg, Casper, Chernev, Petko, Pham, Cindy C., Young, Iris D., Carbajo, Sergio, Fuller, Franklin D., Alonso-Mori, Roberto, Batyuk, Alex, Sutherlin, Kyle D., Brewster, Aaron S., Bolotovsky, Robert, Mendez, Derek, Holton, James M., Moriarty, Nigel W., Adams, Paul D., Bergmann, Uwe, Sauter, Nicholas K., Dobbek, Holger, Messinger, Johannes, Zouni, Athina, Kern, Jan, Yachandra, Vittal K., and Yano, Junko

Abstract

Light-driven oxidation of water to molecular oxygen is catalyzed by the oxygen-evolving complex (OEC) in Photosystem II (PS II). This multi-electron, multi-proton catalysis requires the transport of two water molecules to and four protons from the OEC. A high-resolution 1.89 Å structure obtained by averaging all the S states and refining the data of various time points during the S2 to S3 transition has provided better visualization of the potential pathways for substrate water insertion and proton release. Our results indicate that the O1 channel is the likely water intake pathway, and the Cl1 channel is the likely proton release pathway based on the structural rearrangements of water molecules and amino acid side chains along these channels. In particular in the Cl1 channel, we suggest that residue D1-E65 serves as a gate for proton transport by minimizing the back reaction. The results show that the water oxidation reaction at the OEC is well coordinated with the amino acid side chains and the H-bonding network over the entire length of the channels, which is essential in shuttling substrate waters and protons.

Published
2021
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4. Reply to Wang et al: Clear evidence of binding of Ox to the oxygen-evolving complex of photosystem II is best observed in the omit map

Author

Ibrahim, Mohamed, Moriarty, Nigel W., Kern, Jan, Holton, James M., Brewster, Aaron S., Bhowmick, Asmit, Bergmann, Uwe, Zouni, Athina, Messinger, Johannes, Yachandra, Vittal K., Yano, Junko, Dobbek, Holger, Sauter, Nicholas K., Adams, Paul D., Ibrahim, Mohamed, Moriarty, Nigel W., Kern, Jan, Holton, James M., Brewster, Aaron S., Bhowmick, Asmit, Bergmann, Uwe, Zouni, Athina, Messinger, Johannes, Yachandra, Vittal K., Yano, Junko, Dobbek, Holger, Sauter, Nicholas K., and Adams, Paul D.

Abstract

This article has a letter. Please see relationship between letter and reply: https://www.pnas.org/content/118/24/e2023982118

Published
2021
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5. Structural dynamics in the water and proton channels of photosystem II during the S2 to S3 transition

Author

Hussein, Rana, Ibrahim, Mohamed, Bhowmick, Asmit, Simon, Philipp S., Chatterjee, Ruchira, Lassalle, Louise, Doyle, Margaret, Bogacz, Isabel, Kim, In-Sik, Cheah, Mun Hon, Gul, Sheraz, de Lichtenberg, Casper, Chernev, Petko, Pham, Cindy C., Young, Iris D., Carbajo, Sergio, Fuller, Franklin D., Alonso-Mori, Roberto, Batyuk, Alex, Sutherlin, Kyle D., Brewster, Aaron S., Bolotovsky, Robert, Mendez, Derek, Holton, James M., Moriarty, Nigel W., Adams, Paul D., Bergmann, Uwe, Sauter, Nicholas K., Dobbek, Holger, Messinger, Johannes, Zouni, Athina, Kern, Jan, Yachandra, Vittal K., Yano, Junko, Hussein, Rana, Ibrahim, Mohamed, Bhowmick, Asmit, Simon, Philipp S., Chatterjee, Ruchira, Lassalle, Louise, Doyle, Margaret, Bogacz, Isabel, Kim, In-Sik, Cheah, Mun Hon, Gul, Sheraz, de Lichtenberg, Casper, Chernev, Petko, Pham, Cindy C., Young, Iris D., Carbajo, Sergio, Fuller, Franklin D., Alonso-Mori, Roberto, Batyuk, Alex, Sutherlin, Kyle D., Brewster, Aaron S., Bolotovsky, Robert, Mendez, Derek, Holton, James M., Moriarty, Nigel W., Adams, Paul D., Bergmann, Uwe, Sauter, Nicholas K., Dobbek, Holger, Messinger, Johannes, Zouni, Athina, Kern, Jan, Yachandra, Vittal K., and Yano, Junko

