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Yano J, Kern J, Yachandra VK, Nilsson H, Koroidov S, Messinger J. Light-dependent production of dioxygen in photosynthesis. Met Ions Life Sci 2015; 15:13-43. [PMID: 25707465 PMCID: PMC4688042 DOI: 10.1007/978-3-319-12415-5_2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Oxygen, that supports all aerobic life, is abundant in the atmosphere because of its constant regeneration by photosynthetic water oxidation, which is catalyzed by a Mn₄CaO₅ cluster in photosystem II (PS II), a multi subunit membrane protein complex. X-ray and other spectroscopy studies of the electronic and geometric structure of the Mn₄CaO₅ cluster as it advances through the intermediate states have been important for understanding the mechanism of water oxidation. The results and interpretations, especially from X-ray spectroscopy studies, regarding the geometric and electronic structure and the changes as the system proceeds through the catalytic cycle will be summarized in this review. This review will also include newer methodologies in time-resolved X-ray diffraction and spectroscopy that have become available since the commissioning of the X-ray free electron laser (XFEL) and are being applied to study the oxygen-evolving complex (OEC). The femtosecond X-ray pulses of the XFEL allows us to outrun X-ray damage at room temperature, and the time-evolution of the photo-induced reaction can be probed using a visible laser-pump followed by the X-ray-probe pulse. XFELs can be used to simultaneously determine the light-induced protein dynamics using crystallography and the local chemistry that occurs at the catalytic center using X-ray spectroscopy under functional conditions. Membrane inlet mass spectrometry has been important for providing direct information about the exchange of substrate water molecules, which has a direct bearing on the mechanism of water oxidation. Moreover, it has been indispensable for the time-resolved X-ray diffraction and spectroscopy studies and will be briefly reviewed in this chapter. Given the role of PS II in maintaining life in the biosphere and the future vision of a renewable energy economy, understanding the structure and mechanism of the photosynthetic water oxidation catalyst is an important goal for the future.
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Lorenz K, Sekulla C, Kern J, Dralle H. Management von Nachblutungen nach Schilddrüsenoperationen. Chirurg 2014; 86:17-23. [DOI: 10.1007/s00104-014-2818-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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103
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Badel T, Kes VB, Rosic D, Zadravec D, Kern J. EHMTI-0275. Headache and cervical spine disturbances in a patient with osteoarthritis of temporomandibular joint – one-year-follow-up. J Headache Pain 2014. [PMCID: PMC4180156 DOI: 10.1186/1129-2377-15-s1-c5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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104
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Hellmich J, Bommer M, Burkhardt A, Ibrahim M, Kern J, Meents A, Müh F, Dobbek H, Zouni A. Native-like Photosystem II Superstructure at 2.44 Å Resolution through Detergent Extraction from the Protein Crystal. Structure 2014; 22:1607-15. [DOI: 10.1016/j.str.2014.09.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 08/26/2014] [Accepted: 09/10/2014] [Indexed: 10/24/2022]
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105
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Kern J, Tran R, Chatterjee R, Han G, Alonso-Mori R, Bergmann U, Yachandra V, Yano J. Water Oxidation in Natural Photosynthesis. Acta Crystallogr A Found Adv 2014. [DOI: 10.1107/s2053273314092766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The photosynthetic water oxidation reaction is energetically demanding and mechanistically complex because of the difficulties in managing the four electron, four proton redox chemistry required for the evolution of molecular oxygen starting from two water molecules. The reaction takes place in Photosystem II (PS II), a multi-subunit membrane protein present in plants, algae, and cyanobacteria. This sunlight-driven reaction is catalyzed by an oxygen-evolving complex (OEC), that consists of an oxo-bridged four Mn and one Ca cluster. O2 is formed and released only after four oxidation equivalents are accumulated at the OEC. The structure of the Mn4CaO5 cluster has been studied by various spectroscopic and diffraction methods. The recent XRD study by Umena et al.[1] has shown the oxo-bridged Mn4Ca cluster structure at 1.9 Å resolution. Based on this high-resolution XRD structure, there have been efforts to obtain chemically optimized structures and structural changes of the Mn4CaO5 cluster during the catalytic cycle using spectroscopic parameters and theoretical approaches. EXAFS spectra of the PS II S states show that the structure of the Mn4CaO5 cluster changes during the catalytic cycle.[2] In particular, the short Mn-Mn distances change in the range of 2.7 to 2.9 Å. Such changes in oxygen-bridged Mn-Mn distances can reflect several chemical parameters; Mn oxidation state changes, protonation state changes of bridging oxygens, ligation modes (e.g. bidentate/monodentate), as well as fundamental changes in geometry. We have also used femtosecond X-ray spectroscopy and crystallography to study the catalytic process of the OEC.[3] The femtosecond X-ray pulses of the free-electron laser allows us to out-run X-ray damage at room temperature, and the time-evolution of the photo-induced reaction can be probed using a visible laser-pump followed by the X-ray-probe pulse. We will discuss a possible water oxidation mechanism based on these results.
