Physical chemistry of water oxidation and electron transfer in photosystem II of oxygenic photosynthesis

2017 Fiscal Year Final Research Report

• Project/Area Number: 16K17854
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Physical chemistry
• Research Institution: Nagoya University
• Principal Investigator: Kato Yuki 名古屋大学, 理学研究科, 講師 (10376634)
• Project Period (FY): 2016-04-01 – 2018-03-31
• Keywords: 光合成 / 水分解 / 酸素発生 / 電子伝達 / 光化学系 / 酸化還元電位 / マンガンクラスター / 分光電気化学

Outline of Final Research Achievements

The redox potential of the primary quinone QA, Em(QA), in PSII has been estimated to be -100 mV in intact samples and shown to be shifted by ca. +150 mV upon Mn depletion. These values have been obtained by a fluorescence method, which indirectly monitors the redox state of QA. In this work, we measured the Em(QA) in intact and Mn-depleted PSII preparations using FTIR spectroelectrochemistry, which can directly detect the redox reaction of QA. The Em(QA) in intact PSII was determined to be -100 mV in agreement with that by the fluorescence method. However, the Em(QA) value was little affected by Mn depletion. It is thus suggested that the large Em(QA) upshift by Mn depletion found in previous works can be an artifact due to the fluorescence method.

Free Research Field

生物物理化学