(P7A-1) Study on the relationship between structure of photosynthetic oxygenic extrinsic proteins and their physiological functions. (Abstract 347)
Jun Weng¹, Chunhe Xu^*,1, Kangcheng Ruan², ¹ Institute of Plant Physiology, Shanghai Institutes for Biological Science, Chinese Academy of Sciences (CAS), Shanghai, China² Labotatory of Proteomics, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Science, CAS, Shanghai, China

(P7A-2) Flash-number dependent oscillation of the light-induced (at 5 K) split EPR signals from OEC. (Abstract 348)
Jihu Su^*,1, Kajsa Sigfridsson^*,1, Yashar Feyziyev ^*,1,2, Stenbjörn Styring^*,1, ¹ Molecular Biomimetics, Uppsala University, Villavägen 6, 752 36 Uppsala, Sweden² Molecular Biomimetics, Uppsala University, Villavägen 6, 752 36 Uppsala, Sweden

(P7A-3) Reconstitution of the water-oxidizing complex in manganese-depleted Photosystem II complexes by using synthetic manganese complexes. (Abstract 349)
Shuqin Li^*,1, Guangye Han², Guiying Chen³, Qiutian Liu⁴, Liangbi Li⁵, Tingyun Kuang⁶, ¹ 20 Nanxincun, Xiangshan, Haidian District, Institute of Botany, The Chinese Academy of Sciences, Beijing 100093, China, China² 20 Nanxincun, Xiangshan, Haidian District, Institute of Botany, The Chinese Academy of Sciences, Beijing 100093, China, China³ 20 Nanxincun, Xiangshan, Haidian District, Institute of Botany, The Chinese Academy of Sciences, Beijing 100093, China, China⁴ State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Scienc, China⁵ 20 Nanxincun, Xiangshan, Haidian District, Institute of Botany, The Chinese Academy of Sciences, Beijing 100093, China, China⁶ 20 Nanxincun, Xiangshan, Haidian District, Institute of Botany, The Chinese Academy of Sciences, Beijing 100093, China, China

(P7A-4) Studies of the S₀ state multiline signal of the oxygen evolving centre in Photosystem II. (Abstract 350)
Karin Ahrling^*,1, M.C.W. Evans², ¹ Photobioenergetics, Research School of Biological Sciences, Canberra, ACT, Australia² Biology Department, University College London, London, United Kingdom

(P7A-5) Fast repetition rate laser fluorometer and role for bicarbonate in oxygen evolution by Photosystem II at site arginine 357 of CP43. (Abstract 351)
Gennady Ananyev^*,1, Tuan Nguen¹, Rogier Willigen¹, Cindy Putnam-Evans², G. Dismukes¹, ¹ Princeton University, Princeton, NJ, USA² East Carolina University, Greenville, NC, USA

(P7A-6) Pulsed EPR studies of the Mn and tyrosines centers of PSII. (Abstract 352)
R David Britt^*,1, ¹ Department of Chemistry, Davis, CA, USA

(P7A-7) Ammonia-induced structural changes of the oxygen-evolving complex in Photosystem II as revealed by FTIR. (Abstract 353)
Hsiu-An Chu^*,1, ¹ Institute of Botany, Academia Sinica, Taipei, Taiwan, Taiwan

(P7A-8) Water oxidation by PSII - relaxation of the potential of the tyrosine-z radical prior to the oxygen-formation step analyzed by delayed fluorescence measurements. (Abstract 354)
Markus Grabolle, Holger Dau^*,1, ¹ Free Univ. Berlin, D-14185 Berlin, Germany

(P7A-9) Possible mechanisms for photosynthetic O₂ formation based on the higher resolution crystal structure, synthetic complexes and time-dependent electronic structure calculations. (Abstract 355)
Rogier van Willigen¹, Jyotishman Dasgupta¹, Jian-Zhong Wu¹, Filippo De Angeles², Roberto Car¹, Charles Dismukes^*,1, ¹ Princeton University, USA² Princeton University, USA

(P7A-10) Structural features associated with CP47, D1 and the extrinsic proteins that stabilize oxygen evolution. (Abstract 356)
Julian Eaton-Rye^*,1, Bronwyn Carlisle¹, Jackie Shand¹, Claire Martin¹, Ron Manulevu¹, ¹ Department of Biochemistry, Dunedin, New Zealand

(P7A-11) Characterization of Ser-replacement mutants in the D₁ protein Arg 64, 323 and 334 in cyanobacterium Synechocystis sp. PCC 6803. (Abstract 357)
Yashar Feyziyev^*,1, Naoki Mizusawa¹, Asako Ishii¹, Taka-aki Ono¹, ¹ Laboratory for Photo-Biology (1), Sendai, Japan

