title: Taking snapshots of photosynthetic water oxidation using femtosecond X-ray diffraction and spectroscopy.
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.
authors.affiliation: 1] Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA [2] LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Jan
authors.initials: J
authors.lastname: Kern
authors.affiliation: Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Rosalie
authors.initials: R
authors.lastname: Tran
authors.affiliation: LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Roberto
authors.initials: R
authors.lastname: Alonso-Mori
authors.affiliation: Institutionen för Kemi, Kemiskt Biologiskt Centrum, Umeå Universitet, 90187 Umeå, Sweden.
authors.forename: Sergey
authors.initials: S
authors.lastname: Koroidov
authors.affiliation: Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Nathaniel
authors.initials: N
authors.lastname: Echols
authors.affiliation: Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Johan
authors.initials: J
authors.lastname: Hattne
authors.affiliation: 1] Institut für Biologie, Humboldt-Universität zu Berlin, D-10099 Berlin, Germany [2] Max-Volmer-Laboratorium für Biophysikalische Chemie, Technische Universität, D-10623 Berlin, Germany.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Ibrahim
authors.affiliation: Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Sheraz
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authors.lastname: Gul
authors.affiliation: PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Hartawan
authors.initials: H
authors.lastname: Laksmono
authors.affiliation: PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Raymond G
authors.initials: RG
authors.lastname: Sierra
authors.affiliation: 1] Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA [2].
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Gildea
authors.affiliation: Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Guangye
authors.initials: G
authors.lastname: Han
authors.affiliation: 1] Institut für Biologie, Humboldt-Universität zu Berlin, D-10099 Berlin, Germany [2] Max-Volmer-Laboratorium für Biophysikalische Chemie, Technische Universität, D-10623 Berlin, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Hellmich
authors.affiliation: 1] Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA [2].
authors.forename: Benedikt
authors.initials: B
authors.lastname: Lassalle-Kaiser
authors.affiliation: Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Ruchira
authors.initials: R
authors.lastname: Chatterjee
authors.affiliation: Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Aaron S
authors.initials: AS
authors.lastname: Brewster
authors.affiliation: PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Claudiu A
authors.initials: CA
authors.lastname: Stan
authors.affiliation: Max-Volmer-Laboratorium für Biophysikalische Chemie, Technische Universität, D-10623 Berlin, Germany.
authors.forename: Carina
authors.initials: C
authors.lastname: Glöckner
authors.affiliation: Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Alyssa
authors.initials: A
authors.lastname: Lampe
authors.affiliation: Max-Volmer-Laboratorium für Biophysikalische Chemie, Technische Universität, D-10623 Berlin, Germany.
authors.forename: Dörte
authors.initials: D
authors.lastname: DiFiore
authors.affiliation: LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Despina
authors.initials: D
authors.lastname: Milathianaki
authors.affiliation: LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Alan R
authors.initials: AR
authors.lastname: Fry
authors.affiliation: 1] LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA [2].
authors.forename: M Marvin
authors.initials: MM
authors.lastname: Seibert
authors.affiliation: LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Jason E
authors.initials: JE
authors.lastname: Koglin
authors.affiliation: European Synchrotron Radiation Facility, F-38043 Grenoble, France.
authors.forename: Erik
authors.initials: E
authors.lastname: Gallo
authors.affiliation: European Synchrotron Radiation Facility, F-38043 Grenoble, France.
authors.forename: Jens
authors.initials: J
authors.lastname: Uhlig
authors.affiliation: SSRL, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Dimosthenis
authors.initials: D
authors.lastname: Sokaras
authors.affiliation: SSRL, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Tsu-Chien
authors.initials: TC
authors.lastname: Weng
authors.affiliation: Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Petrus H
authors.initials: PH
authors.lastname: Zwart
authors.affiliation: National Energy Research Scientific Computing Center, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: David E
authors.initials: DE
authors.lastname: Skinner
authors.affiliation: 1] LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA [2] PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Bogan
authors.affiliation: LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Marc
authors.initials: M
authors.lastname: Messerschmidt
authors.affiliation: European Synchrotron Radiation Facility, F-38043 Grenoble, France.
authors.forename: Pieter
authors.initials: P
authors.lastname: Glatzel
authors.affiliation: LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Garth J
authors.initials: GJ
authors.lastname: Williams
authors.affiliation: LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Boutet
authors.affiliation: Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Adams
authors.affiliation: 1] Institut für Biologie, Humboldt-Universität zu Berlin, D-10099 Berlin, Germany [2] Max-Volmer-Laboratorium für Biophysikalische Chemie, Technische Universität, D-10623 Berlin, Germany.
authors.forename: Athina
authors.initials: A
authors.lastname: Zouni
authors.affiliation: Institutionen för Kemi, Kemiskt Biologiskt Centrum, Umeå Universitet, 90187 Umeå, Sweden.
authors.forename: Johannes
authors.initials: J
authors.lastname: Messinger
authors.affiliation: Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Nicholas K
authors.initials: NK
authors.lastname: Sauter
authors.affiliation: LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Uwe
authors.initials: U
authors.lastname: Bergmann
authors.affiliation: Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Junko
authors.initials: J
authors.lastname: Yano
authors.affiliation: Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Vittal K
authors.initials: VK
authors.lastname: Yachandra
mesh_terms: D000458:Cyanobacteria / Q000378:metabolism; D008956:Models, Chemical; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D010788:Photosynthesis / Q000502:physiology*; D045332:Photosystem II Protein Complex / Q000737:chemistry / Q000378:metabolism; D013052:Spectrometry, X-Ray Emission / Q000379:methods*; D014867:Water / Q000378:metabolism*; D014961:X-Ray Diffraction / Q000379:methods*
chemical_list: D045332:Photosystem II Protein Complex; D014867:Water; D010100:Oxygen