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Hervin F, Fromme P. Guided wave skew velocity correction in anisotropic laminates. Ultrasonics 2023; 133:107047. [PMID: 37253300 DOI: 10.1016/j.ultras.2023.107047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 03/15/2023] [Accepted: 05/14/2023] [Indexed: 06/01/2023]
Abstract
Guided ultrasonic wave propagation in anisotropic structures results in directional dependency of velocity and wave skewing effects that can impact the accuracy of damage detection. Phase and group velocities of the A0 guided wave mode, propagating in a unidirectional carbon fiber reinforced laminate, were investigated experimentally and through finite element analysis. A correction for the significant offset in phase and group velocities due to wave skewing effects is illustrated for both point and short line sources, achieving good agreement with theoretical calculations assuming planar wave fronts. The influence of the line excitation length on velocity measurements is discussed.
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Affiliation(s)
- F Hervin
- Department of Mechanical Engineering, University College London (UCL), UK.
| | - P Fromme
- Department of Mechanical Engineering, University College London (UCL), UK
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2
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Shoukroun D, Doherty A, Endrizzi M, Bate D, Fromme P, Olivo A. Post-acquisition mask misalignment correction for edge illumination x-ray phase contrast imaging. Rev Sci Instrum 2022; 93:053706. [PMID: 35649794 DOI: 10.1063/5.0090517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 05/05/2022] [Indexed: 06/15/2023]
Abstract
Edge illumination x-ray phase contrast imaging uses a set of apertured masks to translate phase effects into variation of detected intensity. While the system is relatively robust against misalignment, mask movement during acquisition can lead to gradient artifacts. A method has been developed to correct the images by quantifying the misalignment post-acquisition and implementing correction maps to remove the gradient artifact. Images of a woven carbon fiber composite plate containing porosity were used as examples to demonstrate the image correction process. The gradient formed during image acquisition was removed without affecting the image quality, and results were subsequently used for quantification of porosity, indicating that the gradient correction did not affect the quantitative content of the images.
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Affiliation(s)
- D Shoukroun
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom
| | - A Doherty
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom
| | - M Endrizzi
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom
| | - D Bate
- Nikon, X-Tek Systems, Ltd., Tring, Hertfordshire HP23 4JX, United Kingdom
| | - P Fromme
- Department of Mechanical Engineering, University College London, London WC1E 6BT, United Kingdom
| | - A Olivo
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom
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3
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Nass K, Redecke L, Perbandt M, Yefanov O, Klinge M, Koopmann R, Stellato F, Gabdulkhakov A, Schönherr R, Rehders D, Lahey-Rudolph JM, Aquila A, Barty A, Basu S, Doak RB, Duden R, Frank M, Fromme R, Kassemeyer S, Katona G, Kirian R, Liu H, Majoul I, Martin-Garcia JM, Messerschmidt M, Shoeman RL, Weierstall U, Westenhoff S, White TA, Williams GJ, Yoon CH, Zatsepin N, Fromme P, Duszenko M, Chapman HN, Betzel C. In cellulo crystallization of Trypanosoma brucei IMP dehydrogenase enables the identification of genuine co-factors. Nat Commun 2020; 11:620. [PMID: 32001697 PMCID: PMC6992785 DOI: 10.1038/s41467-020-14484-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 01/06/2020] [Indexed: 02/07/2023] Open
Abstract
Sleeping sickness is a fatal disease caused by the protozoan parasite Trypanosoma brucei (Tb). Inosine-5’-monophosphate dehydrogenase (IMPDH) has been proposed as a potential drug target, since it maintains the balance between guanylate deoxynucleotide and ribonucleotide levels that is pivotal for the parasite. Here we report the structure of TbIMPDH at room temperature utilizing free-electron laser radiation on crystals grown in living insect cells. The 2.80 Å resolution structure reveals the presence of ATP and GMP at the canonical sites of the Bateman domains, the latter in a so far unknown coordination mode. Consistent with previously reported IMPDH complexes harboring guanosine nucleotides at the second canonical site, TbIMPDH forms a compact oligomer structure, supporting a nucleotide-controlled conformational switch that allosterically modulates the catalytic activity. The oligomeric TbIMPDH structure we present here reveals the potential of in cellulo crystallization to identify genuine allosteric co-factors from a natural reservoir of specific compounds. Trypanosoma brucei inosine-5′-monophosphate dehydrogenase (IMPDH) is an enzyme in the guanine nucleotide biosynthesis pathway and of interest as a drug target. Here the authors present the 2.8 Å room temperature structure of TbIMPDH determined by utilizing X-ray free-electron laser radiation and crystals that were grown in insect cells and find that ATP and GMP are bound at the canonical sites of the Bateman domains.
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Affiliation(s)
- Karol Nass
- Center for Free-Electron Laser Science (CFEL), Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany.,Paul Scherrer Institute (PSI), Forschungstrasse 111, 5232, Villigen, PSI, Switzerland
| | - Lars Redecke
- Joint Laboratory for Structural Biology of Infection and Inflammation, Institute of Biochemistry and Molecular Biology, University of Hamburg, and Institute of Biochemistry, University of Lübeck, at Deutsches Elektronen-Synchrotron (DESY), Notkestr. 85, 22607, Hamburg, Germany.,German Centre for Infection Research, University of Lübeck, 23562, Lübeck, Germany.,Institute of Biochemistry, University of Lübeck, Ratzeburger Allee 160, 23562, Lübeck, Germany.,Deutsches Elektronen Synchrotron (DESY), Photon Science, Notkestr. 85, 22607, Hamburg, Germany
| | - M Perbandt
- Institute of Biochemistry and Molecular Biology, University of Hamburg, at Deutsches Elektronen-Synchrotron (DESY), Notkestr. 85, 22607, Hamburg, Germany.,The Hamburg Centre for Ultrafast Imaging (CUI), Luruper Chaussee 149, 22761, Hamburg, Germany
| | - O Yefanov
- Center for Free-Electron Laser Science (CFEL), Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
| | - M Klinge
- Joint Laboratory for Structural Biology of Infection and Inflammation, Institute of Biochemistry and Molecular Biology, University of Hamburg, and Institute of Biochemistry, University of Lübeck, at Deutsches Elektronen-Synchrotron (DESY), Notkestr. 85, 22607, Hamburg, Germany.,BioAgilytix Europe GmbH, Lademannbogen 10, 22339, Hamburg, Germany
| | - R Koopmann
- Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe-Seyler-Str.4, 72076, Tübingen, Germany
| | - F Stellato
- Center for Free-Electron Laser Science (CFEL), Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany.,Dipartimento di Fisica, Università di Roma Tor Vergata and INFN, Via della Ricerca Scientifica 1, 00133, Rome, Italy
| | - A Gabdulkhakov
- Institute of Protein Research, Russian Academy of Sciences, 4 Institutskaya Str., Pushchino, Moscow Region, Russia, 142290
| | - R Schönherr
- Institute of Biochemistry, University of Lübeck, Ratzeburger Allee 160, 23562, Lübeck, Germany.,Deutsches Elektronen Synchrotron (DESY), Photon Science, Notkestr. 85, 22607, Hamburg, Germany
| | - D Rehders
- Joint Laboratory for Structural Biology of Infection and Inflammation, Institute of Biochemistry and Molecular Biology, University of Hamburg, and Institute of Biochemistry, University of Lübeck, at Deutsches Elektronen-Synchrotron (DESY), Notkestr. 85, 22607, Hamburg, Germany.,BODE Chemie GmbH, Melanchthonstraße 27, 22525, Hamburg, Germany
| | - J M Lahey-Rudolph
- Center for Free-Electron Laser Science (CFEL), Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany.,Institute of Biochemistry, University of Lübeck, Ratzeburger Allee 160, 23562, Lübeck, Germany
| | - A Aquila
- Center for Free-Electron Laser Science (CFEL), Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany.,LCLS, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - A Barty
- Center for Free-Electron Laser Science (CFEL), Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
| | - S Basu
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ, 85287-160, USA.,European Molecular Biology Laboratory (EMBL), Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, Grenoble, France
| | - R B Doak
- Department of Physics, Arizona State University, Tempe, AZ, 85411, USA.,Max Planck Institute for Medical Research, Jahnstr. 29, 69120, Heidelberg, Germany
| | - R Duden
- Institute of Biology, University of Lübeck, Ratzeburger Allee 160, 23562, Lübeck, Germany
| | - M Frank
- Biology and Biotechnology Division, Physical & Life Sciences Directorate, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA, 94550, USA
