Springer Theses Recognizing Outstanding Ph.D. Research Shin Nakamura Molecular Mechanisms of Proton-coupled Electron Transfer and Water Oxidation in Photosystem II Springer Theses Recognizing Outstanding Ph.D. Research Aims and Scope The series “Springer Theses” brings together a selection of the very best Ph.D. theses from around the world and across the physical sciences. Nominated and endorsed by two recognized specialists, each published volume has been selected foritsscientificexcellenceandthehighimpactofitscontentsforthepertinentfield of research. For greater accessibility to non-specialists, the published versions includeanextendedintroduction,aswellasaforewordbythestudent’ssupervisor explainingthespecialrelevanceoftheworkforthefield.Asawhole,theserieswill provide a valuable resource both for newcomers to the research fields described, and for other scientists seeking detailed background information on special questions. 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More information about this series at http://www.springer.com/series/8790 Shin Nakamura Molecular Mechanisms of Proton-coupled Electron Transfer and Water Oxidation in Photosystem II Doctoral Thesis accepted by Nagoya University, Nagoya, Japan 123 Author Supervisor Dr. ShinNakamura Prof. TakumiNoguchi Department ofBiochemical Sciences Division of Material Science(Physics) “A.Rossi Fanelli” Graduate Schoolof Science University of Rome“Sapienza” Nagoya University Rome, Italy Nagoya,Japan ISSN 2190-5053 ISSN 2190-5061 (electronic) SpringerTheses ISBN978-981-15-1583-5 ISBN978-981-15-1584-2 (eBook) https://doi.org/10.1007/978-981-15-1584-2 ©SpringerNatureSingaporePteLtd.2020 Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpart of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission orinformationstorageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilar methodologynowknownorhereafterdeveloped. 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The registered company address is: 152 Beach Road, #21-01/04 Gateway East, Singapore 189721, Singapore ’ Supervisor s Foreword Photosynthetic water oxidation, which is performed in photosystem II (PSII) in plants and cyanobacteria, is one of the most essential enzymatic reactions in bio- logicalsystems.Utilizinglightenergy,wateroxidationprovideselectronsnecessary for reduction in CO to synthesize sugars and produces molecular oxygen to form 2 the oxygenic atmosphere, and thus, it supports the sustenance of the environment and life on the Earth. We now know the basic structure of the catalytic center of wateroxidation,theso-calledMncluster,thankstotherecenthigh-resolutionX-ray crystallographic studies of PSII. However, the molecular mechanism of water oxidation, in which protons play the main role, is still the greatest mystery in photosynthesis research. The key to answer the question is to understand how protonsarecoupledwithelectrontransfer,whichcontrolsthewholemechanismof water oxidation. Inthisthesis,ShinNakamuratackledtheelusiveproblemofthewateroxidation mechanism using both experimental and theoretical approaches such as Fourier transform infrared measurements and quantum mechanics/molecular mechanics simulations. Using these methodologies, he first addressed the mechanism of asymmetricelectrontransferontheelectron-donorsideofPSII,whichisrelevantto the high quantum yield of water oxidation. He also analyzed the structures and vibrationsofwaternetworksneartheMnclusterandproposedanewmechanismof protontransferduringwateroxidation.Furthermore,heclarifiedtherolesofamino acidresiduesinteractingwiththeMnclusterwithrespecttothecontroloftheredox potential and the activation of water molecules. I believe that his work not only providesasignificantcontributiontoresearchofthewateroxidationmechanismbut alsooffersanessentialbasisforthedevelopmentofefficientphotocatalystsofwater oxidation, which is the bottleneck in artificial photosynthesis. Nagoya, Japan Prof. Takumi Noguchi December 2019 v Parts of this thesis have been published in the following journal articles: (1) S. Nakamura, R. Nagao, R. Takahashi, and T. Noguchi (2014) Fourier trans- form infrared detection of a polarizable proton trapped between photooxidized tyrosine Y and a coupled histidine in photosystem II: relevance to the proton Z transfer mechanism of water oxidation. Biochemistry 53, 3131–3144. (2) S. Nakamura and T. Noguchi (2015) Infrared detection of a proton released from tyrosine Y to the bulk upon its photo-oxidation in photosystem II, D Biochemistry 54, 5045–5053 (3) S. Nakamura, K. Ota, Y. Shibuya, and T. Noguchi (2016) Role of a water network around the Mn4CaO5 cluster in photosynthetic water oxidation: A Fourier transform infrared spectroscopy and quantum mechanics/molecular mechanics calculation study, Biochemistry 55, 597–607 (4) S.Nakamura,andT.Noguchi(2016)Quantummechanics/molecularmechanics simulation of the ligand vibrations of the water-oxidizing Mn CaO cluster in 4 5 photosystem II, Proc.Natl. Acad. Sci. U.S.A. 113, 12727–12732 (5) S.Nakamura,andT.Noguchi(2017)Infrareddeterminationoftheprotonation state of a key histidine residue in the photosynthetic water oxidizing center, J. Am. Chem. Soc. 139, 9364–9375. vii Acknowledgements Iwouldliketoexpressmygratitudetoallofthosewhogavemetheopportunityto complete this thesis. I am especially indebted to my supervisor, Prof. Takumi Noguchi, for providing me his knowledge, guidance, and technical supports. I learned the importance of objectivity and perseverance in science through the research activities with him. IdeeplyappreciateDr.RyoNagaoforsignificanttechnicaladvicesandsupports for sample preparations. I learned most of the biochemical techniques used in the presentworkfromhim.IalsoappreciateDr.RyoutaTakahashiandMr.KaiOtafor their technical supports in FTIR measurements and Mr. Ryota Ashizawa for his advice on computational techniques. Finally, I greatly thank Prof. Hiroyuki Mino, Prof.YukiKato,andallmembersinthelaboratoryforhelpfuldiscussionandkind supports. This research was supported by Japan Society for the Promotion of Science (JSPS) Fellows Grant-in-Aid 15J10320. QM/MM calculations were performed at the Research Center for Computational Science, Okazaki, Japan, and Information Technology Center, Nagoya University. ix Contents 1 General Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Photosystem II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Fourier Transform Infrared Spectroscopy (FTIR) . . . . . . . . . . . . . 4 1.3 Quantum Chemical Calculation . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.4 Purpose of This Study. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2 Hydrogen Bond Structure of Redox Active Tyrosines in Photosystem II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2.2 Materials and Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2.3 Results. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 2.4 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 3 Proton Release Reaction of Tyrosine D in Photosystem II . . . . . . . . 37 3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 3.2 Materials and Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 3.3 Results. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 3.4 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 4 Vibrational Analysis of Water Network Around the Mn Cluster . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 4.2 Materials and Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 4.3 Results. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 4.4 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 xi xii Contents 5 Vibrational Analysis of Carboxylate Ligands in the Water Oxidizing Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 5.2 Materials and Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 5.3 Results. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 5.4 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 6 Protonation Structure of a Key Histidine in the Water Oxidizing Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 6.2 Materials and Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 6.3 Results. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 6.4 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 7 General Conclusion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123 Curriculum Vitae .. .... .... ..... .... .... .... .... .... ..... .... 125