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Iris D.
Young
,
Mohamed
Ibrahim
,
Ruchira
Chatterjee
,
Sheraz
Gul
,
Franklin D.
Fuller
,
Sergey
Koroidov
,
Aaron S.
Brewster
,
Rosalie
Tran
,
Roberto
Alonso-mori
,
Thomas
Kroll
,
Tara
Michels-clark
,
Hartawan
Laksmono
,
Raymond G.
Sierra
,
Claudiu A.
Stan
,
Rana
Hussein
,
Miao
Zhang
,
Lacey
Douthit
,
Markus
Kubin
,
Casper
De Lichtenberg
,
Long
Vo Pham
,
Håkan
Nilsson
,
Mun Hon
Cheah
,
Dmitriy
Shevela
,
Claudio
Saracini
,
Mackenzie A.
Bean
,
Ina
Seuffert
,
Dimosthenis
Sokaras
,
Tsu-chien
Weng
,
Ernest
Pastor
,
Clemens
Weninger
,
Thomas
Fransson
,
Louise
Lassalle
,
Philipp
Bräuer
,
Pierre
Aller
,
Peter T.
Docker
,
Babak
Andi
,
Allen M.
Orville
,
James M.
Glownia
,
Silke
Nelson
,
Marcin
Sikorski
,
Diling
Zhu
,
Mark S.
Hunter
,
Thomas J.
Lane
,
Andy
Aquila
,
Jason E.
Koglin
,
Joseph
Robinson
,
Mengning
Liang
,
Sébastien
Boutet
,
Artem Y.
Lyubimov
,
Monarin
Uervirojnangkoorn
,
Nigel W.
Moriarty
,
Dorothee
Liebschner
,
Pavel V.
Afonine
,
David G.
Waterman
,
Gwyndaf
Evans
,
Philippe
Wernet
,
Holger
Dobbek
,
William I.
Weis
,
Axel T.
Brunger
,
Petrus H.
Zwart
,
Paul D.
Adams
,
Athina
Zouni
,
Johannes
Messinger
,
Uwe
Bergmann
,
Nicholas K.
Sauter
,
Jan
Kern
,
Vittal K.
Yachandra
,
Junko
Yano
Abstract: Light-induced oxidation of water by photosystem II (PS II) in plants, algae and cyanobacteria has generated most of the dioxygen in the atmosphere. PS II, a membrane-bound multi-subunit pigment protein complex, couples the one-electron photochemistry at the reaction centre with the four-electron redox chemistry of water oxidation at the Mn4CaO5 cluster in the oxygen-evolving complex (OEC). Under illumination, the OEC cycles through five intermediate S-states (S0 to S4)1, in which S1 is the dark-stable state and S3 is the last semi-stable state before O–O bond formation and O2 evolution2, 3. A detailed understanding of the O–O bond formation mechanism remains a challenge, and will require elucidation of both the structures of the OEC in the different S-states and the binding of the two substrate waters to the catalytic site4, 5, 6. Here we report the use of femtosecond pulses from an X-ray free electron laser (XFEL) to obtain damage-free, room temperature structures of dark-adapted (S1), two-flash illuminated (2F; S3-enriched), and ammonia-bound two-flash illuminated (2F-NH3; S3-enriched) PS II. Although the recent 1.95 Å resolution structure of PS II at cryogenic temperature using an XFEL7 provided a damage-free view of the S1 state, measurements at room temperature are required to study the structural landscape of proteins under functional conditions8, 9, and also for in situ advancement of the S-states. To investigate the water-binding site(s), ammonia, a water analogue, has been used as a marker, as it binds to the Mn4CaO5 cluster in the S2 and S3 states10. Since the ammonia-bound OEC is active, the ammonia-binding Mn site is not a substrate water site10, 11, 12, 13. This approach, together with a comparison of the native dark and 2F states, is used to discriminate between proposed O–O bond formation mechanisms.
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Nov 2016
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Jan
Kern
,
Ruchira
Chatterjee
,
Iris D.
Young
,
Franklin D.
Fuller
,
Louise
Lassalle
,
Mohamed
Ibrahim
,
Sheraz
Gul
,
Thomas
Fransson
,
Aaron S.
Brewster
,
Roberto
Alonso-mori
,
Rana
Hussein
,
Miao
Zhang
,
Lacey
Douthit
,
Casper
De Lichtenberg
,
Mun Hon
Cheah
,
Dmitry
Shevela
,
Julia
Wersig
,
Ina
Seuffert
,
Dimosthenis
Sokaras
,
Ernest
Pastor
,
Clemens
Weninger
,
Thomas
Kroll
,
Raymond G.
Sierra
,
Pierre
Aller
,
Agata
Butryn
,
Allen M.
Orville
,
Mengning
Liang
,
Alexander
Batyuk
,
Jason E.
Koglin
,
Sergio
Carbajo
,
Sébastien
Boutet
,
Nigel W.