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Sauter N, Brewster A, Hattne J, Amin M, Kern J, Yano J, Yachandra V. Improving the accuracy for Photosystem II and other XFEL structures. Acta Crystallogr A Found Adv 2014. [DOI: 10.1107/s2053273314094285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Femtosecond-scale XFEL pulses can produce diffraction free from radiation damage, under functional physiological conditions where reaction dynamics can be studied for systems such as photosystem II. However, it has been extremely difficult to derive accurate structure factors from the data since every shot is a still exposure from a distinct specimen. Accuracy can be improved by software methods implemented in the program cctbx.xfel, including optimal indexing and retention of data from multiple lattices, and separate determination of the resolution cutoff for individual lattices. Various techniques can produce well-conforming descriptions of the Bragg spot shape and crystal mosaicity, enabled in part by sub-pixel characterization of the detector geometry. By carefully discriminating between image pixels known to contain diffraction signal and the surrounding pixels containing only background noise, and by extending postrefinement techniques that lead to a better crystal orientation, we derive accurate structure factors with substantially fewer crystal specimen exposures. It is hoped that these developments will make it easier to measure small structure factor differences, such as those from anomalous scattering that will enable the de novo determination of macromolecular structure.
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Kern J, Tran R, Alonso-Mori R, Koroidov S, Echols N, Hattne J, Ibrahim M, Gul S, Laksmono H, Sierra RG, Gildea RJ, Han G, Hellmich J, Lassalle-Kaiser B, Chatterjee R, Brewster AS, Stan CA, Glöckner C, Lampe A, DiFiore D, Milathianaki D, Fry AR, Seibert MM, Koglin JE, Gallo E, Uhlig J, Sokaras D, Weng TC, Zwart PH, Skinner DE, Bogan MJ, Messerschmidt M, Glatzel P, Williams GJ, Boutet S, Adams PD, Zouni A, Messinger J, Sauter NK, Bergmann U, Yano J, Yachandra VK. Taking snapshots of photosynthetic water oxidation using femtosecond X-ray diffraction and spectroscopy. Nat Commun 2014; 5:4371. [PMID: 25006873 PMCID: PMC4151126 DOI: 10.1038/ncomms5371] [Citation(s) in RCA: 161] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 06/10/2014] [Indexed: 01/07/2023] Open
Abstract
The dioxygen we breathe is formed by light-induced oxidation of water in photosystem II. O2 formation takes place at a catalytic manganese cluster within milliseconds after the photosystem II reaction centre is excited by three single-turnover flashes. Here we present combined X-ray emission spectra and diffraction data of 2-flash (2F) and 3-flash (3F) photosystem II samples, and of a transient 3F' state (250 μs after the third flash), collected under functional conditions using an X-ray free electron laser. The spectra show that the initial O-O bond formation, coupled to Mn reduction, does not yet occur within 250 μs after the third flash. Diffraction data of all states studied exhibit an anomalous scattering signal from Mn but show no significant structural changes at the present resolution of 4.5 Å. This study represents the initial frames in a molecular movie of the structural changes during the catalytic reaction in photosystem II.