| | - R Fromme
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ, 85287-160, USA
| | - S Kassemeyer
- Max-Planck-Institute for Medical Research, Jahnstr. 29, 69120, Heidelberg, Germany
| | - G Katona
- Department of Chemistry and Molecular Biology, University of Gothenburg, 40530, Gothenburg, Sweden
| | - R Kirian
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ, 85287-160, USA
| | - H Liu
- Department of Physics, Arizona State University, Tempe, AZ, 85411, USA.,Complex Systems Division, Beijing Computational Science Research Center, 100193, Beijing, China
| | - I Majoul
- Institute of Biology, University of Lübeck, Ratzeburger Allee 160, 23562, Lübeck, Germany
| | - J M Martin-Garcia
- Center for Applied Structural Discovery (CASD), Biodesign Institute, Arizona State University, 727 East Tyler Street, Tempe, AZ, 85287, USA
| | - M Messerschmidt
- LCLS, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA.,Center for Applied Structural Discovery (CASD), Biodesign Institute, Arizona State University, 727 East Tyler Street, Tempe, AZ, 85287, USA
| | - R L Shoeman
- Max-Planck-Institute for Medical Research, Jahnstr. 29, 69120, Heidelberg, Germany
| | - U Weierstall
- Department of Physics, Arizona State University, Tempe, AZ, 85411, USA
| | - S Westenhoff
- Department of Chemistry and Molecular Biology, University of Gothenburg, 40530, Gothenburg, Sweden
| | - T A White
- Center for Free-Electron Laser Science (CFEL), Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
| | - G J Williams
- LCLS, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA.,Brookhaven National Laboratory (BNL), PO Box 5000, Upton, NY, 11973-5000, USA
| | - C H Yoon
- Center for Free-Electron Laser Science (CFEL), Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany.,LCLS, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - N Zatsepin
- Department of Physics, Arizona State University, Tempe, AZ, 85411, USA.,ARC Centre of Excellence in Advanced Molecular Imaging, Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Victoria, 3086, Australia
| | - P Fromme
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ, 85287-160, USA
| | - M Duszenko
- Institute of Neurophysiology, University of Tübingen, Keplerstr. 15, 72074, Tübingen, Germany
| | - H N Chapman
- Center for Free-Electron Laser Science (CFEL), Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany.,The Hamburg Centre for Ultrafast Imaging (CUI), Luruper Chaussee 149, 22761, Hamburg, Germany.,Department of Physics, University of Hamburg, Luruper Chaussee 149, 22761, Hamburg, Germany
| | - C Betzel
- Institute of Biochemistry and Molecular Biology, University of Hamburg, at Deutsches Elektronen-Synchrotron (DESY), Notkestr. 85, 22607, Hamburg, Germany. .,The Hamburg Centre for Ultrafast Imaging (CUI), Luruper Chaussee 149, 22761, Hamburg, Germany.
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4
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Botha S, Martin-Garcia J, Hu H, Weierstall U, Fuchs M, Shi W, Andi B, Skinner J, Bernstein H, Fromme P, Zatsepin N. Single-wavelength anomalous dispersion phasing for serial millisecond snapshot crystallography. Acta Crystallogr A Found Adv 2019. [DOI: 10.1107/s0108767319098970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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5
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Kissick DJ, Martin-Garcia JM, Hu H, Venugopalan N, Xu S, Corcoran S, Ferguson D, Hilgart MC, Makarov O, Xu Q, Ogata C, Stepanov S, Thifault D, Marlowe T, Alvarado C, Zacks M, Cance W, Fromme P, Fischetti RF. Improvements in serial crystallography capabilities at GM/CA. Acta Crystallogr A Found Adv 2019. [DOI: 10.1107/s010876731909562x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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6
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Zatsepin N, Botha S, Martin-Garcia J, Hu H, Weierstall U, Shi W, Andi B, Skinner J, Bernstein H, Fromme P, Fuchs M. Optimizing data quality in injector-based serial millisecond crystallography. Acta Crystallogr A Found Adv 2019. [DOI: 10.1107/s0108767319096259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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7
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Fischetti RF, Martin-Garcia J, Zatsepin N, Stander N, Zhu L, Subramanian G, Nelson G, Coe J, Nagaratnam N, Roy-Chowdury S, Kissick D, Ishchenko A, Conrad C, Ketawala G, James D, Zook J, Ogata C, Venugopalan N, Xu S, Meents A, Srajer V, Henning R, Chapman H, Spence J, Weierstall U, Cherezov V, Fromme P, Liu W. Monochromatic and polychromatic serial crystallography at the Advanced Photon Source. Acta Crystallogr A Found Adv 2017. [DOI: 10.1107/s0108767317096404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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8
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Stagno JR, Liu Y, Bhandari YR, Conrad CE, Panja S, Swain M, Fan L, Nelson G, Li C, Wendel DR, White TA, Coe JD, Wiedorn MO, Knoska J, Oberthuer D, Tuckey RA, Yu P, Dyba M, Tarasov SG, Weierstall U, Grant TD, Schwieters CD, Zhang J, Ferré-D'Amaré AR, Fromme P, Draper DE, Liang M, Hunter MS, Boutet S, Tan K, Zuo X, Ji X, Barty A, Zatsepin NA, Chapman HN, Spence JCH, Woodson SA, Wang YX. Structures of riboswitch RNA reaction states by mix-and-inject XFEL serial crystallography. Acta Crystallogr A Found Adv 2017. [DOI: 10.1107/s0108767317099081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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9
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Perera SM, Xu X, Struts A, Chawla U, Boutet S, Carbajo S, Seaberg M, Hunter M, Martin-Garcia J, Coe J, Wiedorn M, Nelson G, Chamberlain S, Deponte D, Fromme R, Grant T, Kirian R, Fromme P, Brown M. Time-Resolved Wide-Angle X-Ray Scattering Reveals Protein Quake in Rhodopsin Activation. Biophys J 2017. [DOI: 10.1016/j.bpj.2016.11.2740] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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10
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Kärtner F, Ahr F, Calendron AL, Çankaya H, Carbajo S, Chang G, Cirmi G, Dörner K, Dorda U, Fallahi A, Hartin A, Hemmer M, Hobbs R, Hua Y, Huang W, Letrun R, Matlis N, Mazalova V, Mücke O, Nanni E, Putnam W, Ravi K, Reichert F, Sarrou I, Wu X, Yahaghi A, Ye H, Zapata L, Zhang D, Zhou C, Miller R, Berggren K, Graafsma H, Meents A, Assmann R, Chapman H, Fromme P. AXSIS: Exploring the frontiers in attosecond X-ray science, imaging and spectroscopy. Nucl Instrum Methods Phys Res A 2016; 829:24-29. [PMID: 28706325 PMCID: PMC5502815 DOI: 10.1016/j.nima.2016.02.080] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
X-ray crystallography is one of the main methods to determine atomic-resolution 3D images of the whole spectrum of molecules ranging from small inorganic clusters to large protein complexes consisting of hundred-thousands of atoms that constitute the macromolecular machinery of life. Life is not static, and unravelling the structure and dynamics of the most important reactions in chemistry and biology is essential to uncover their mechanism. Many of these reactions, including photosynthesis which drives our biosphere, are light induced and occur on ultrafast timescales. These have been studied with high time resolution primarily by optical spectroscopy, enabled by ultrafast laser technology, but they reduce the vast complexity of the process to a few reaction coordinates. In the AXSIS project at CFEL in Hamburg, funded by the European Research Council, we develop the new method of attosecond serial X-ray crystallography and spectroscopy, to give a full description of ultrafast processes atomically resolved in real space and on the electronic energy landscape, from co-measurement of X-ray and optical spectra, and X-ray diffraction. This technique will revolutionize our understanding of structure and function at the atomic and molecular level and thereby unravel fundamental processes in chemistry and biology like energy conversion processes. For that purpose, we develop a compact, fully coherent, THz-driven atto-second X-ray source based on coherent inverse Compton scattering off a free-electron crystal, to outrun radiation damage effects due to the necessary high X-ray irradiance required to acquire diffraction signals. This highly synergistic project starts from a completely clean slate rather than conforming to the specifications of a large free-electron laser (FEL) user facility, to optimize the entire instrumentation towards fundamental measurements of the mechanism of light absorption and excitation energy transfer. A multidisciplinary team formed by laser-, accelerator,- X-ray scientists as well as spectroscopists and biochemists optimizes X-ray pulse parameters, in tandem with sample delivery, crystal size, and advanced X-ray detectors. Ultimately, the new capability, attosecond serial X-ray crystallography and spectroscopy, will be applied to one of the most important problems in structural biology, which is to elucidate the dynamics of light reactions, electron transfer and protein structure in photosynthesis.