Abstract

Light-driven oxidation of water to molecular oxygen is catalyzed by the oxygen-evolving complex (OEC) in Photosystem II (PS II). This multi-electron, multi-proton catalysis requires the transport of two water molecules to and four protons from the OEC. A high-resolution 1.89 Å structure obtained by averaging all the S states and refining the data of various time points during the S2 to S3 transition has provided better visualization of the potential pathways for substrate water insertion and proton release. Our results indicate that the O1 channel is the likely water intake pathway, and the Cl1 channel is the likely proton release pathway based on the structural rearrangements of water molecules and amino acid side chains along these channels. In particular in the Cl1 channel, we suggest that residue D1-E65 serves as a gate for proton transport by minimizing the back reaction. The results show that the water oxidation reaction at the OEC is well coordinated with the amino acid side chains and the H-bonding network over the entire length of the channels, which is essential in shuttling substrate waters and protons.

Published
2021
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6. Structural dynamics in the water and proton channels of photosystem II during the S2 to S3 transition

Author

Hussein, Rana, Ibrahim, Mohamed, Bhowmick, Asmit, Simon, Philipp S., Chatterjee, Ruchira, Lassalle, Louise, Doyle, Margaret, Bogacz, Isabel, Kim, In-Sik, Cheah, Mun Hon, Gul, Sheraz, de Lichtenberg, Casper, Chernev, Petko, Pham, Cindy C., Young, Iris D., Carbajo, Sergio, Fuller, Franklin D., Alonso-Mori, Roberto, Batyuk, Alex, Sutherlin, Kyle D., Brewster, Aaron S., Bolotovsky, Robert, Mendez, Derek, Holton, James M., Moriarty, Nigel W., Adams, Paul D., Bergmann, Uwe, Sauter, Nicholas K., Dobbek, Holger, Messinger, Johannes, Zouni, Athina, Kern, Jan, Yachandra, Vittal K., Yano, Junko, Hussein, Rana, Ibrahim, Mohamed, Bhowmick, Asmit, Simon, Philipp S., Chatterjee, Ruchira, Lassalle, Louise, Doyle, Margaret, Bogacz, Isabel, Kim, In-Sik, Cheah, Mun Hon, Gul, Sheraz, de Lichtenberg, Casper, Chernev, Petko, Pham, Cindy C., Young, Iris D., Carbajo, Sergio, Fuller, Franklin D., Alonso-Mori, Roberto, Batyuk, Alex, Sutherlin, Kyle D., Brewster, Aaron S., Bolotovsky, Robert, Mendez, Derek, Holton, James M., Moriarty, Nigel W., Adams, Paul D., Bergmann, Uwe, Sauter, Nicholas K., Dobbek, Holger, Messinger, Johannes, Zouni, Athina, Kern, Jan, Yachandra, Vittal K., and Yano, Junko

Abstract

Light-driven oxidation of water to molecular oxygen is catalyzed by the oxygen-evolving complex (OEC) in Photosystem II (PS II). This multi-electron, multi-proton catalysis requires the transport of two water molecules to and four protons from the OEC. A high-resolution 1.89 Å structure obtained by averaging all the S states and refining the data of various time points during the S2 to S3 transition has provided better visualization of the potential pathways for substrate water insertion and proton release. Our results indicate that the O1 channel is the likely water intake pathway, and the Cl1 channel is the likely proton release pathway based on the structural rearrangements of water molecules and amino acid side chains along these channels. In particular in the Cl1 channel, we suggest that residue D1-E65 serves as a gate for proton transport by minimizing the back reaction. The results show that the water oxidation reaction at the OEC is well coordinated with the amino acid side chains and the H-bonding network over the entire length of the channels, which is essential in shuttling substrate waters and protons.