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Hattne J, Echols N, Tran R, Kern J, Gildea RJ, Brewster AS, Alonso-Mori R, Glöckner C, Hellmich J, Laksmono H, Sierra RG, Lassalle-Kaiser B, Lampe A, Han G, Gul S, DiFiore D, Milathianaki D, Fry AR, Miahnahri A, White WE, Schafer DW, Seibert MM, Koglin JE, Sokaras D, Weng TC, Sellberg J, Latimer MJ, Glatzel P, Zwart PH, Grosse-Kunstleve RW, Bogan MJ, Messerschmidt M, Williams GJ, Boutet S, Messinger J, Zouni A, Yano J, Bergmann U, Yachandra VK, Adams PD, Sauter NK. Accurate macromolecular structures using minimal measurements from X-ray free-electron lasers. Nat Methods 2014; 11:545-8. [PMID: 24633409 DOI: 10.1038/nmeth.2887] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2013] [Accepted: 02/04/2014] [Indexed: 01/19/2023]
Abstract
X-ray free-electron laser (XFEL) sources enable the use of crystallography to solve three-dimensional macromolecular structures under native conditions and without radiation damage. Results to date, however, have been limited by the challenge of deriving accurate Bragg intensities from a heterogeneous population of microcrystals, while at the same time modeling the X-ray spectrum and detector geometry. Here we present a computational approach designed to extract meaningful high-resolution signals from fewer diffraction measurements.
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Fichter T, Trieb F, Moser M, Kern J. Optimized Integration of Renewable Energies into Existing Power Plant Portfolios. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/j.egypro.2014.03.197] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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110
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Krewald V, Lassalle-Kaiser B, Boron TT, Pollock CJ, Kern J, Beckwith MA, Yachandra VK, Pecoraro VL, Yano J, Neese F, DeBeer S. The protonation states of oxo-bridged Mn(IV) dimers resolved by experimental and computational Mn K pre-edge X-ray absorption spectroscopy. Inorg Chem 2013; 52:12904-14. [PMID: 24161030 PMCID: PMC3911776 DOI: 10.1021/ic4008203] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In nature, the protonation of oxo bridges is a commonly encountered mechanism for fine-tuning chemical properties and reaction pathways. Often, however, the protonation states are difficult to establish experimentally. This is of particular importance in the oxygen evolving complex of photosystem II, where identification of the bridging oxo protonation states is one of the essential requirements toward unraveling the mechanism. In order to establish a combined experimental and theoretical protocol for the determination of protonation states, we have systematically investigated a series of Mn model complexes by Mn K pre-edge X-ray absorption spectroscopy. An ideal test case for selective bis-μ-oxo-bridge protonation in a Mn dimer is represented by the system [Mn(IV)2(salpn)2(μ-OHn)2](n+). Although the three species [Mn(IV)2(salpn)2(μ-O)2], [Mn(IV)2(salpn)2(μ-O)(μ-OH)](+) and [Mn(IV)2(salpn)2(μ-OH)2](2+) differ only in the protonation of the oxo bridges, they exhibit distinct differences in the pre-edge region while maintaining the same edge energy. The experimental spectra are correlated in detail to theoretically calculated spectra. A time-dependent density functional theory approach for calculating the pre-edge spectra of molecules with multiple metal centers is presented, using both high spin (HS) and broken symmetry (BS) electronic structure solutions. The most intense pre-edge transitions correspond to an excitation of the Mn 1s core electrons into the unoccupied orbitals of local e(g) character (d(z)(2) and d(xy) based in the chosen coordinate system). The lowest energy experimental feature is dominated by excitations of 1s-α electrons, and the second observed feature is primarily attributed to 1s-β electron excitations. The observed energetic separation is due to spin polarization effects in spin-unrestricted density functional theory and models final state multiplet effects. The effects of spin polarization on the calculated Mn K pre-edge spectra, in both the HS and BS solutions, are discussed in terms of the strength of the antiferromagnetic coupling and associated changes in the covalency of Mn-O bonds. The information presented in this paper is complemented with the X-ray emission spectra of the same compounds published in an accompanying paper. Taken together, the two studies provide the foundation for a better understanding of the X-ray spectroscopic data of the oxygen evolving complex (OEC) in photosystem II.