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Affiliation(s)
- F.X. Kärtner
- Center for Free-Electron Laser Science, Hamburg, Germany
- Institute for Experimental Physics, University of Hamburg, Hamburg, Germany
- The Hamburg Center for Ultrafast Imaging, Hamburg, Germany
- DESY, Hamburg, Germany
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - F. Ahr
- Center for Free-Electron Laser Science, Hamburg, Germany
- Institute for Experimental Physics, University of Hamburg, Hamburg, Germany
- DESY, Hamburg, Germany
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany
| | - A.-L. Calendron
- Center for Free-Electron Laser Science, Hamburg, Germany
- Institute for Experimental Physics, University of Hamburg, Hamburg, Germany
- The Hamburg Center for Ultrafast Imaging, Hamburg, Germany
- DESY, Hamburg, Germany
| | - H. Çankaya
- Center for Free-Electron Laser Science, Hamburg, Germany
- The Hamburg Center for Ultrafast Imaging, Hamburg, Germany
- DESY, Hamburg, Germany
| | - S. Carbajo
- Center for Free-Electron Laser Science, Hamburg, Germany
- Institute for Experimental Physics, University of Hamburg, Hamburg, Germany
- DESY, Hamburg, Germany
| | - G. Chang
- Center for Free-Electron Laser Science, Hamburg, Germany
- The Hamburg Center for Ultrafast Imaging, Hamburg, Germany
- DESY, Hamburg, Germany
| | - G. Cirmi
- Center for Free-Electron Laser Science, Hamburg, Germany
- The Hamburg Center for Ultrafast Imaging, Hamburg, Germany
- DESY, Hamburg, Germany
| | - K. Dörner
- Center for Free-Electron Laser Science, Hamburg, Germany
- DESY, Hamburg, Germany
| | | | - A. Fallahi
- Center for Free-Electron Laser Science, Hamburg, Germany
- DESY, Hamburg, Germany
| | - A. Hartin
- Center for Free-Electron Laser Science, Hamburg, Germany
- Institute for Experimental Physics, University of Hamburg, Hamburg, Germany
- DESY, Hamburg, Germany
| | - M. Hemmer
- Center for Free-Electron Laser Science, Hamburg, Germany
- DESY, Hamburg, Germany
| | - R. Hobbs
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Y. Hua
- Center for Free-Electron Laser Science, Hamburg, Germany
- Institute for Experimental Physics, University of Hamburg, Hamburg, Germany
- DESY, Hamburg, Germany
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany
| | - W.R. Huang
- Center for Free-Electron Laser Science, Hamburg, Germany
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - R. Letrun
- Center for Free-Electron Laser Science, Hamburg, Germany
- DESY, Hamburg, Germany
| | - N. Matlis
- Center for Free-Electron Laser Science, Hamburg, Germany
- DESY, Hamburg, Germany
| | - V. Mazalova
- Center for Free-Electron Laser Science, Hamburg, Germany
- DESY, Hamburg, Germany
| | - O.D. Mücke
- Center for Free-Electron Laser Science, Hamburg, Germany
- The Hamburg Center for Ultrafast Imaging, Hamburg, Germany
- DESY, Hamburg, Germany
| | - E. Nanni
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - W. Putnam
- Center for Free-Electron Laser Science, Hamburg, Germany
- Institute for Experimental Physics, University of Hamburg, Hamburg, Germany
- The Hamburg Center for Ultrafast Imaging, Hamburg, Germany
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - K. Ravi
- Center for Free-Electron Laser Science, Hamburg, Germany
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - F. Reichert
- Center for Free-Electron Laser Science, Hamburg, Germany
- Institute for Experimental Physics, University of Hamburg, Hamburg, Germany
| | - I. Sarrou
- Center for Free-Electron Laser Science, Hamburg, Germany
- DESY, Hamburg, Germany
| | - X. Wu
- Center for Free-Electron Laser Science, Hamburg, Germany
- The Hamburg Center for Ultrafast Imaging, Hamburg, Germany
- DESY, Hamburg, Germany
| | - A. Yahaghi
- Center for Free-Electron Laser Science, Hamburg, Germany
- DESY, Hamburg, Germany
| | - H. Ye
- Center for Free-Electron Laser Science, Hamburg, Germany
- Institute for Experimental Physics, University of Hamburg, Hamburg, Germany
- The Hamburg Center for Ultrafast Imaging, Hamburg, Germany
- DESY, Hamburg, Germany
| | - L. Zapata
- Center for Free-Electron Laser Science, Hamburg, Germany
| | - D. Zhang
- Center for Free-Electron Laser Science, Hamburg, Germany
- Institute for Experimental Physics, University of Hamburg, Hamburg, Germany
- DESY, Hamburg, Germany
| | - C. Zhou
- Center for Free-Electron Laser Science, Hamburg, Germany
- Institute for Experimental Physics, University of Hamburg, Hamburg, Germany
- DESY, Hamburg, Germany
| | - R.J.D. Miller
- Center for Free-Electron Laser Science, Hamburg, Germany
- The Hamburg Center for Ultrafast Imaging, Hamburg, Germany
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany
| | - K.K. Berggren
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | - A. Meents
- Center for Free-Electron Laser Science, Hamburg, Germany
- DESY, Hamburg, Germany
| | | | - H.N. Chapman
- Center for Free-Electron Laser Science, Hamburg, Germany
- Institute for Experimental Physics, University of Hamburg, Hamburg, Germany
- The Hamburg Center for Ultrafast Imaging, Hamburg, Germany
- DESY, Hamburg, Germany
| | - P. Fromme
- Center for Free-Electron Laser Science, Hamburg, Germany
- DESY, Hamburg, Germany
- Arizona State University, School of Molecular Sciences and Center for Applied Structural Discovery, The Biodesign Institute, Tempe, AZ, USA
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11
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Hadjipanteli A, Kourkoumelis N, Fromme P, Huang J, Speller R. Evaluation of the 3D spatial distribution of the Calcium/Phosphorus ratio in bone using computed-tomography dual-energy analysis. Phys Med 2016; 32:162-8. [DOI: 10.1016/j.ejmp.2015.11.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 07/29/2015] [Accepted: 11/07/2015] [Indexed: 01/30/2023] Open
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12
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Hadjipanteli A, Kourkoumelis N, Fromme P, Olivo A, Huang J, Speller R. A new technique for the assessment of the 3D spatial distribution of the calcium/phosphorus ratio in bone apatite. Physiol Meas 2013; 34:1399-410. [DOI: 10.1088/0967-3334/34/11/1399] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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13
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Redecke L, Betzel C, Rehders D, Nass K, DePonte DP, White T, Duszenko M, Spence J, Fromme P, Schlichting I, Chapman H. Free electron laser radiation and in vivogrown nano-crystals open new routes in structural biology and options for time-resolved experiments. Acta Crystallogr A 2013. [DOI: 10.1107/s0108767313099789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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14
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Newcombe L, Dewar M, Blunn GW, Fromme P. Effect of amputation level on the stress transferred to the femur by an artificial limb directly attached to the bone. Med Eng Phys 2013; 35:1744-53. [PMID: 23953406 DOI: 10.1016/j.medengphy.2013.07.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 04/30/2013] [Accepted: 07/23/2013] [Indexed: 11/19/2022]
Abstract