Published
2021
Full Text
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7. Untangling the sequence of events during the S2 -> S3 transition in photosystem II and implications for the water oxidation mechanism

Author

Ibrahim, Mohamed, Fransson, Thomas, Chatterjee, Ruchira, Cheah, Mun Hon, Hussein, Rana, Lassalle, Louise, Sutherlin, Kyle D., Young, Iris D., Fuller, Franklin D., Gul, Sheraz, Kim, In-Sik, Simon, Philipp S., de Lichtenberg, Casper, Chernev, Petko, Bogacz, Isabel, Pham, Cindy C., Orville, Allen M., Saichek, Nicholas, Northen, Trent, Batyuk, Alexander, Carbajo, Sergio, Alonso-Mori, Roberto, Tono, Kensuke, Owada, Shigeki, Bhowmick, Asmit, Bolotovsky, Robert, Mendez, Derek, Moriarty, Nigel W., Holton, James M., Dobbek, Holger, Brewster, Aaron S., Adams, Paul D., Sauter, Nicholas K., Bergmann, Uwe, Zouni, Athina, Messinger, Johannes, Kern, Jan, Yachandra, Vittal K., Yano, Junko, Ibrahim, Mohamed, Fransson, Thomas, Chatterjee, Ruchira, Cheah, Mun Hon, Hussein, Rana, Lassalle, Louise, Sutherlin, Kyle D., Young, Iris D., Fuller, Franklin D., Gul, Sheraz, Kim, In-Sik, Simon, Philipp S., de Lichtenberg, Casper, Chernev, Petko, Bogacz, Isabel, Pham, Cindy C., Orville, Allen M., Saichek, Nicholas, Northen, Trent, Batyuk, Alexander, Carbajo, Sergio, Alonso-Mori, Roberto, Tono, Kensuke, Owada, Shigeki, Bhowmick, Asmit, Bolotovsky, Robert, Mendez, Derek, Moriarty, Nigel W., Holton, James M., Dobbek, Holger, Brewster, Aaron S., Adams, Paul D., Sauter, Nicholas K., Bergmann, Uwe, Zouni, Athina, Messinger, Johannes, Kern, Jan, Yachandra, Vittal K., and Yano, Junko

Abstract

In oxygenic photosynthesis, light-driven oxidation of water to molecular oxygen is carried out by the oxygen-evolving complex (OEC) in photosystem II (PS II). Recently, we reported the room-temperature structures of PS II in the four (semi)stable S-states, S1, S2, S3, and S0, showing that a water molecule is inserted during the S2 -> S3 transition, as a new bridging O(H)-ligand between Mn1 and Ca. To understand the sequence of events leading to the formation of this last stable intermediate state before O2 formation, we recorded diffraction and Mn X-ray emission spectroscopy (XES) data at several time points during the S2 -> S3 transition. At the electron acceptor site, changes due to the two-electron redox chemistry at the quinones, QA and QB, are observed. At the donor site, tyrosine YZ and His190 H-bonded to it move by 50 μs after the second flash, and Glu189 moves away from Ca. This is followed by Mn1 and Mn4 moving apart, and the insertion of OX(H) at the open coordination site of Mn1. This water, possibly a ligand of Ca, could be supplied via a "water wheel"-like arrangement of five waters next to the OEC that is connected by a large channel to the bulk solvent. XES spectra show that Mn oxidation (τ of ∼350 μs) during the S2 -> S3 transition mirrors the appearance of OX electron density. This indicates that the oxidation state change and the insertion of water as a bridging atom between Mn1 and Ca are highly correlated.

Published
2020
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8. Untangling the sequence of events during the S2 -> S3 transition in photosystem II and implications for the water oxidation mechanism

Author

Ibrahim, Mohamed, Fransson, Thomas, Chatterjee, Ruchira, Cheah, Mun Hon, Hussein, Rana, Lassalle, Louise, Sutherlin, Kyle D., Young, Iris D., Fuller, Franklin D., Gul, Sheraz, Kim, In-Sik, Simon, Philipp S., de Lichtenberg, Casper, Chernev, Petko, Bogacz, Isabel, Pham, Cindy C., Orville, Allen M., Saichek, Nicholas, Northen, Trent, Batyuk, Alexander, Carbajo, Sergio, Alonso-Mori, Roberto, Tono, Kensuke, Owada, Shigeki, Bhowmick, Asmit, Bolotovsky, Robert, Mendez, Derek, Moriarty, Nigel W., Holton, James M., Dobbek, Holger, Brewster, Aaron S., Adams, Paul D., Sauter, Nicholas K., Bergmann, Uwe, Zouni, Athina, Messinger, Johannes, Kern, Jan, Yachandra, Vittal K., Yano, Junko, Ibrahim, Mohamed, Fransson, Thomas, Chatterjee, Ruchira, Cheah, Mun Hon, Hussein, Rana, Lassalle, Louise, Sutherlin, Kyle D., Young, Iris D., Fuller, Franklin D., Gul, Sheraz, Kim, In-Sik, Simon, Philipp S., de Lichtenberg, Casper, Chernev, Petko, Bogacz, Isabel, Pham, Cindy C., Orville, Allen M., Saichek, Nicholas, Northen, Trent, Batyuk, Alexander, Carbajo, Sergio, Alonso-Mori, Roberto, Tono, Kensuke, Owada, Shigeki, Bhowmick, Asmit, Bolotovsky, Robert, Mendez, Derek, Moriarty, Nigel W., Holton, James M., Dobbek, Holger, Brewster, Aaron S., Adams, Paul D., Sauter, Nicholas K., Bergmann, Uwe, Zouni, Athina, Messinger, Johannes, Kern, Jan, Yachandra, Vittal K., and Yano, Junko