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Lassalle-Kaiser B, Boron TT, Krewald V, Kern J, Beckwith MA, Schroeder H, Alonso-Mori R, Nordlund D, Weng TC, Sokaras D, Neese F, Bergmann U, Yachandra VK, DeBeer S, Pecoraro VL, Yano J. Experimental and computational X-ray emission spectroscopy as a direct probe of protonation states in oxo-bridged Mn(IV) dimers relevant to redox-active metalloproteins. Inorg Chem 2013; 52:12915-22. [PMID: 24161081 PMCID: PMC3867288 DOI: 10.1021/ic400821g] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The protonation state of oxo bridges in nature is of profound importance for a variety of enzymes, including the Mn4CaO5 cluster of photosystem II and the Mn2O2 cluster in Mn catalase. A set of dinuclear bis-μ-oxo-bridged Mn(IV) complexes in different protonation states was studied by Kβ emission spectroscopy to form the foundation for unraveling the protonation states in the native complex. The valence-to-core regions (valence-to-core XES) of the spectra show significant changes in intensity and peak position upon protonation. DFT calculations were performed to simulate the valence-to-core XES spectra and to assign the spectral features to specific transitions. The Kβ(2,5) peaks arise primarily from the ligand 2p to Mn 1s transitions, with a characteristic low energy shoulder appearing upon oxo-bridge protonation. The satellite Kβ" peak provides a more direct signature of the protonation state change, since the transitions originating from the 2s orbitals of protonated and unprotonated μ-oxo bridges dominate this spectral region. The energies of the Kβ" features differ by ~3 eV and thus are well resolved in the experimental spectra. Additionally, our work explores the chemical resolution limits of the method, namely, whether a mixed (μ-O)(μ-OH2) motif can be distinguished from a symmetric (μ-OH)2 one. The results reported here highlight the sensitivity of Kβ valence-to-core XES to single protonation state changes of bridging ligands, and form the basis for further studies of oxo-bridged polymetallic complexes and metalloenzyme active sites. In a complementary paper, the results from X-ray absorption spectroscopy of the same Mn(IV) dimer series are discussed.
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112
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Gottschlich A, Hoffmann J, Kern J, Stepan H. Präeklampsie vs. chronische Nierenerkrankung – Differentialdiagnose mittels sFlt-1/PlGF-Ratio. Z Geburtshilfe Neonatol 2013. [DOI: 10.1055/s-0033-1361382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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113
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Bornmann K, Kern J, Bläser A, Stepan H. Floride maternale Varizelleninfektion in Terminnähe. Z Geburtshilfe Neonatol 2013. [DOI: 10.1055/s-0033-1361244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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114
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Gottschlich A, Stepan H, Thome U, Kern J, Faber R. Spontane monochoriale – quadramniale Vierlingsschwangerschaft – ein Fallbericht. Z Geburtshilfe Neonatol 2013. [DOI: 10.1055/s-0033-1361463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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115
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Mitzner R, Rehanek J, Kern J, Gul S, Hattne J, Taguchi T, Alonso-Mori R, Tran R, Weniger C, Schröder H, Quevedo W, Laksmono H, Sierra RG, Han G, Lassalle-Kaiser B, Koroidov S, Kubicek K, Schreck S, Kunnus K, Brzhezinskaya M, Firsov A, Minitti MP, Turner JJ, Moeller S, Sauter NK, Bogan MJ, Nordlund D, Schlotter WF, Messinger J, Borovik A, Techert S, de Groot FMF, Föhlisch A, Erko A, Bergmann U, Yachandra VK, Wernet P, Yano J. L-Edge X-ray Absorption Spectroscopy of Dilute Systems Relevant to Metalloproteins Using an X-ray Free-Electron Laser. J Phys Chem Lett 2013; 4:3641-3647. [PMID: 24466387 PMCID: PMC3901369 DOI: 10.1021/jz401837f] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
L-edge spectroscopy of 3d transition metals provides important electronic structure information and has been used in many fields. However, the use of this method for studying dilute aqueous systems, such as metalloenzymes, has not been prevalent because of severe radiation damage and the lack of suitable detection systems. Here we present spectra from a dilute Mn aqueous solution using a high-transmission zone-plate spectrometer at the Linac Coherent Light Source (LCLS). The spectrometer has been optimized for discriminating the Mn L-edge signal from the overwhelming O K-edge background that arises from water and protein itself, and the ultrashort LCLS X-ray pulses can outrun X-ray induced damage. We show that the deviations of the partial-fluorescence yield-detected spectra from the true absorption can be well modeled using the state-dependence of the fluorescence yield, and discuss implications for the application of our concept to biological samples.