Attachment of an artificial limb directly to the skeleton has a number of potential benefits and the technique has been implemented for several amputation sites. In this paper the transfer of stress from an external, transfemoral prosthesis to the femur during normal walking activity is investigated. The stress distribution in the femur and at the implant-bone interface is calculated using finite element analysis for the 3D geometry and inhomogeneous, anisotropic material properties obtained from a CT scan of a healthy femur. Attachment of the prosthetic leg at three different levels of amputation is considered. Stress concentrations are found at the distal end of the bone and adjacent to the implant tip and stress shielding is observed adjacent to the implant. It is found that the stress distribution in the femur distal to the epiphysis, where the femur geometry is close to cylindrical, can be predicted from a cylindrical finite element model, using the correct choice of bone diameter as measured from a radiograph. Proximal to the lesser trochanter the stress decreases as the femur geometry diverges significantly from a cylinder. The stress concentration at the distal, resected end of the bone is removed when a collared implant is employed. These findings form the basis for appropriate settings of an external fail-safe device to protect the bone from excessive stress in the event of an undue load.
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Affiliation(s)
- L Newcombe
- UCL Institute of Biomedical Engineering (IBME), John Scales Centre for Biomedical Engineering, Institute of Orthopaedics and Musculoskeletal Science, University College London, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, Middlesex HA7 4LP, UK; UCL Institute of Biomedical Engineering (IBME), Department of Mechanical Engineering, University College London, London WC1E 7JE, UK
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Johansson LC, Arnlund D, Katona G, Malmerberg E, Fromme P, Chapman HN, Neutze R. Serial femtosecond crystallography using crystals grown in lipidic-sponge phases. Acta Crystallogr A 2012. [DOI: 10.1107/s0108767312099436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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16
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Arnlund D, Johansson L, Katona G, Malmerberg E, Davidsson J, Barty A, Schlichting I, Boutet S, Fromme P, Spence J, Chapman H, Neutze R. Visualising rapid structural changes in photosynthetic reaction centres with XFEL radiation. Acta Crystallogr A 2012. [DOI: 10.1107/s010876731209976x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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17
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Fromme P, Chapman H, Kupitz C, Hunter MS, Kirian RA, Barty A, White TA, Aquilla A, Stellato F, Beyerlein K, DePonte DP, Frank M, Schlichting I, Shoeman R, Lomb L, Steinbrenner J, Nass K, Boutet S, Bogan MJ, Williams G, Zatsepin N, Basu S, Wang D, James D, Fromme R, Grotjohann I, Bottin H, Cherezov V, Stevens R, Cobbe D, Cramer W, Stroud R, Doak RB, Weierstall U, Schmidt K, Spence JCH. Femtosecond nanocrystallography of membrane proteins opens a new era for structural biology. Acta Crystallogr A 2012. [DOI: 10.1107/s0108767312099461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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18
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Neutze R, Johansson L, Wöhri A, Katona G, Malmerberg E, Arnlund D, Davidsson J, Wulff M, Groenhof G, Chapman H, Spence J, Fromme P. Potential impact of an X-FEL on time-resolved studies of protein dynamics. Acta Crystallogr A 2011. [DOI: 10.1107/s0108767311097777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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19
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Hunter MS, DePonte DP, Shapiro DA, Kirian RA, Wang X, Starodub D, Marchesini S, Weierstall U, Doak RB, Spence JCH, Fromme P. X-ray diffraction from membrane protein nanocrystals. Biophys J 2011; 100:198-206. [PMID: 21190672 DOI: 10.1016/j.bpj.2010.10.049] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Revised: 10/02/2010] [Accepted: 10/13/2010] [Indexed: 11/25/2022] Open
Abstract
Membrane proteins constitute > 30% of the proteins in an average cell, and yet the number of currently known structures of unique membrane proteins is < 300. To develop new concepts for membrane protein structure determination, we have explored the serial nanocrystallography method, in which fully hydrated protein nanocrystals are delivered to an x-ray beam within a liquid jet at room temperature. As a model system, we have collected x-ray powder diffraction data from the integral membrane protein Photosystem I, which consists of 36 subunits and 381 cofactors. Data were collected from crystals ranging in size from 100 nm to 2 μm. The results demonstrate that there are membrane protein crystals that contain < 100 unit cells (200 total molecules) and that 3D crystals of membrane proteins, which contain < 200 molecules, may be suitable for structural investigation. Serial nanocrystallography overcomes the problem of x-ray damage, which is currently one of the major limitations for x-ray structure determination of small crystals. By combining serial nanocrystallography with x-ray free-electron laser sources in the future, it may be possible to produce molecular-resolution electron-density maps using membrane protein crystals that contain only a few hundred or thousand unit cells.
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Affiliation(s)
- M S Hunter
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona, USA
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20
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Semoroz A, Masserey B, Fromme P. Monitoring of hidden damage in multi-layered aerospace structures using high-frequency guided waves. ACTA ACUST UNITED AC 2011. [DOI: 10.1117/12.879913] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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22
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Gräber P, Fromme P, Junesch U, Schmidt G, Thulke G. Kinetics of Proton-Transport-Coupled ATP Synthesis Catalyzed by the Chloroplast ATP Synthase. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/bbpc.19860901120] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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23
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Shapiro DA, Chapman HN, Deponte D, Doak RB, Fromme P, Hembree G, Hunter M, Marchesini S, Schmidt K, Spence J, Starodub D, Weierstall U. Powder diffraction from a continuous microjet of submicrometer protein crystals. J Synchrotron Radiat 2008; 15:593-9. [PMID: 18955765 DOI: 10.1107/s0909049508024151] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2008] [Accepted: 07/29/2008] [Indexed: 05/06/2023]
Abstract
Atomic-resolution structures from small proteins have recently been determined from high-quality powder diffraction patterns using a combination of stereochemical restraints and Rietveld refinement [Von Dreele (2007), J. Appl. Cryst. 40, 133-143; Margiolaki et al. (2007), J. Am. Chem. Soc. 129, 11865-11871]. While powder diffraction data have been obtained from batch samples of small crystal-suspensions, which are exposed to X-rays for long periods of time and undergo significant radiation damage, the proof-of-concept that protein powder diffraction data from nanocrystals of a membrane protein can be obtained using a continuous microjet is shown. This flow-focusing aerojet has been developed to deliver a solution of hydrated protein nanocrystals to an X-ray beam for diffraction analysis. This method requires neither the crushing of larger polycrystalline samples nor any techniques to avoid radiation damage such as cryocooling. Apparatus to record protein powder diffraction in this manner has been commissioned, and in this paper the first powder diffraction patterns from a membrane protein, photosystem I, with crystallite sizes of less than 500 nm are presented. These preliminary patterns show the lowest-order reflections, which agree quantitatively with theoretical calculations of the powder profile. The results also serve to test our aerojet injector system, with future application to femtosecond diffraction in free-electron X-ray laser schemes, and for serial crystallography using a single-file beam of aligned hydrated molecules.
