Sökning: "S2 state"

Visar resultat 11 - 15 av 20 avhandlingar innehållade orden S2 state.

  1. 11. Trapping Tyrosine Z : Exploring the Relay between Photochemistry and Water Oxidation in Photosystem II

    Författare :Johannes Sjöholm; Stenbjörn Styring; Fikret Mamedov; A. William Rutherford; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Photosystem II; Tyrosine Z; EPR; proton-coupled electron transfer; hydrogen bond; pH;

    Sammanfattning : Photosystem II is unique! It remains the only enzyme that can oxidize water using light as energy input. Water oxidation in photosystem II is catalyzed by the CaMn4 cluster. The electrons extracted from the CaMn4 cluster are transferred to P680+ via the tyrosine residue D1-Tyr161 (YZ). LÄS MER

  2. 12. Oxidation and reduction reactions of the water-oxidizing complex in photosystem II

    Författare :Long Vo Pham; Johannes Messinger; Imre Vass; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Photosystem II PSII ; oxidation; reduction; flash induced oxygen evolution pattern FIOP ; water; oxygen; global fitting program GFP ; thylakoids; fysikalisk kemi; Physical Chemistry;

    Sammanfattning : The oxygen that we breathe and food that we eat are products of the natural photosynthesis. Molecular oxygen is crucial for life on Earth owing to its role in the glycolysis and citric acid pathways that yield in aerobic organisms the energy-rich ATP molecules. LÄS MER

  3. 13. Time-resolved Structural and Mechanistic Studies of Water Oxidation in Photosystem II : water here, water there, water everywhere

    Författare :Casper de Lichtenberg; Johannes Messinger; Wolfgang P. Schröder; Holger Dau; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Oxygenic Photosynthesis; Photosystem II; TR-MIMS; isotope exchange; EPR; EDNMR; water splitting; water oxidation;

    Sammanfattning : Oxygenic photosynthesis is undisputedly one of the most important chemical processes for human life on earth as it not only fills the atmosphere with the oxygen that we need to breathe, but also sustains the accumulation of biomass, which is not only used as nourishment but is also present in almost every aspect of our lives as building material, textiles in clothes and furniture, or even as living decorations to name a few.The photosynthetic water-splitting mechanism is catalyzed by a water:plastoquinone oxido-reductase by the name of photosystem II (PSII), which is embedded in the thylakoid membranes of plants, algae and cyanobacteria. LÄS MER

  4. 14. Reaction mechanism of metalloenzymes studied by theoretical methods

    Författare :Geng Dong; Beräkningskemi; []
    Nyckelord :Metalloenzymes; Reaction mechanism; QM MM; DFT; DMRG; CAS-srDFT; Big-QM; QTCP;

    Sammanfattning : Metalloenzymes catalyse a wide variety of reactions in nature. In the thesis, I have studied the reaction mechanism of three metalloenzymes, viz. LÄS MER

  5. 15. Substrate water binding to the oxygen-evolving complex in photosystem II

    Författare :Håkan Nilsson; Johannes Messinger; Wolfgang Schröder; Robert L. Burnap; Umeå universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Photosynthesis; Photosystem II; water oxidation; oxygen evolution; substrate water exchange; membrane-inlet mass spectrometry;

    Sammanfattning : Oxygenic photosynthesis in plants, algae and cyanobacteria converts sunlight into chemical energy. In this process electrons are transferred from water molecules to CO2 leading to the assembly of carbohydrates, the building blocks of life. LÄS MER