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116
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Kern J, Bolten D, Simonato S, Feldmann C, Staudt R, Türk M, Johannsen M. Nanoskalige Trägermaterialien zur Adsorption von Enantiomeren. CHEM-ING-TECH 2013. [DOI: 10.1002/cite.201250707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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117
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Ballew C, Benton E, Groves D, Kennedy J, Bergin J, Ailawadi G, Kern J. Comparing Survival of HMII Patients with Elevated LDH Levels: Implications for Medical and Surgical Management. Heart Lung 2013. [DOI: 10.1016/j.hrtlng.2013.06.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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118
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Glöckner C, Kern J, Broser M, Zouni A, Yachandra V, Yano J. Structural changes of the oxygen-evolving complex in photosystem II during the catalytic cycle. J Biol Chem 2013; 288:22607-20. [PMID: 23766513 DOI: 10.1074/jbc.m113.476622] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The oxygen-evolving complex (OEC) in the membrane-bound protein complex photosystem II (PSII) catalyzes the water oxidation reaction that takes place in oxygenic photosynthetic organisms. We investigated the structural changes of the Mn4CaO5 cluster in the OEC during the S state transitions using x-ray absorption spectroscopy (XAS). Overall structural changes of the Mn4CaO5 cluster, based on the manganese ligand and Mn-Mn distances obtained from this study, were incorporated into the geometry of the Mn4CaO5 cluster in the OEC obtained from a polarized XAS model and the 1.9-Å high resolution crystal structure. Additionally, we compared the S1 state XAS of the dimeric and monomeric form of PSII from Thermosynechococcus elongatus and spinach PSII. Although the basic structures of the OEC are the same for T. elongatus PSII and spinach PSII, minor electronic structural differences that affect the manganese K-edge XAS between T. elongatus PSII and spinach PSII are found and may originate from differences in the second sphere ligand atom geometry.
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119
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Gottschlich A, Kern J, Stepan H. Differentialdiagnose Präeklampsie vs. chronische Nierenerkrankung mittels sFlt-1/PlGF-Ratio am Beispiel zweier klinischer Fälle. Geburtshilfe Frauenheilkd 2013. [DOI: 10.1055/s-0033-1347748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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120
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Bornmann K, Kern J, Bläser A, Stepan H. Floride maternale Varizelleninfektion in Terminnähe. Geburtshilfe Frauenheilkd 2013. [DOI: 10.1055/s-0033-1343549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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121
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Schrey S, Kern J, Thome U, Stepan H. Hypoplastisches Rechtsherzsyndrom des Rezipienten trotz erfolgreicher Laser-Therapie bei Feto-Fetalem-Transfusions-Syndrom. Geburtshilfe Frauenheilkd 2013. [DOI: 10.1055/s-0033-1343541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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122
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Kreutmayer S, Csordas A, Kern J, Maass V, Almanzar G, Offterdinger M, Öllinger R, Maass M, Wick G. Chlamydia pneumoniae infection acts as an endothelial stressor with the potential to initiate the earliest heat shock protein 60-dependent inflammatory stage of atherosclerosis. Cell Stress Chaperones 2013; 18:259-68. [PMID: 23192457 PMCID: PMC3631098 DOI: 10.1007/s12192-012-0378-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2012] [Revised: 10/01/2012] [Accepted: 10/02/2012] [Indexed: 12/21/2022] Open
Abstract
We identified increased expression and redistribution of the intracellular protein 60-kDa human heat shock protein (hHSP60) (HSPD1) to the cell surface in human endothelial cells subjected to classical atherosclerosis risk factors and subsequent immunologic cross-reactivity against this highly conserved molecule, as key events occurring early in the process of atherosclerosis. The present study aimed at investigating the role of infectious pathogens as stress factors for vascular endothelial cells and, as such, contributors to early atherosclerotic lesion formation. Using primary donor-matched arterial and venous human endothelial cells, we show that infection with Chlamydia pneumoniae leads to marked upregulation and surface expression of hHSP60 and adhesion molecules. Moreover, we provide evidence for an increased susceptibility of arterial endothelial cells for redistribution of hHSP60 to the cellular membrane in response to C. pneumoniae infection as compared to autologous venous endothelial cells. We also show that oxidative stress has a central role to play in endothelial cell activation in response to chlamydial infection. These data provide evidence for a role of C. pneumoniae as a potent primary endothelial stressor for arterial endothelial cells leading to enrichment of hHSP60 on the cellular membrane and, as such, a potential initiator of atherosclerosis.