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Affiliation(s)
- D A Shapiro
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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Shapiro D, Deponte D, Doak B, Fromme P, Hembree G, Hunter M, Marchesini S, Schmidt K, Spence J. Serial crystallography: use of a micro-jet for diffraction of protein nano-crystals or molecules. Acta Crystallogr A 2008. [DOI: 10.1107/s0108767308099170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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25
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Masserey B, Fromme P, Thompson DO, Chimenti DE. IN-SITU MONITORING OF FATIGUE CRACK GROWTH AT FASTENER HOLES USING RAYLEIGH-LIKE WAVES. ACTA ACUST UNITED AC 2008. [DOI: 10.1063/1.2902611] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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26
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Starodub D, Rez P, Hembree G, Howells M, Shapiro D, Chapman HN, Fromme P, Schmidt K, Weierstall U, Doak RB, Spence JCH. Dose, exposure time and resolution in serial X-ray crystallography. J Synchrotron Radiat 2008; 15:62-73. [PMID: 18097080 DOI: 10.1107/s0909049507048893] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2007] [Accepted: 10/05/2007] [Indexed: 05/25/2023]
Abstract
The resolution of X-ray diffraction microscopy is limited by the maximum dose that can be delivered prior to sample damage. In the proposed serial crystallography method, the damage problem is addressed by distributing the total dose over many identical hydrated macromolecules running continuously in a single-file train across a continuous X-ray beam, and resolution is then limited only by the available molecular and X-ray fluxes and molecular alignment. Orientation of the diffracting molecules is achieved by laser alignment. The incident X-ray fluence (energy/area) is evaluated that is required to obtain a given resolution from (i) an analytical model, giving the count rate at the maximum scattering angle for a model protein, (ii) explicit simulation of diffraction patterns for a GroEL-GroES protein complex, and (iii) the spatial frequency cut-off of the transfer function following iterative solution of the phase problem, and reconstruction of an electron density map in the projection approximation. These calculations include counting shot noise and multiple starts of the phasing algorithm. The results indicate counting time and the number of proteins needed within the beam at any instant for a given resolution and X-ray flux. An inverse fourth-power dependence of exposure time on resolution is confirmed, with important implications for all coherent X-ray imaging. It is found that multiple single-file protein beams will be needed for sub-nanometer resolution on current third-generation synchrotrons, but not on fourth-generation designs, where reconstruction of secondary protein structure at a resolution of 7 A should be possible with relatively short exposures.
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Affiliation(s)
- D Starodub
- Department of Physics, Arizona State University, PO Box 871504, Tempe, AZ 85287-1504, USA.
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Spence JC, Doak B, Weierstall U, Schmidt K, Fromme P, Starodub D, Wu J, Hembree G, Howells M, Shapiro D, Chapman H. Diffraction from a laser-aligned beam of hydrated proteins. Acta Crystallogr A 2005. [DOI: 10.1107/s0108767305095103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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28
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Spence JCH, Schmidt K, Wu JS, Hembree G, Weierstall U, Doak B, Fromme P. Diffraction and imaging from a beam of laser-aligned proteins: resolution limits. Acta Crystallogr A 2005; 61:237-45. [PMID: 15724074 DOI: 10.1107/s0108767305002710] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2004] [Accepted: 01/24/2005] [Indexed: 11/10/2022] Open
Abstract
The effect of the limited alignment of hydrated molecules is considered in a laser-aligned molecular beam, on diffraction patterns taken from the beam. Simulated patterns for a protein beam are inverted using the Fienup-Gerchberg-Saxton phasing algorithm, and the effect of limited alignment on the resolution of the resulting potential maps is studied. For a typical protein molecule (lysozyme) with anisotropic polarizability, it is found that up to 1 kW of continuous-wave near-infrared laser power (depending on dielectric constant), together with cooling to liquid-nitrogen temperatures, may be needed to produce sufficiently accurate alignment for direct observation of the secondary structure of proteins in the reconstructed potential or charge-density map. For a typical virus (TMV), a 50 W continuous-wave laser is adequate for subnanometre resolution at room temperature. The dependence of resolution on laser power, temperature, molecular size, shape and dielectric constant is analyzed.
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Affiliation(s)
- J C H Spence
- Department of Physics and Astronomy, Arizona State University, Tempe, AZ 85287-1504, USA.
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29
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Abstract
In plants and cyanobacteria, the primary step in oxygenic photosynthesis, the light induced charge separation, is driven by two large membrane intrinsic protein complexes, the photosystems I and II. Photosystem I catalyses the light driven electron transfer from plastocyanin/cytochrome c(6) on the lumenal side of the membrane to ferredoxin/flavodoxin at the stromal side by a chain of electron carriers. Photosystem I of Synechococcus elongatus consists of 12 protein subunits, 96 chlorophyll a molecules, 22 carotenoids, three [4Fe4S] clusters and two phylloquinones. Furthermore, it has been discovered that four lipids are intrinsic components of photosystem I. Photosystem I exists as a trimer in the native membrane with a molecular mass of 1068 kDa for the whole complex. The X-ray structure of photosystem I at a resolution of 2.5 A shows the location of the individual subunits and cofactors and provides new information on the protein-cofactor interactions. [P. Jordan, P. Fromme, H.T. Witt, O. Klukas, W. Saenger, N. Krauss, Nature 411 (2001) 909-917]. In this review, biochemical data and results of biophysical investigations are discussed with respect to the X-ray crystallographic structure in order to give an overview of the structure and function of this large membrane protein.
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Affiliation(s)
- P Fromme
- Max Volmer Laboratorium für Biophysikalische Chemie Institut für Chemie, Technische Universität Berlin, Germany.
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30
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Abstract
Life on Earth depends on photosynthesis, the conversion of light energy from the Sun to chemical energy. In plants, green algae and cyanobacteria, this process is driven by the cooperation of two large protein-cofactor complexes, photosystems I and II, which are located in the thylakoid photosynthetic membranes. The crystal structure of photosystem I from the thermophilic cyanobacterium Synechococcus elongatus described here provides a picture at atomic detail of 12 protein subunits and 127 cofactors comprising 96 chlorophylls, 2 phylloquinones, 3 Fe4S4 clusters, 22 carotenoids, 4 lipids, a putative Ca2+ ion and 201 water molecules. The structural information on the proteins and cofactors and their interactions provides a basis for understanding how the high efficiency of photosystem I in light capturing and electron transfer is achieved.