Abstract

In oxygenic photosynthesis, light-driven oxidation of water to molecular oxygen is carried out by the oxygen-evolving complex (OEC) in photosystem II (PS II). Recently, we reported the room-temperature structures of PS II in the four (semi)stable S-states, S1, S2, S3, and S0, showing that a water molecule is inserted during the S2 -> S3 transition, as a new bridging O(H)-ligand between Mn1 and Ca. To understand the sequence of events leading to the formation of this last stable intermediate state before O2 formation, we recorded diffraction and Mn X-ray emission spectroscopy (XES) data at several time points during the S2 -> S3 transition. At the electron acceptor site, changes due to the two-electron redox chemistry at the quinones, QA and QB, are observed. At the donor site, tyrosine YZ and His190 H-bonded to it move by 50 μs after the second flash, and Glu189 moves away from Ca. This is followed by Mn1 and Mn4 moving apart, and the insertion of OX(H) at the open coordination site of Mn1. This water, possibly a ligand of Ca, could be supplied via a "water wheel"-like arrangement of five waters next to the OEC that is connected by a large channel to the bulk solvent. XES spectra show that Mn oxidation (τ of ∼350 μs) during the S2 -> S3 transition mirrors the appearance of OX electron density. This indicates that the oxidation state change and the insertion of water as a bridging atom between Mn1 and Ca are highly correlated.

Published
2020
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9. Untangling the sequence of events during the S2 -> S3 transition in photosystem II and implications for the water oxidation mechanism

Author

Ibrahim, Mohamed, Fransson, Thomas, Chatterjee, Ruchira, Cheah, Mun Hon, Hussein, Rana, Lassalle, Louise, Sutherlin, Kyle D., Young, Iris D., Fuller, Franklin D., Gul, Sheraz, Kim, In-Sik, Simon, Philipp S., de Lichtenberg, Casper, Chernev, Petko, Bogacz, Isabel, Pham, Cindy C., Orville, Allen M., Saichek, Nicholas, Northen, Trent, Batyuk, Alexander, Carbajo, Sergio, Alonso-Mori, Roberto, Tono, Kensuke, Owada, Shigeki, Bhowmick, Asmit, Bolotovsky, Robert, Mendez, Derek, Moriarty, Nigel W., Holton, James M., Dobbek, Holger, Brewster, Aaron S., Adams, Paul D., Sauter, Nicholas K., Bergmann, Uwe, Zouni, Athina, Messinger, Johannes, Kern, Jan, Yachandra, Vittal K., Yano, Junko, Ibrahim, Mohamed, Fransson, Thomas, Chatterjee, Ruchira, Cheah, Mun Hon, Hussein, Rana, Lassalle, Louise, Sutherlin, Kyle D., Young, Iris D., Fuller, Franklin D., Gul, Sheraz, Kim, In-Sik, Simon, Philipp S., de Lichtenberg, Casper, Chernev, Petko, Bogacz, Isabel, Pham, Cindy C., Orville, Allen M., Saichek, Nicholas, Northen, Trent, Batyuk, Alexander, Carbajo, Sergio, Alonso-Mori, Roberto, Tono, Kensuke, Owada, Shigeki, Bhowmick, Asmit, Bolotovsky, Robert, Mendez, Derek, Moriarty, Nigel W., Holton, James M., Dobbek, Holger, Brewster, Aaron S., Adams, Paul D., Sauter, Nicholas K., Bergmann, Uwe, Zouni, Athina, Messinger, Johannes, Kern, Jan, Yachandra, Vittal K., and Yano, Junko

