記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Frontiers Media SA  

Light energy is converted to chemical energy by two photosystems (PSI and PSII) in complex with their light-harvesting complex proteins (LHCI and LHCII) in photosynthesis. Rhodomonas is a member of cryptophyte alga whose LHCs contain unique chlorophyll a/c proteins (ACPs) and phycobiliproteins. We purified PSI-ACPI and PSII-ACPII supercomplexes from a cryptophyte Rhodomonas sp. NIES-2332 and analyzed their structures at high resolutions of 2.08 Å and 2.17 Å, respectively, using cryo-electron microscopy. These structures are largely similar to those reported previously from two other species of cryptophytes, but exhibited some differences in both the pigment locations and subunit structures. A part of the antenna subunits of both photosystems is shifted compared with the previously reported structures from other species of cryptophytes, suggesting some differences in the energy transfer rates from the antenna to the PSI and PSII cores. Newly identified lipids are found to occupy the interfaces between the antennae and cores, which may be important for assembly and stabilization of the supercomplexes. Water molecules surrounding three iron-sulfur clusters of the PSI core are found in our high-resolution structure, some of which are conserved from cyanobacteria to higher plants but some are different. In addition, our structure of PSII-ACPII lacks the subunits of oxygen-evolving complex as well as the Mn ₄ CaO ₅ cluster, suggesting that the cells are in the S-growth phase, yet the PSI-ACPI structure showed the binding of PsaQ, suggesting that it is in an L-phase. These results suggest that the S-phase and L-phase can co-exist in the cryptophytic cells. The high-resolution structures of both PSI-ACPIs and PSII-ACPIIs solved in this study provide a more solid structural basis for elucidating the energy transfer and quenching mechanisms in this group of the organisms.

DOI： 10.3389/fpls.2025.1716939

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Haptophytes are unicellular algae that produce 30 to 50% of biomass in oceans. Among haptophytes, a subset named coccolithophores is characterized by calcified scales. Despite the importance of coccolithophores in global carbon fixation and CaCO3 production, their energy conversion system is still poorly known. Here we report a cryo-electron microscopic structure of photosystem II (PSII)-fucoxanthin chlorophyll c-binding protein (FCPII) supercomplex from Chyrostila roscoffensis, a representative of coccolithophores. This complex has two sets of six dimeric and monomeric FCPIIs, with distinct orientations. Interfaces of both FCPII/FCPII and FCPII/core differ from previously reported. We also determine the sequence of Psb36, a subunit previously found in diatoms and red algae. The principal excitation energy transfer (EET) pathways involve mainly 5 FCPIIs, where one FCPII monomer mediates EET to CP47. Our findings provide a solid structural basis for EET and energy dissipation pathways occurring in coccolithophores.

DOI： 10.1038/s41467-025-59512-9

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.bbabio.2025.149543

PubMed

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：American Society for Microbiology  

Cumene dioxygenase (CumDO) is an initial enzyme in the cumene degradation pathway of Pseudomonas fluorescens IP01 and is a Rieske non-heme iron oxygenase (RO) that comprises two electron transfer components (reductase [CumDO-R] and Rieske-type ferredoxin [CumDO-F]) and one catalytic component (α3β3-type oxygenase [CumDO-O]). Catalysis is triggered by electrons that are transferred from NAD(P)H to CumDO-O by CumDO-R and CumDO-F. To investigate the binding mode between CumDO-F and CumDO-O and to identify the key CumDO-O amino acid residues for binding, we simulated docking between the CumDO-O crystal structure and predicted model of CumDO-F and identified two potential binding sites: one is at the side-wise site and the other is at the top-wise site in mushroom-like CumDO-O. Then, we performed alanine mutagenesis of 16 surface amino acid residues at two potential binding sites. The results of reduction efficiency analyses using the purified components indicated that CumDO-F bound at the side-wise site of CumDO-O, and K117 of the α-subunit and R65 of the β-subunit were critical for the interaction. Moreover, these two positively charged residues are well conserved in α3β3-type oxygenase components of ROs whose electron donors are Rieske-type ferredoxins. Given that these residues were not conserved if the electron donors were different types of ferredoxins or reductases, the side-wise site of the mushroom-like structure is thought to be the common binding site between Rieske-type ferredoxin and α3β3-type oxygenase components in ROs.

DOI： 10.1128/aem.00835-22

PubMed

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担当区分：筆頭著者,　最終著者,　責任著者   記述言語：英語   掲載種別：学位論文（博士）  

DOI： 10.15083/0002004915

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J-GLOBAL

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開催年月日： 2025年9月24日 - 2025年9月26日

記述言語：英語   会議種別：ポスター発表  

開催地：奈良  

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開催年月日： 2025年9月8日 - 2025年9月12日

記述言語：英語   会議種別：口頭発表（一般）  

開催地：青島  

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開催年月日： 2025年7月26日 - 2025年7月30日

記述言語：英語   会議種別：ポスター発表  

開催地：Milwaukee  

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開催年月日： 2025年3月14日 - 2025年3月16日

記述言語：英語   会議種別：口頭発表（一般）  

開催地：金沢  

添付ファイル： JSPP2025_slides蔡弼丞.pdf

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開催年月日： 2025年3月4日 - 2025年3月8日

記述言語：英語   会議種別：ポスター発表  

開催地：札幌  

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作品分類：データベース   発表場所：EMPIAR - Electron Microscopy Public Image Archive  

DOI： 10.6019/EMPIAR-12501

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作品分類：データベース   発表場所：RCSB Protein Data Bank  

DOI： 10.2210/pdb9KQB/pdb

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作品分類：データベース   発表場所：RCSB Protein Data Bank  

DOI： 10.2210/pdb9KQQ/pdb

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作品分類：データベース   発表場所：RCSB Protein Data Bank  

DOI： 10.2210/pdb9KQP

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対象： 大学生,　大学院生,　研究者,　社会人・一般

種別：講演会

添付ファイル： (4_3)2025第三屆JTBA年會-宣傳海報(草稿)_20251112.png

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対象： 大学院生,　研究者,　社会人・一般

種別：セミナー・ワークショップ

添付ファイル： btba-jtba-e4baa4e6b581e69c83-jtba.jpg

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対象： 大学生,　大学院生,　研究者,　社会人・一般

種別：講演会

添付ファイル： (更新版) 年會海報.png

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対象： 大学生,　大学院生,　研究者,　社会人・一般

種別：講演会

添付ファイル： 第二波宣傳_海報 (講者更改+協贊單位).png

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種別：学会・研究会等 

添付ファイル： WS.png

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