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Open Access
Abstract: The DIALS diffraction-modeling software package has been applied to serial crystallography data. Diffraction modeling is an exercise in determining the experimental parameters, such as incident beam wavelength, crystal unit cell and orientation, and detector geometry, that are most consistent with the observed positions of Bragg spots. These parameters can be refined by nonlinear least-squares fitting. In previous work, it has been challenging to refine both the positions of the sensors (metrology) on multipanel imaging detectors such as the CSPAD and the orientations of all of the crystals studied. Since the optimal models for metrology and crystal orientation are interdependent, alternate cycles of panel refinement and crystal refinement have been required. To simplify the process, a sparse linear algebra technique for solving the normal equations was implemented, allowing the detector panels to be refined simultaneously against the diffraction from thousands of crystals with excellent computational performance. Separately, it is shown how to refine the metrology of a second CSPAD detector, positioned at a distance of 2.5 m from the crystal, used for recording low-angle reflections. With the ability to jointly refine the detector position against the ensemble of all crystals used for structure determination, it is shown that ensemble refinement greatly reduces the apparent nonisomorphism that is often observed in the unit-cell distributions from still-shot serial crystallography. In addition, it is shown that batching the images by timestamp and re-refining the detector position can realistically model small, time-dependent variations in detector position relative to the sample, and thereby improve the integrated structure-factor intensity signal and heavy-atom anomalous peak heights.
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Sep 2018
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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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I24-Microfocus Macromolecular Crystallography
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E. Sethe
Burgie
,
Jonathan A.
Clinger
,
Mitchell D.
Miller
,
Aaron S.
Brewster
,
Pierre
Aller
,
Agata
Butryn
,
Franklin D.
Fuller
,
Sheraz
Gul
,
Iris D.
Young
,
Cindy C.
Pham
,
In-sik
Kim
,
Asmit
Bhowmick
,
Lee J.
O’riordan
,
Kyle D.
Sutherlin
,
Joshua V.
Heinemann
,
Alexander
Batyuk
,
Roberto
Alonso-mori
,
Mark S.
Hunter
,
Jason E.
Koglin
,
Junko
Yano
,
Vittal K.
Yachandra
,
Nicholas K.
Sauter
,
Aina E.
Cohen
,
Jan
Kern
,
Allen M.
Orville
,
George N.
Phillips
,
Richard D.
Vierstra
Diamond Proposal Number(s):
[19458]
Open Access
Abstract: A major barrier to defining the structural intermediates that arise during the reversible photointerconversion of phytochromes between their biologically inactive and active states has been the lack of crystals that faithfully undergo this transition within the crystal lattice. Here, we describe a crystalline form of the cyclic GMP phosphodiesterases/adenylyl cyclase/FhlA (GAF) domain from the cyanobacteriochrome PixJ in Thermosynechococcus elongatus assembled with phycocyanobilin that permits reversible photoconversion between the blue light-absorbing Pb and green light-absorbing Pg states, as well as thermal reversion of Pg back to Pb. The X-ray crystallographic structure of Pb matches previous models, including autocatalytic conversion of phycocyanobilin to phycoviolobilin upon binding and its tandem thioether linkage to the GAF domain. Cryocrystallography at 150 K, which compared diffraction data from a single crystal as Pb or after irradiation with blue light, detected photoconversion product(s) based on Fobs − Fobs difference maps that were consistent with rotation of the bonds connecting pyrrole rings C and D. Further spectroscopic analyses showed that phycoviolobilin is susceptible to X-ray radiation damage, especially as Pg, during single-crystal X-ray diffraction analyses, which could complicate fine mapping of the various intermediate states. Fortunately, we found that PixJ crystals are amenable to serial femtosecond crystallography (SFX) analyses using X-ray free-electron lasers (XFELs). As proof of principle, we solved by room temperature SFX the GAF domain structure of Pb to 1.55-Å resolution, which was strongly congruent with synchrotron-based models. Analysis of these crystals by SFX should now enable structural characterization of the early events that drive phytochrome photoconversion.
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Dec 2019
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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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Vivek
Srinivas
,
Rahul
Banerjee
,
Hugo
Lebrette
,
Jason C.
Jones
,
Oskar
Aurelius
,
In-sik
Kim
,
Cindy C.
