Article
Chemistry, Multidisciplinary
Yu Guo, Johannes Messinger, Lars Kloo, Licheng Sun
Summary: O2 formation in photosystem II (PSII) is still not well understood, but the prevailing theoretical model involves a Mn(IV)-oxyl unit in an open-cubane Mn4CaO6 cluster. However, it has been proposed that the S3 state of higher plants lacks an extra ligand, and instead features a penta-coordinate dangler Mn(V)=oxo covalently linked to a closed-cubane Mn3CaO4 cluster. In this study, the researchers explored various possible pathways and found that the nucleophilic oxo-oxo coupling (NOOC) between Mn(V)=oxo and mu 3-oxo is the only feasible mechanism. They described an energetically feasible process starting from the S4 state, involving the formation of peroxide and superoxide, followed by O2 release and a second water insertion.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Jaruwan Amtawong, Bastian Bjerkem Skjelstad, Rex C. Handford, Benjamin A. Suslick, David Balcells, T. Don Tilley
Summary: High-valent multimetallic-oxo/oxyl species have been studied as intermediates in oxidative catalysis involving PCET reactions. The mechanism of C-H oxidation by RuCo3O4 cubane complexes was investigated, revealing a barrierless radical combination step and insights into cooperative effects of multimetallic centers in tuning PCET reactivity. Tuning the electronic properties of the cubane modulates C-H activations and enables construction of structure-activity relationships.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Yu-Cheng Shao, Cheng-Tai Kuo, Xuefei Feng, Yi-De Chuang, Tae Jun Seok, Ji Hyeon Choi, Tae Joo Park, Deok-Yong Cho
Summary: The study reveals that the Ti3+ state in the Al2O3/TiO2 2D electron system serves as an n-type dopant at the deep interface, with electronic structure distinct from the Ti4+ host lattice. Experimental results demonstrate significant electron-phonon coupling effects in TiO2 samples, particularly in thinner samples.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Biochemistry & Molecular Biology
Boleslaw Karwowski
Summary: Every 24 h, a large number of DNA damage incidents occur in the human body, which are similar to those induced by radiotherapy or chemotherapy. The presence of clustered DNA damage is higher in anticancer treatment compared to normal tissues. The most common lesion is (OXO)G. This study investigates the impact of (OXO)G, as isolated or clustered DNA lesions, on charge transfer and provides insights into the repair mechanism and ionization potential.
Article
Chemistry, Multidisciplinary
Sisi Xin, Yu Tang, Baohua Jia, Zhengfu Zhang, Chengping Li, Rui Bao, Caiju Li, Jianhong Yi, Jinsong Wang, Tianyi Ma
Summary: In this study, a Fe-Co(OH)(2)/Fe2O3 heterostructure was proposed, which combines the AEM and LOM mechanisms to optimize the distribution of adsorbed and lattice oxygen, thus improving the activity and stability of OER.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Physical
Jialu Chen, Ruiqin Zhang
Summary: This study investigates the influence of phosphine ligands on cross-coupling reactions and proposes a descriptor %V-bur (min) - 3 center dot HOMO-LUMO gap (eV) to reveal the ligands' effects. The yields of the reactions are plotted against the descriptor on volcano plots to optimize the reaction yields.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Physical
Sandra M. Lang, Nina Zimmermann, Thorsten M. Bernhardt, Robert N. Barnett, Bokwon Yoon, Uzi Landman
Summary: Gas-phase ion-trap reactivity experiments and density functional simulations show that water oxidation to H2O2 mediated by (calcium) manganese oxide clusters proceeds via formation of a terminal oxyl radical followed by oxyl/hydroxy O-O coupling. The reaction is predicted to be energetically feasible for certain clusters, but does not proceed for tetramanganese oxides due to their high fluxionality. Calcium doping stabilizes the oxyl radical configuration and enables the cluster-mediated water oxidation reaction and H2O2 formation through favorable coupling between potential energy surfaces with different spin states.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Materials Science, Multidisciplinary
G. Nag Bhargavi, Tanmaya Badapanda, Ayush Khare, M. Shahid Anwar, Nameeta Brahme
Summary: This study investigates the impact of substituting Europium in BaZr0.05Ti0.95O3 ceramic on its electrical properties. It was found that the electrical conductivity decreases with increasing Europium content, and the crystal structure shifts from orthorhombic to tetragonal with Eu doping.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2021)
Article
Multidisciplinary Sciences
Haigen Fu, Jingzhe Cao, Tianzhang Qiao, Yuyin Qi, Simon J. Charnock, Samuel Garfinkle, Todd K. Hyster
Summary: This study reports a highly chemoselective and enantioselective Csp(3)-Csp(3) XEC reaction catalyzed by flavin-dependent 'ene'-reductases (EREDs). The photoexcitation of the enzyme-templated charge-transfer complex enables the chemoselective reduction of alkyl halides and high enantioselectivity.