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Affiliation(s)
- P Jordan
- Institut für Chemie/Kristallographie, Freie Universität Berlin, D-14195 Berlin, Takustrasse 6, Germany
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31
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Hofbauer W, Zouni A, Bittl R, Kern J, Orth P, Lendzian F, Fromme P, Witt HT, Lubitz W. Photosystem II single crystals studied by EPR spectroscopy at 94 GHz: the tyrosine radical Y(D)(*). Proc Natl Acad Sci U S A 2001; 98:6623-8. [PMID: 11381107 PMCID: PMC34403 DOI: 10.1073/pnas.101127598] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Electron paramagnetic resonance (EPR) spectroscopy at 94 GHz is used to study the dark-stable tyrosine radical Y(D)(*) in single crystals of photosystem II core complexes (cc) isolated from the thermophilic cyanobacterium Synechococcus elongatus. These complexes contain at least 17 subunits, including the water-oxidizing complex (WOC), and 32 chlorophyll a molecules/PS II; they are active in light-induced electron transfer and water oxidation. The crystals belong to the orthorhombic space group P2(1)2(1)2(1), with four PS II dimers per unit cell. High-frequency EPR is used for enhancing the sensitivity of experiments performed on small single crystals as well as for increasing the spectral resolution of the g tensor components and of the different crystal sites. Magnitude and orientation of the g tensor of Y(D)(*) and related information on several proton hyperfine tensors are deduced from analysis of angular-dependent EPR spectra. The precise orientation of tyrosine Y(D)(*) in PS II is obtained as a first step in the EPR characterization of paramagnetic species in these single crystals.
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Affiliation(s)
- W Hofbauer
- Max-Volmer-Institut für Biophysikalische Chemie und Biochemie, Technische Universität Berlin, Strasse des 17, Juni 135, D-10623 Berlin, Germany
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32
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Zouni A, Witt HT, Kern J, Fromme P, Krauss N, Saenger W, Orth P. Crystal structure of photosystem II from Synechococcus elongatus at 3.8 A resolution. Nature 2001; 409:739-43. [PMID: 11217865 DOI: 10.1038/35055589] [Citation(s) in RCA: 1643] [Impact Index Per Article: 71.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Oxygenic photosynthesis is the principal energy converter on earth. It is driven by photosystems I and II, two large protein-cofactor complexes located in the thylakoid membrane and acting in series. In photosystem II, water is oxidized; this event provides the overall process with the necessary electrons and protons, and the atmosphere with oxygen. To date, structural information on the architecture of the complex has been provided by electron microscopy of intact, active photosystem II at 15-30 A resolution, and by electron crystallography on two-dimensional crystals of D1-D2-CP47 photosystem II fragments without water oxidizing activity at 8 A resolution. Here we describe the X-ray structure of photosystem II on the basis of crystals fully active in water oxidation. The structure shows how protein subunits and cofactors are spatially organized. The larger subunits are assigned and the locations and orientations of the cofactors are defined. We also provide new information on the position, size and shape of the manganese cluster, which catalyzes water oxidation.
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Affiliation(s)
- A Zouni
- Max-Volmer-Institut für Biophysikalische Chemie und Biochemie, Technische Universität Berlin, Germany
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Linke D, Frank J, Holzwarth JF, Soll J, Boettcher C, Fromme P. In vitro reconstitution and biophysical characterization of OEP16, an outer envelope pore protein of pea chloroplasts. Biochemistry 2000; 39:11050-6. [PMID: 10998242 DOI: 10.1021/bi001034m] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
More than 30% of all proteins in the living cell are membrane proteins; most of them occur in the native membranes only in very low amounts, which hinders their functional and structural investigation. Here we describe the in vitro reconstitution of overexpressed Outer Envelope Protein 16 (OEP16) from pea chloroplasts, a cation-selective channel, which has been purified from E. coli inclusion bodies. Reconstitution in detergent micelles was monitored by CD and fluorescence spectroscopy. Electron microscopy showed a homogeneous size distribution of the reconstituted protein, and differential scanning calorimetry gave an estimate of the enthalpy of protein folding. First protein crystals were obtained that have to be further refined for X-ray structural analysis. The described methods of membrane protein reconstitution and biophysical analysis might prove helpful in the study of other membrane proteins.
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Affiliation(s)
- D Linke
- Max Volmer Institut für Biophysikalische Chemie und Biochemie, Technische Universität Berlin, Strasse des 17, Juni 135, 10623 Berlin, Germany
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Abstract
Oxygen evolution and proton release of crystallised photosystem II core complexes isolated from Synechococcus elongatus were measured. The yields show that the crystals themselves are capable of highly active water oxidation. This opens the possibility for the structural analysis of the outstanding water-oxidising apparatus.
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Affiliation(s)
- A Zouni
- Max-Volmer-Institut für Biophysikalische Chemie und Biochemie, Technische Universität Berlin, Str. d. 17. Juni 135, 10623, Berlin, Germany
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Klukas O, Schubert WD, Jordan P, Krauss N, Fromme P, Witt HT, Saenger W. Photosystem I, an improved model of the stromal subunits PsaC, PsaD, and PsaE. J Biol Chem 1999; 274:7351-60. [PMID: 10066799 DOI: 10.1074/jbc.274.11.7351] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
An improved electron density map of photosystem I (PSI) calculated at 4-A resolution yields a more detailed structural model of the stromal subunits PsaC, PsaD, and PsaE than previously reported. The NMR structure of the subunit PsaE of PSI from Synechococcus sp. PCC7002 (Falzone, C. J., Kao, Y.-H., Zhao, J., Bryant, D. A., and Lecomte, J. T. J. (1994) Biochemistry 33, 6052-6062) has been used as a model to interpret the region of the electron density map corresponding to this subunit. The spatial orientation with respect to other subunits is described as well as the possible interactions between the stromal subunits. A first model of PsaD consisting of a four-stranded beta-sheet and an alpha-helix is suggested, indicating that this subunit partly shields PsaC from the stromal side. In addition to the improvements on the stromal subunits, the structural model of the membrane-integral region of PSI is also extended. The current electron density map allows the identification of the N and C termini of the subunits PsaA and PsaB. The 11-transmembrane alpha-helices of these subunits can now be assigned uniquely to the hydrophobic segments identified by hydrophobicity analyses.
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Affiliation(s)
- O Klukas
- Institut für Kristallographie, Freie Universität Berlin, Takustrassett 6, D-14195 Berlin, Germany
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Klukas O, Schubert WD, Jordan P, Krau N, Fromme P, Witt HT, Saenger W. Localization of two phylloquinones, QK and QK', in an improved electron density map of photosystem I at 4-A resolution. J Biol Chem 1999; 274:7361-7. [PMID: 10066800 DOI: 10.1074/jbc.274.11.7361] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
An improved electron density map of photosystem I from Synechococcus elongatus calculated at 4-A resolution for the first time reveals a second phylloquinone molecule and thereby completes the set of cofactors constituting the electron transfer system of this iron-sulfur type photosynthetic reaction center: six chlorophyll a, two phylloquinones, and three Fe4S4 clusters. The location of the newly identified phylloquinone pair, the individual plane orientations of these molecules, and the resulting distances to other cofactors of the electron transfer system are discussed and compared with those determined by magnetic resonance techniques.