(P7A-12) The Cl^- binding site in the oxygen-evolving complex studied by FTIR spectroscopy. (Abstract 358)
Koji Hasegawa^*,1, Yukihiro Kimura¹, Taka-aki Ono¹, ¹ Laboratory for Photobiology(I), Photodynamics Research Center, RIKEN, 519-1399 Aoba, Sendai, Japan

(P7A-13) Interaction of higher S-states of the OEC with reductants: Is S₃ a radical containing state? (Abstract 359)
Nikolaos Ioannidis^*,1, Vassili Petrouleas¹, ¹ Institute of Materials Science, Athens, Greece

(P7A-14) Functional analysis of the four PsbP members encoded by multigene family in Nicotiana tabacum. (Abstract 360)
Seiko Ishihara^*,1, Yumiko Yamamoto¹, Kentaro Ifuku¹, Fumihiko Sato^{1, 2}, ¹ Grad. Sch. of Biostudies, Kyoto Univ., Kitashirakawa, Sakyo, kyoto, Japan² Fac. of Agri., Kyoto Univ., kitashirakawa, sakyo, Kyoto, Japan

(P7A-15) Detection of ¹⁸O-water sensitive and S-state dependent low-frequency vibrational modes in photosynthetic oxygen evolving complex. (Abstract 361)
Yukihiro Kimura^*,1, Asako Ishii¹, Toshihiro Yamanari², Koji Hasegawa¹, Taka-aki Ono¹, ¹ Laboratory for Photo-Biology(1), Photodynamics Research Center, RIKEN, Sendai, Japan² Faculty of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima, Japan

(P7A-16) Oxidation potentials and functional interaction with Photosystem II of manganese complexes containing bicarbonate and carboxylate ligands. (Abstract 362)
Yuri Kozlov¹, Konstantin Tikhonov¹, Jyotishman Dasgupta², Sergey Zharmukhamedov¹, Alevtina Kazakova¹, Charles Dismukes^*,2, Vyacheslav Klimov¹, ¹ Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region, RUSSIA² Princeton University, Department of Chemistry, Hoyt Laboratory, Princeton, New Jersey, USA

(P7A-17) Deuterium isotope effects on the reaction of tyrosine D with the S₂ and S₃ states of the oxygen evolving complex in Photosystem II. (Abstract 363)
Sabina Isgandarova¹, Birgit Nöring ¹, Leonid Kulik^*,1, Gernot Regner², Johannes Messinger¹, ¹ Max-Planck-Institute for Bioinorganic Chemistry, Muelheim an der Ruhr, Germany² Max-Volmer-Laboratorium for Biophysical Chemistry, Berlin, Germany

(P7A-18) Dual action of chloride ion on hydroxylamine inhibition of Photosystem II: Activation and attenuation. (Abstract 364)
Thomas Kuntzleman^*,1, Charles Yocum^{1, 2}, ¹ Department of Chemistry, Ann Arbor, MI, USA² Department of Molecular, Cellular and Developmental Biology, Ann Arbor, MI, USA

(P7A-19) Mechanism of the tyrosine Y_Z oxidation in Photosystem II studied by density functional theory. (Abstract 365)
Masami Kusunoki^*,1, Atsuhiro Adachi¹, ¹ 1-1-1, Kawasaki, Kanagawa, Japan

(P7A-20) Mechanism of the photosynthetic water oxidation reaction catalyzed by a noble Mn₄CaCl-bicarbonate cluster. (Abstract 366)
Masami Kusunoki^*,1, ¹ Department of Physics, School of Science and Technology, Meiji University, Kawasaki, Kanagawa, Japan

(P7A-21) Targeted screening for PsbO mutations in Chlamydomonas reinhardtii. (Abstract 367)
Haijun Liu^*,1, Jyoti Iyer¹, Ajay Yekkirala¹, Ron Hutchison¹, ¹ Dept of Biological Science North Dakota State University, Fargo, ND, USA

(P7A-22) Calcium release from PSII without loss of extrinsic polypeptides: The roles of temperature and potassium. (Abstract 368)
Robert McCarrick^*,1, Zachary Nagel¹, Charles Yocum¹, ¹ Chemistry Department, University of Michigan, Ann Arbor, MI, US

(P7A-23) Origin of the g=2 broad EPR signal in the Ca²⁺-depleted PS II in S₁ state. (Abstract 369)
Hiroyuki Mino^*,1, Shigeru Itoh¹, ¹ Grad. School of Sci, Nagoya University, Nagoya, JAPAN