Abstract

In oxygenic photosynthesis, light-driven oxidation of water to molecular oxygen is carried out by the oxygen-evolving complex (OEC) in photosystem II (PS II). Recently, we reported the room-temperature structures of PS II in the four (semi)stable S-states, S1, S2, S3, and S0, showing that a water molecule is inserted during the S2 -> S3 transition, as a new bridging O(H)-ligand between Mn1 and Ca. To understand the sequence of events leading to the formation of this last stable intermediate state before O2 formation, we recorded diffraction and Mn X-ray emission spectroscopy (XES) data at several time points during the S2 -> S3 transition. At the electron acceptor site, changes due to the two-electron redox chemistry at the quinones, QA and QB, are observed. At the donor site, tyrosine YZ and His190 H-bonded to it move by 50 μs after the second flash, and Glu189 moves away from Ca. This is followed by Mn1 and Mn4 moving apart, and the insertion of OX(H) at the open coordination site of Mn1. This water, possibly a ligand of Ca, could be supplied via a "water wheel"-like arrangement of five waters next to the OEC that is connected by a large channel to the bulk solvent. XES spectra show that Mn oxidation (τ of ∼350 μs) during the S2 -> S3 transition mirrors the appearance of OX electron density. This indicates that the oxidation state change and the insertion of water as a bridging atom between Mn1 and Ca are highly correlated.

Published
2020
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10. Untangling the sequence of events during the S2 -> S3 transition in photosystem II and implications for the water oxidation mechanism

Author

Ibrahim, Mohamed, Fransson, Thomas, Chatterjee, Ruchira, Cheah, Mun Hon, Hussein, Rana, Lassalle, Louise, Sutherlin, Kyle D., Young, Iris D., Fuller, Franklin D., Gul, Sheraz, Kim, In-Sik, Simon, Philipp S., de Lichtenberg, Casper, Chernev, Petko, Bogacz, Isabel, Pham, Cindy C., Orville, Allen M., Saichek, Nicholas, Northen, Trent, Batyuk, Alexander, Carbajo, Sergio, Alonso-Mori, Roberto, Tono, Kensuke, Owada, Shigeki, Bhowmick, Asmit, Bolotovsky, Robert, Mendez, Derek, Moriarty, Nigel W., Holton, James M., Dobbek, Holger, Brewster, Aaron S., Adams, Paul D., Sauter, Nicholas K., Bergmann, Uwe, Zouni, Athina, Messinger, Johannes, Kern, Jan, Yachandra, Vittal K., Yano, Junko, Ibrahim, Mohamed, Fransson, Thomas, Chatterjee, Ruchira, Cheah, Mun Hon, Hussein, Rana, Lassalle, Louise, Sutherlin, Kyle D., Young, Iris D., Fuller, Franklin D., Gul, Sheraz, Kim, In-Sik, Simon, Philipp S., de Lichtenberg, Casper, Chernev, Petko, Bogacz, Isabel, Pham, Cindy C., Orville, Allen M., Saichek, Nicholas, Northen, Trent, Batyuk, Alexander, Carbajo, Sergio, Alonso-Mori, Roberto, Tono, Kensuke, Owada, Shigeki, Bhowmick, Asmit, Bolotovsky, Robert, Mendez, Derek, Moriarty, Nigel W., Holton, James M., Dobbek, Holger, Brewster, Aaron S., Adams, Paul D., Sauter, Nicholas K., Bergmann, Uwe, Zouni, Athina, Messinger, Johannes, Kern, Jan, Yachandra, Vittal K., and Yano, Junko

Abstract

In oxygenic photosynthesis, light-driven oxidation of water to molecular oxygen is carried out by the oxygen-evolving complex (OEC) in photosystem II (PS II). Recently, we reported the room-temperature structures of PS II in the four (semi)stable S-states, S1, S2, S3, and S0, showing that a water molecule is inserted during the S2 -> S3 transition, as a new bridging O(H)-ligand between Mn1 and Ca. To understand the sequence of events leading to the formation of this last stable intermediate state before O2 formation, we recorded diffraction and Mn X-ray emission spectroscopy (XES) data at several time points during the S2 -> S3 transition. At the electron acceptor site, changes due to the two-electron redox chemistry at the quinones, QA and QB, are observed. At the donor site, tyrosine YZ and His190 H-bonded to it move by 50 μs after the second flash, and Glu189 moves away from Ca. This is followed by Mn1 and Mn4 moving apart, and the insertion of OX(H) at the open coordination site of Mn1. This water, possibly a ligand of Ca, could be supplied via a "water wheel"-like arrangement of five waters next to the OEC that is connected by a large channel to the bulk solvent. XES spectra show that Mn oxidation (τ of ∼350 μs) during the S2 -> S3 transition mirrors the appearance of OX electron density. This indicates that the oxidation state change and the insertion of water as a bridging atom between Mn1 and Ca are highly correlated.