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Affiliation(s)
- O Klukas
- Institut für Kristallographie, Freie Universität Berlin, Takustrasse 6, D-14195 Berlin, Germany
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37
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Schubert WD, Klukas O, Saenger W, Witt HT, Fromme P, Krauss N. A common ancestor for oxygenic and anoxygenic photosynthetic systems: a comparison based on the structural model of photosystem I. J Mol Biol 1998; 280:297-314. [PMID: 9654453 DOI: 10.1006/jmbi.1998.1824] [Citation(s) in RCA: 195] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The 4 A structural model of photosystem I (PSI) has elucidated essential features of this protein complex. Inter alia, it demonstrates that the core proteins of PSI, PsaA and PsaB each consist of an N-terminal antenna-binding domain, and a C-terminal reaction center (RC)-domain. A comparison of the RC-domain of PSI and the photosynthetic RC of purple bacteria (PbRC), reveals significantly analogous structures. This provides the structural support for the hypothesis that the two RC-types (I and II) share a common evolutionary origin. Apart from a similar set of constituent cofactors of the electron transfer system, the analogous features include a comparable cofactor arrangement and a corresponding secondary structure motif of the RC-cores. Despite these analogies, significant differences are evident, particularly as regards the distances between and the orientation of individual cofactors, and the length and orientation of alpha-helices. Inferred roles of conserved amino acids are discussed for PSI, photosystem II (PSII), photosystem C (PSC, green sulfur bacteria) and photosystem H (PSH, heliobacteria). Significant sequence homology between the N-terminal, antenna-binding domains of the core proteins of type-I RCs, PsaA, PsaB, PscA and PshA (of PSI, PSC and PSH respectively) with the antenna-binding subunits CP43 and CP47 of PSII indicate that PSII has a modular structure comparable to that of PSI.
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Affiliation(s)
- W D Schubert
- Institut für Kristallographie, Freie Universität Berlin, Takustr. 6, Berlin, D-14195, Germany
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38
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Schubert WD, Klukas O, Krauss N, Saenger W, Fromme P, Witt HT. Photosystem I of Synechococcus elongatus at 4 A resolution: comprehensive structure analysis. J Mol Biol 1997; 272:741-69. [PMID: 9368655 DOI: 10.1006/jmbi.1997.1269] [Citation(s) in RCA: 224] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
An improved structural model of the photosystem I complex from the thermophilic cyanobacterium Synechococcus elongatus is described at 4 A resolution. This represents the most complete model of a photosystem presently available, uniting both a photosynthetic reaction centre domain and a core antenna system. Most constituent elements of the electron transfer system have been located and their relative centre-to-centre distances determined at an accuracy of approximately 1 A. These include three pseudosymmetric pairs of Chla and three iron-sulphur centres, FX, FA and FB. The first pair, a Chla dimer, has been assigned to the primary electron donor P700. One or both Chla of the second pair, eC2 and eC'2, presumably functionally link P700 to the corresponding Chla of the third pair, eC3 and eC'3, which is assumed to constitute the spectroscopically-identified primary electron acceptor(s), A0, of PSI. A likely location of the subsequent phylloquinone electron acceptor, QK, in relation to the properties of the spectroscopically identified electron acceptor A1 is discussed. The positions of a total of 89 Chla, 83 of which constitute the core antenna system, are presented. The maximal centre-to-centre distance between antenna Chla is < or = 16 A; 81 Chla are grouped into four clusters comprising 21, 23, 17 and 20 Chla, respectively. Two "connecting" Chla are positioned to structurally (and possibly functionally) link the Chla of the core antenna to those of the electron transfer system. Thus the second and third Chla pairs of the electron transfer system may have a dual function both in energy transfer and electron transport. A total of 34 transmembrane and nine surface alpha-helices have been identified and assigned to the 11 subunits of the PSI complex. The connectivity of the nine C-terminal (seven transmembrane, two "surface") alpha-helices of each of the large core subunits PsaA and PsaB is described. The assignment of the amino acid sequence to the transmembrane alpha-helices is proposed and likely residues involved in co-ordinating the Chla of the electron transfer system discussed.
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Affiliation(s)
- W D Schubert
- Institut für Kristallographie, Freie Universität Berlin, Germany
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Bittl R, Zech SG, Fromme P, Witt HT, Lubitz W. Pulsed EPR structure analysis of photosystem I single crystals: localization of the phylloquinone acceptor. Biochemistry 1997; 36:12001-4. [PMID: 9340008 DOI: 10.1021/bi971645n] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A novel application of electron paramagnetic resonance (EPR) is reported to gain three dimensional structural information on cofactors in proteins. The method is applied here to determine the unknown position of the electron acceptor QK, a phylloquinone (vitamin K1), in the electron transfer chain in photosystem I of oxygenic photosynthesis. The unusual electron spin echo (out-of-phase echo) observed for the light induced radical pair P700.+QK.- in PS I allows the measurement of the dipolar coupling between the two radical pair spins which yields directly the distance between these two radicals. Full advantage of the information in the out-of-phase echo modulation can be taken if measurements using single crystals are performed. With such samples, the orientation of the principal axis of the dipolar interaction, i.e., the axis connecting P700.+QK.-, can be determined with respect to the crystal axes system. An angle of theta = (27 +/- 5)degrees between the dipolar coupling axis and the crystallographic c-axis has been derived from the modulation of the out-of-phase echo. Furthermore, the projection of the dipolar axis into the crystallographic a,b-plane, is found to be parallel to the a-axis. The results allow for the determination of two possible locations of QK within the electron transfer chain of photosystem I. These two positions are related to each other by the pseudo C2 symmetry of the chlorophyll cofactors.
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Affiliation(s)
- R Bittl
- Max-Volmer-Institut für Biophysikalische Chemie und Biochemie, Technische Universität Berlin, Germany.
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Kamlowski A, van der Est A, Fromme P, Krauss N, Schubert WD, Klukas O, Stehlik D. The structural organization of the PsaC protein in Photosystem I from single crystal EPR and X-ray crystallographic studies. Biochim Biophys Acta 1997; 1319:199-213. [PMID: 9131044 DOI: 10.1016/s0005-2728(96)00162-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In Photosystem I (PS I) the terminal electron acceptors, FA and FB, are iron-sulfur (4Fe-4S) centers, which are bound to the stromal subunit PsaC. The orientation of PsaC is determined relative to the whole PS I complex (see Schubert, W.-D. et al. (1995) in From Light to Biosphere (Mathis, P. ed.), Vol. II, pp. 3-10, Kluwer) from which a molecular model for the structure of PsaC within PS I is derived. Two strategies are followed: (i) PS I single crystal EPR data on the orientation of the g tensors of both FA- and FB- relative to each other and relative to the crystal axes (see preceding paper) are used in conjunction with the central structural part of the bacterial 2 [Fe4S4] ferredoxins, the cysteine binding motifs of which are known to be homologous to those of PsaC; (ii) the same core structure is fitted into the intermediate resolution electron density map of PS I. The PsaC orientation obtained both ways agree well. The local twofold symmetry axis inherent to the ferredoxin model leaves a twofold ambiguity in the structural conclusion. Deviations from this C2-symmetry in the amino acid sequence of PsaC are analyzed with respect to observable properties which would resolve the remaining structural ambiguity. Arguments both for and against FA being the distal iron-sulfur center (to FX) are discussed.
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Affiliation(s)
- A Kamlowski
- Institut für Experimentalphysik, Freie Universität Berlin, Germany
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van der Est A, Prisner T, Bittl R, Fromme P, Lubitz W, Möbius K, Stehlik D. Time-Resolved X-, K-, and W-Band EPR of the Radical Pair State of Photosystem I in Comparison with in Bacterial Reaction Centers. J Phys Chem B 1997. [DOI: 10.1021/jp9622086] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- A. van der Est
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany, and Max Volmer Institut, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - T. Prisner
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany, and Max Volmer Institut, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - R. Bittl
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany, and Max Volmer Institut, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - P. Fromme
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany, and Max Volmer Institut, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - W. Lubitz
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany, and Max Volmer Institut, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - K. Möbius
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany, and Max Volmer Institut, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - D. Stehlik
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany, and Max Volmer Institut, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
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Krauss N, Schubert WD, Klukas O, Fromme P, Witt HT, Saenger W. Photosystem I at 4 A resolution represents the first structural model of a joint photosynthetic reaction centre and core antenna system. Nat Struct Biol 1996; 3:965-73. [PMID: 8901876 DOI: 10.1038/nsb1196-965] [Citation(s) in RCA: 287] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The 4 A X-ray structure model of trimeric photosystem I of the cyanobacterium Synechococcus elongatus reveals 31 transmembrane, nine surface and three stromal alpha-helices per monomer, assigned to the 11 protein subunits: PsaA and PsaB are related by a pseudo two-fold axis normal to the membrane plane, along which the electron transfer pigments are arranged. 65 antenna chlorophyll a (Chl a) molecules separated by < or = 16 A form an oval, clustered net continuous with the electron transfer chain through the second and third Chl a pairs of the electron transfer system. This suggests a dual role for these Chl a both in excitation energy and electron transfer. The architecture of the protein core indicates quinone and iron-sulphur type reaction centres to have a common ancestor.