Moriarty
,
James M.
Holton
,
Holger
Dobbek
,
Paul D.
Adams
,
Uwe
Bergmann
,
Nicholas K.
Sauter
,
Athina
Zouni
,
Johannes
Messinger
,
Junko
Yano
,
Vittal K.
Yachandra
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 complex3,4,5,6,7. 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.
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Nov 2018
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Mark
Könnecke
,
Frederick A.
Akeroyd
,
Herbert J.
Bernstein
,
Aaron S.
Brewster
,
Stuart
Campbell
,
Björn
Clausen
,
Stephen
Cottrell
,
Jens Uwe
Hoffmann
,
Pete R.
Jemian
,
David
Männicke
,
Raymond
Osborn
,
Peter F.
Peterson
,
Tobias
Richter
,
Jiro
Suzuki
,
Benjamin
Watts
,
Eugen
Wintersberger
,
Joachim
Wuttke
Open Access
Abstract: NeXus is an effort by an international group of scientists to define a common data exchange and archival format for neutron, X-ray and muon experiments. NeXus is built on top of the scientific data format HDF5 and adds domain-specific rules for organizing data within HDF5 files, in addition to a dictionary of well defined domain-specific field names. The NeXus data format has two purposes. First, it defines a format that can serve as a container for all relevant data associated with a beamline. This is a very important use case. Second, it defines standards in the form of application definitions for the exchange of data between applications. NeXus provides structures for raw experimental data as well as for processed data.
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Feb 2015
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Helen M. E.
Duyvesteyn
,
Helen M.
Ginn
,
Maija K.
Pietila
,
Armin
Wagner
,
Johan
Hattne
,
Jonathan M.
Grimes
,
Elina
Hirvonen
,
Gwyndaf
Evans
,
Marie-laure
Parsy
,
Nicholas K.
Sauter
,
Aaron S.
Brewster
,
Juha
Huiskonen
,
David I.
Stuart
,
Geoff
Sutton
,
Dennis H.
Bamford
Open Access
Abstract: Viruses are a significant threat to both human health and the economy, and there is an urgent need for novel anti-viral drugs and vaccines. High-resolution viral structures inform our understanding of the virosphere, and inspire novel therapies. Here we present a method of obtaining such structural information that avoids potentially disruptive handling, by collecting diffraction data from intact infected cells. We identify a suitable combination of cell type and virus to accumulate particles in the cells, establish a suitable time point where most cells contain virus condensates and use electron microscopy to demonstrate that these are ordered crystalline arrays of empty capsids. We then use an X-ray free electron laser to provide extremely bright illumination of sub-micron intracellular condensates of bacteriophage phiX174 inside living Escherichia coli at room temperature. We have been able to collect low resolution diffraction data. Despite the limited resolution and completeness of these initial data, due to a far from optimal experimental setup, we have used novel methodology to determine a putative space group, unit cell dimensions, particle packing and likely maturation state of the particles.
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Feb 2018
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Mohamed
Ibrahim
,
Thomas
Fransson
,
Ruchira
Chatterjee
,
Mun Hon
Cheah
,
Rana
Hussein
,
Louise
Lassalle
,
Kyle D.
Sutherlin
,
Iris D.
Young
,
Franklin D.
Fuller
,
Sheraz
Gul
,
In-sik
Kim
,
Philipp S.
Simon
,
Casper
De Lichtenberg
,
Petko
Chernev
,
Isabel
Bogacz
,
Cindy C.
Pham
,
Allen M.
Orville
,
Nicholas
Saichek
,
Trent
Northen
,
Alexander
Batyuk
,
Sergio
Carbajo
,
Roberto
Alonso-mori
,
Kensuke
Tono
,
Shigeki
Owada
,
Asmit
Bhowmick
,
Robert
Bolotovsky
,
Derek
Mendez
,
Nigel W.
Moriarty
,
James M.
Holton
,
Holger
Dobbek
,
Aaron S.
Brewster
,
Paul D.
Adams
,
Nicholas K.
Sauter
,
Uwe
Bergmann
,
Athina
Zouni
,
Johannes
Messinger
,
Jan
Kern
,
Vittal K.
Yachandra
,
Junko
Yano
Open Access
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.
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May 2020
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Data acquisition
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Open Access
Abstract: Data formats for recording X-ray diffraction data continue to evolve rapidly to accommodate new detector technologies developed in response to more intense light sources. Processing the data from single-crystal X-ray diffraction experiments therefore requires the ability to read, and correctly interpret, image data and metadata from a variety of instruments employing different experimental representations. Tools that have previously been developed to address this problem have been limited either by a lack of extensibility or by inconsistent treatment of image metadata. The dxtbx software package provides a consistent interface to both image data and experimental models, while supporting a completely generic user-extensible approach to reading the data files. The library is written in a mixture of C++ and Python and is distributed as part of the cctbx under an open-source licence at http://cctbx.sourceforge.net .
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Aug 2014
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