(P7A-24) The role of the calcium ion in the S-state transitions studied by UV-absorbance difference spectroscopy. (Abstract 370)
Mohamed MIQYASS^*,1, Hans Van GORKOM¹, Marcel MAROSVOLGYI¹, ¹ Biophysic Department Huygens Laboratorium, Leiden, Netherlands

(P7A-25) Effect of illumination temperature on the miss-factor in the S-cycle. (Abstract 371)
Fatemeh Morvaridi^*,1, Yashar Feyziyev², Fikret Mamedov², Stenbjörn Styring², ¹ Department of Biochemistry, Center for Chemistry and, Lund, Sweden² Molecular Biomimetics, Uppsala University, Uppsala, Sweden

(P7A-26) The functional difference between two extrinsic 33-kDa proteins, PsbO1 and PsbO2, in Arabidopsis. (Abstract 372)
Reiko Murakami^*,1, Kentaro Ifuku¹, Atsushi Takabayashi¹, Toshiharu Shikanai⁴, Fumihiko Sato¹, Tsuyoshi Endo¹, ¹ Grad. Sch. Biostudies, Kyoto Univ. , Kyoto 606-8502, Japan⁴ Grad. Sch. Biol. Sci. , Nara Institute Sci. & Tech. , Ikoma, Nara, 630-1101, Japan

(P7A-27) Structural implications of the D1 C-terminal -carboxylate in photosynthetic oxygen evolution as studied by FTIR. (Abstract 373)
Naoki Mizusawa¹, Yukihiro Kimura¹, Asako Ishii¹, Toshihiro Yamanari², Taka-aki Ono^*,1, ¹ Laboratory for Photo-Biology (I), Photodynamics Research Center, RIKEN, 519-1399 Aoba, Sendai, Japan² Faculty of Integrated Arts and Sciences, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Japan

(P7A-28) Studies on the mechanism of oxidative water cleavage in cyanobacteria and plants. (Abstract 374)
Gernot Renger^*,1, ¹ Max Volmer Laboratorium für Biophysikalische Chemie, Berlin, Berlin, Germany

(P7A-29) Modelling the Mn₄Ca cluster of the water-oxidizing complex of Photosystem II. (Abstract 375)
Kenneth Sauer^{*,1, 2}, Junko Yano^{1, 2}, Vittal Yachandra¹, ¹ Lawrence Berkeley National Laboratory, Berkeley, CA, USA² Department of Chemistry, University of California, Berkeley, CA, USA

(P7A-30) Characterization of the "Split" EPR-signal from Tyr-Z-S1 in PSII with Tyr-D reduced. (Abstract 376)
Kajsa Sigfridsson^*,1, Yashar Feyziyev^*,2, Stenbjörn Styring¹, ¹ Molecular Biomimetics, Uppsala, Sweden² Laboratory for Photobiology, Photodynamic Research Center, Sendai, Japan

(P7A-31) Photosystem II carbonic anhydrases and the oxidizing-side bicarbonate effect. (Abstract 377)
Yih-Kuang Lu, Alan Stemler^*,,

(P7A-32) The role of the chloride ion in the oxygen evolving complex. (Abstract 378)
Hans van Gorkom^*,1, Charles Yocum², ¹ Department of Biophysics, Huygens Laboratory, Leiden, Netherlands² Departments of Biology and of Chemistry, Ann Arbor, MI, USA

(P7A-33) The influence of the D1-H332 residue on the energetics of the S₂ state. (Abstract 379)
Imre Vass^*,1, Yagut Allakhverdieva¹, Krisztián Cser¹, Zsuzsanna Deák¹, Bruce Diner², Peter Nixon³, ¹ Institute of Plant Biology, Biological Research Center, Szeged, Hungary² CR&D, Experimental Station, E.I. du Pont de Nemours and Co., Wilmington, DE, USA³ Department of Biological Sciences, Imperial College London, Biochemistry Building, South Kensington campus, London, UK

(P7A-34) Release of calcium from PSII by monovalent metal ions. (Abstract 380)
Charles Yocum^*,1, Zachary Nagel¹, ¹ Departments of MCD Biology and of Chemistry, Ann Arbor, MI, USA

(P7A-35) Tyrosine z redox chemistry in active Photosystem II at cryogenic temperature. (Abstract 381)
Chunxi Zhang^*,1, Alfred Rutherford¹, ¹ Service de Bioénergétique, CNRS URA 2096, Département de Biologie Joliot-Curie, Paris, France