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123
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Kern J, Alonso-Mori R, Tran R, Hattne J, Gildea RJ, Echols N, Glöckner C, Hellmich J, Laksmono H, Sierra RG, Lassalle-Kaiser B, Koroidov S, Lampe A, Han G, Gul S, DiFiore D, Milathianaki D, Fry AR, Miahnahri A, Schafer DW, Messerschmidt M, Seibert MM, Koglin JE, Sokaras D, Weng TC, Sellberg J, Latimer MJ, Grosse-Kunstleve RW, Zwart PH, White WE, Glatzel P, Adams PD, Bogan MJ, Williams GJ, Boutet S, Messinger J, Zouni A, Sauter NK, Yachandra VK, Bergmann U, Yano J. Simultaneous femtosecond X-ray spectroscopy and diffraction of photosystem II at room temperature. Science 2013; 340:491-5. [PMID: 23413188 PMCID: PMC3732582 DOI: 10.1126/science.1234273] [Citation(s) in RCA: 303] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Intense femtosecond x-ray pulses produced at the Linac Coherent Light Source (LCLS) were used for simultaneous x-ray diffraction (XRD) and x-ray emission spectroscopy (XES) of microcrystals of photosystem II (PS II) at room temperature. This method probes the overall protein structure and the electronic structure of the Mn4CaO5 cluster in the oxygen-evolving complex of PS II. XRD data are presented from both the dark state (S1) and the first illuminated state (S2) of PS II. Our simultaneous XRD-XES study shows that the PS II crystals are intact during our measurements at the LCLS, not only with respect to the structure of PS II, but also with regard to the electronic structure of the highly radiation-sensitive Mn4CaO5 cluster, opening new directions for future dynamics studies.
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124
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Chamberlain JW, Kern J, Vestine EH. Some consequences of local acceleration of auroral primaries. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jz065i008p02535] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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125
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Sierra RG, Laksmono H, Kern J, Tran R, Hattne J, Alonso-Mori R, Lassalle-Kaiser B, Glöckner C, Hellmich J, Schafer DW, Echols N, Gildea RJ, Grosse-Kunstleve RW, Sellberg J, McQueen TA, Fry AR, Messerschmidt MM, Miahnahri A, Seibert MM, Hampton CY, Starodub D, Loh ND, Sokaras D, Weng TC, Zwart PH, Glatzel P, Milathianaki D, White WE, Adams PD, Williams GJ, Boutet S, Zouni A, Messinger J, Sauter NK, Bergmann U, Yano J, Yachandra VK, Bogan MJ. Nanoflow electrospinning serial femtosecond crystallography. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2012; 68:1584-7. [PMID: 23090408 PMCID: PMC3478121 DOI: 10.1107/s0907444912038152] [Citation(s) in RCA: 153] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 09/05/2012] [Indexed: 11/10/2022]
Abstract
An electrospun liquid microjet has been developed that delivers protein microcrystal suspensions at flow rates of 0.14-3.1 µl min(-1) to perform serial femtosecond crystallography (SFX) studies with X-ray lasers. Thermolysin microcrystals flowed at 0.17 µl min(-1) and diffracted to beyond 4 Å resolution, producing 14,000 indexable diffraction patterns, or four per second, from 140 µg of protein. Nanoflow electrospinning extends SFX to biological samples that necessitate minimal sample consumption.
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