Pham
,
Sheraz
Gul
,
Kyle
Sutherlin
,
Asmit
Bhowmick
,
Juliane
John
,
Esra
Bozkurt
,
Thomas
Fransson
,
Pierre
Aller
,
Agata
Butryn
,
Isabel
Bogacz
,
Philipp Stefan
Simon
,
Stephen
Keable
,
Alexander
Britz
,
Kensuke
Tono
,
Kyung-sook
Kim
,
Sang-youn
Park
,
Sang-jae
Lee
,
Jaehyun
Park
,
Roberto
Alonso-mori
,
Franklin
Fuller
,
Alexander
Batyuk
,
Aaron S.
Brewster
,
Uwe
Bergmann
,
Nicholas
Sauter
,
Allen M.
Orville
,
Vittal K.
Yachandra
,
Junko
Yano
,
John D.
Lipscomb
,
Jan F.
Kern
,
Martin
Högbom
Abstract: Soluble methane monooxygenase (sMMO) is a multicomponent metalloenzyme that catalyzes the conversion of methane to methanol at ambient temperature using a nonheme, oxygen-bridged dinuclear iron cluster in the active site. Structural changes in the hydroxylase component (sMMOH) containing the diiron cluster caused by complex formation with a regulatory component (MMOB) and by iron reduction are important for the regulation of O2 activation and substrate hydroxylation. Structural studies of metalloenzymes using traditional synchrotron-based X-ray crystallography are often complicated by partial X-ray-induced photoreduction of the metal center, thereby obviating determination of the structure of pure oxidation states. Here microcrystals of the sMMOH:MMOB complex from Methylosinus trichosporium OB3b were serially exposed to X-ray free electron laser (XFEL) pulses, where the ≦35 fs duration of exposure of an individual crystal yields diffraction data before photoreduction-induced structural changes can manifest. Merging diffraction patterns obtained from thousands of crystals generates radiation damage free, 1.95 Å resolution crystal structures for the fully oxidized and fully reduced states of the sMMOH:MMOB complex for the first time. The results provide new insight into the manner by which the diiron cluster and the active site environment are reorganized by the regulatory protein component in order to enhance the steps of oxygen activation and methane oxidation. This study also emphasizes the value of XFEL and serial femtosecond crystallography (SFX) methods for investigating the structures of metalloenzymes with radiation sensitive metal active sites.
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Jul 2020
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Herbert J.
Bernstein
,
Andreas
Forster
,
Asmit
Bhowmick
,
Aaron S.
Brewster
,
Sandor
Brockhauser
,
Luca
Gelisio
,
David R.
Hall
,
Filip
Leonarski
,
Valerio
Mariani
,
Gianluca
Santoni
,
Clemens
Vonrhein
,
Graeme
Winter
Open Access
Abstract: Macromolecular crystallography (MX) is the dominant means of determining the three-dimensional structures of biological macromolecules. Over the last few decades, most MX data have been collected at synchrotron beamlines using a large number of different detectors produced by various manufacturers and taking advantage of various protocols and goniometries. These data came in their own formats: sometimes proprietary, sometimes open. The associated metadata rarely reached the degree of completeness required for data management according to Findability, Accessibility, Interoperability and Reusability (FAIR) principles. Efforts to reuse old data by other investigators or even by the original investigators some time later were often frustrated. In the culmination of an effort dating back more than two decades, a large portion of the research community concerned with high data-rate macromolecular crystallography (HDRMX) has now agreed to an updated specification of data and metadata for diffraction images produced at synchrotron light sources and X-ray free-electron lasers (XFELs). This `Gold Standard' will facilitate the processing of data sets independent of the facility at which they were collected and enable data archiving according to FAIR principles, with a particular focus on interoperability and reusability. This agreed standard builds on the NeXus/HDF5 NXmx application definition and the International Union of Crystallography (IUCr) imgCIF/CBF dictionary, and it is compatible with major data-processing programs and pipelines. Just as with the IUCr CBF/imgCIF standard from which it arose and to which it is tied, the NeXus/HDF5 NXmx Gold Standard application definition is intended to be applicable to all detectors used for crystallography, and all hardware and software developers in the field are encouraged to adopt and contribute to the standard.
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Sep 2020
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