Published
2020
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11. Structures of the intermediates of Kok’s photosynthetic water oxidation clock

Author

Kern, Jan, Chatterjee, Ruchira, Young, Iris D., Fuller, Franklin D., Lassalle, Louise, Ibrahim, Mohamed, Gul, Sheraz, Fransson, Thomas, Brewster, Aaron S., Alonso-Mori, Roberto, Hussein, Rana, Zhang, Miao, Douthit, Lacey, de Lichtenberg, Casper, Cheah, Mun Hon, Shevela, Dmitriy, Wersig, Julia, Seuffert, Ina, Sokaras, Dimosthenis, Pastor, Ernest, Weninger, Clemens, Kroll, Thomas, Sierra, Raymond G., Aller, Pierre, Butryn, Agata, Orville, Allen M., Liang, Mengning, Batyuk, Alexander, Koglin, Jason E., Carbajo, Sergio, Boutet, Sébastien, Moriarty, Nigel W., Holton, James M., Dobbek, Holger, Adams, Paul D., Bergmann, Uwe, Sauter, Nicholas K., Zouni, Athina, Messinger, Johannes, Yano, Junko, Yachandra, Vittal K., Kern, Jan, Chatterjee, Ruchira, Young, Iris D., Fuller, Franklin D., Lassalle, Louise, Ibrahim, Mohamed, Gul, Sheraz, Fransson, Thomas, Brewster, Aaron S., Alonso-Mori, Roberto, Hussein, Rana, Zhang, Miao, Douthit, Lacey, de Lichtenberg, Casper, Cheah, Mun Hon, Shevela, Dmitriy, Wersig, Julia, Seuffert, Ina, Sokaras, Dimosthenis, Pastor, Ernest, Weninger, Clemens, Kroll, Thomas, Sierra, Raymond G., Aller, Pierre, Butryn, Agata, Orville, Allen M., Liang, Mengning, Batyuk, Alexander, Koglin, Jason E., Carbajo, Sergio, Boutet, Sébastien, Moriarty, Nigel W., Holton, James M., Dobbek, Holger, Adams, Paul D., Bergmann, Uwe, Sauter, Nicholas K., Zouni, Athina, Messinger, Johannes, Yano, Junko, and Yachandra, Vittal K.

Abstract

Inspired by the period-four oscillation in flash-induced oxygen evolution of photosystem II discovered by Joliot in 1969, Kok performed additional experiments and proposed a five-state kinetic model for photosynthetic oxygen evolution, known as Kok’s S-state clock or cycle1,2. The model comprises four (meta)stable intermediates (S0, S1, S2 and S3) and one transient S4 state, which precedes dioxygen formation occurring in a concerted reaction from two water-derived oxygens bound at an oxo-bridged tetra manganese calcium (Mn4CaO5) cluster in the oxygen-evolving complex3–7. This reaction is coupled to the two-step reduction and protonation of the mobile plastoquinone QB at the acceptor side of PSII. Here, using serial femtosecond X-ray crystallography and simultaneous X-ray emission spectroscopy with multi-flash visible laser excitation at room temperature, we visualize all (meta)stable states of Kok’s cycle as high-resolution structures (2.04–2.08 Å). In addition, we report structures of two transient states at 150 and 400 µs, revealing notable structural changes including the binding of one additional ‘water’, Ox, during the S2→S3 state transition. Our results suggest that one water ligand to calcium (W3) is directly involved in substrate delivery. The binding of the additional oxygen Ox in the S3 state between Ca and Mn1 supports O–O bond formation mechanisms involving O5 as one substrate, where Ox is either the other substrate oxygen or is perfectly positioned to refill the O5 position during O2 release. Thus, our results exclude peroxo-bond formation in the S3 state, and the nucleophilic attack of W3 onto W2 is unlikely.

Published
2018
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