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Affiliation(s)
- N Krauss
- Institut für Kristallographie, Freie Universität Berlin, Germany
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Abstract
The past year has been significant advances in the understanding of the structure and function of photosystem I (PS I). The highlights included significant progress in discovering the arrangement and function of subunits of PS I, and improvement of the structure of PS I to 4 degrees resolution, as well as new evidence for the mechanism of the interaction of PS I with its soluble electron carriers plastocyanine, cytochrome c6 and ferredoxin. Substantial progress has been made towards understanding the mechanism of energy transfer from the antenna system to the reaction centre, and the electronic structure of the electron carriers.
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Affiliation(s)
- P Fromme
- Max Volmer Institut für Biophysikalische und Physikalische Chemie, Technische Universität Berlin, Str. des 17. Juni 135, 10623 Berlin, Germany.
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Käβ H, Fromme P, Lubitz W. Quadrupole parameters of nitrogen nuclei in the cation radical P700.+ determined by ESEEM of single crystals of phtosystem I. Chem Phys Lett 1996. [DOI: 10.1016/0009-2614(96)00533-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Kuhn M, Fromme P, Krabben L. A 'membrane attached' alpha-helix: a conserved structural motif in bacterial reaction centres, photosystem I and chloroplast NADH-plastoquinone oxidoreductase. Trends Biochem Sci 1994; 19:401-2. [PMID: 7817394 DOI: 10.1016/0968-0004(94)90085-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- M Kuhn
- TU Berlin, Max Volmer Institut, Germany
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Lüneberg J, Fromme P, Jekow P, Schlodder E. Spectroscopic characterization of PS I core complexes from thermophilic Synechococcus sp. Identical reoxidation kinetics of A1- before and after removal of the iron-sulfur-clusters FA and FB. FEBS Lett 1994; 338:197-202. [PMID: 8307180 DOI: 10.1016/0014-5793(94)80364-1] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Monomeric and trimeric PS I complexes missing the three stromal subunits E,C and D (termed PS I core complexes) were prepared from the thermophilic cyanobacterium Synechococcus sp. by incubation with urea. The subunits E,C and D are sequentially removed. In the monomeric PS I the subunit C is removed with a half life of approx. 5 min. This is about eight times faster than in the trimeric PS I complex. In parallel with the removal of the FA/B containing subunit C the reduction kinetics of P700+ changed from a half life of about 25 ms to about 750 microseconds. The partner of P700+ in the 750 microseconds charge recombination was identified to be FX by the difference spectrum of this phase. There are some minor differences in the spectra of trimeric and monomeric PS I core complexes. At 77K the forward electron transfer from A1- to FX is blocked in the major fraction of the PS I core complexes and P700+ A1- recombines with a half life of about 220 microseconds. In the remaining fraction P700+FX- is formed and decays with a half life of approx. 10 ms at 77 K. The kinetics of the forward electron transfer from A1- to the iron-sulfur-clusters was measured in the native PS I and the corresponding core complexes. The reoxidation kinetics of A1- are identical in both cases (t1/2 = 180 ns). We conclude that FX is an obligatory intermediate in the normal forward electron transfer.
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Affiliation(s)
- J Lüneberg
- Max-Volmer-Institut für Biophysikalische und Physikalische Chemie, Technische Universität Berlin, Germany
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Abstract
Uni-site ATP synthesis was measured with thylakoids. The membrane-bound ATP-synthase, CF0F1, was brought into the active, reduced state by illumination in the presence of thioredoxin, dithiothreitol and phosphate. This enzyme contains two tightly bound ATP per CF0F1. ATP was released from the enzyme when ADP was added in substoichiometric amounts during illumination. Experiments with [14C]ADP indicated that after binding the same nucleotide was phosphorylated and released as [14C]ATP, i.e. only one site is involved in ATP-synthesis ('uni-site ATP-synthesis'). The two tightly bound ATP are not involved in the catalytic turnover. The rate constant for ADP binding was (4 +/- 2) x 10(6) M-1s-1. Compared to deenergized conditions the rate constant for ADP binding and that for ATP-release were drastically increased, i.e. membrane energization increased the rate constants for the ATP-synthesis direction.
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Affiliation(s)
- A Labahn
- Max Volmer Institut für Biophysikalische und Physikalische Chemie, Technische Universität Berlin, FRG
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Abstract
ATP-hydrolysis was measured with thylakoid membranes during continuous illumination. The concentrations of free and enzyme-bound ATP, ADP and Pi were measured using either cold ATP, [gamma-32P]ATP or [14C]ATP. The concentration of free ATP was constant, free ADP and enzyme-bound ATP were below the detection limit. Nevertheless, [gamma-32P]ATP was bound, hydrolyzed and 32Pi was released. The ADP was not released from the enzyme but cold Pi was bound from the medium, cold ATP was resynthesized and released. A quantitative analysis gave the following rate constants: ATP-binding kATP = 2 . 10(5) M-1 s-1, ADP-release: kADP less than 10(-2)s-1, Pi-release: kPi = 0.1 s-1. These rate constants are considerably smaller than under deenergized conditions. The rate constant for the release of ATP can be estimated to be at least 0.2 s-1 under energized conditions. Obviously, energization of the membrane, i.e. protonation of the enzyme leads mainly to a decrease of the rate of ATP-binding, to an increase of the rate of ATP release and to a decrease of the rate of ADP-release.
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Affiliation(s)
- P Fromme
- Max Volmer Institut für Biophysikalische und Physikalische Chemie, Technische Universität Berlin, FRG
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Abstract
The proton-translocating ATP-synthase of chloroplasts, CF0F1, was isolated and reconstituted into asolectin liposomes. CF0F1 can exist in at least four different states, oxidized or reduced, either inactive or active. These states are characterized by different kinetics of ADP binding: There is no binding of ADP to the inactive, oxidized state, the rate constant for ADP binding to the inactive, reduced states is 7.10(2) M-1.s-1. ADP binding to the active, reduced state occurs under deenergized conditions with 10(5) M-1.s-1 and transforms the enzyme into the inactive, reduced state. Parallel to the ADP-dependent inactivation, the enzyme can also inactivate without ADP binding with a first-order rate constant of 7.10(-3) M-1.s-1. With the active, reduced enzyme ATP-hydrolysis was measured under uni-site conditions as has been carried out with MF1 (Grubmeyer, C., Cross, R.C. and Penefsky, H.S. (1982) J. Biol. Chem. 257, 12092-12100). The rate constant for ATP binding is 10(6) M-1.s-1, the 'equilibrium constant' on the enzyme EADPPi/EATP is 0.4. The rate constants for Pi release and ADP release are 0.2 s-1 and o.1 s-1, respectively. This indicates that the enzyme carries out a complete turnover under uni-site conditions with rates much higher than that reported for MF1.
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Affiliation(s)
- P Fromme
- Max-Volmer-Institut für Biophysikalische und Physikalische Chemie, Technische Universität Berlin (Germany)
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