Article
Chemistry, Applied
Andrey S. Chikunov, Svetlana A. Yashnik, Oxana P. Taran, Anna Y. Kurenkova, Valentin N. Parmon
Summary: Water oxidation is a key step in the water splitting process, and a highly efficient and stable Cu-containing catalyst supported on zeolite has been developed for this purpose. The analysis of electron states of copper in the catalyst revealed that [Cu2(OH)2]2+ complexes in the zeolite channels demonstrated the highest catalytic efficiency. Additionally, the presence of CuOx-like complexes stabilized in the channels significantly increased the oxygen yield in a photocatalytic system.
Article
Chemistry, Multidisciplinary
Juan A. Valdez-Moreira, Daniel M. Beagan, Hao Yang, Joshua Telser, Brian M. Hoffman, Maren Pink, Veronica Carta, Jeremy M. Smith
Summary: The study characterized a thermally stable iron(III) oxo complex and analyzed its structure, spectroscopic, and computational properties. The complex has an unusually short iron-oxygen bond length and is able to perform hydrocarbon oxidations.
ACS CENTRAL SCIENCE
(2021)
Article
Optics
Ruiyun Chen, Bo Xia, WenJin Zhou, Wenling Guan, Guofeng Zhang, Chengbing Qin, Jianyong Hu, Liantuan Xiao, Suotang Jia
Summary: The study found that using polymer encapsulation can improve the photostability of perovskite materials, but may lead to a loss in photoluminescence properties. The effects of polymer and solvent on individual perovskite crystals during the encapsulation process have important implications for the stability and performance of the final devices.
Article
Engineering, Environmental
Xinxin Long, Chuanping Feng, Dahu Ding, Nan Chen, Shengjiong Yang, Huanyu Chen, Xinming Wang, Rongzhi Chen
Summary: In this study, a series of MOF-derived CoFe2O4 nanomaterials with tuned oxygen vacancies were prepared for peroxymonosulfate activation. The abundant surface oxygen vacancies and functional groups on CoFe2O4 were identified as active sites to boost catalytic activity. Different annealing temperatures influenced the stability, structural, and catalytic properties of the materials.
JOURNAL OF HAZARDOUS MATERIALS
(2021)
Article
Chemistry, Inorganic & Nuclear
M. Qadri E. Mubarak, Hafiz Saqib Ali, Jimei Zhou, Chaoqun Li, Jianliang Xiao, Sam P. de Visser
Summary: In this study, a biomimetic model complex with a 1,1'-bis((3,5-dimethylpyridin-2-yl)methyl)-2,2'-bipiperidine ligand system bound to a manganese(IV)-oxo(hydroxo) species was investigated. The formation of this complex from manganese(II)-hydroxo and H2O2, as well as its reaction with (S)-1-phenylisochromane through dehydrogenative alpha-oxygenation, were studied using density functional theory methods. The results revealed that the manganese(IV)-oxo(hydroxo) species is an active oxidant and has lower barriers for hydrogen atom abstraction than the hydroxo group. Surprisingly, the rate-determining step was found to be the OH rebound rather than the hydrogen atom abstraction, suggesting limited kinetic isotope effect for hydrogen atom replacement with deuterium.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Jacob L. Shelton, Kathryn E. Knowles
Summary: Polaron formation following optical absorption is a crucial process that affects the photophysical properties of transition metal oxide semiconductors. This study demonstrates the feasibility of directly populating band edge polaronic states in hematite and reveals their temperature evolution through first-principles electron-phonon computations.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Biochemistry & Molecular Biology
Melinda Magyar, Gabor Sipka, Wenhui Han, Xingyue Li, Guangye Han, Jian-Ren Shen, Petar H. H. Lambrev, Gyozo Garab
Summary: By measuring the chlorophyll-a fluorescence transients produced by single-turnover saturating flashes, researchers identified the rate-limiting steps in the transition from dark to light of Photosystem II. They found that in samples treated with diuron, the first flash fully reduced the Q(A) quinone acceptor molecule but only generated an F-1 fluorescence transient.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Chemistry, Multidisciplinary
Tetsuo Katayama, Tae-Kyu Choi, Dmitry Khakhulin, Asmus Dohn, Christopher Milne, Gyoergy Vanko, Zoltan Nemeth, Frederico Lima, Jakub Szlachetko, Tokushi Sato, Shunsuke Nozawa, Shin-ichi Adachi, Makina Yabashi, Thomas Penfold, Wojciech Gawelda, Gianluca Levi
Summary: By simultaneously measuring femtosecond X-ray emission and scattering, the intramolecular and solvation structural dynamics following photoexcitation of a solvated copper photosensitizer were tracked. The results reveal that photoinduced solute and solvent motions can be intimately intertwined, explaining the influence of the solvent on the initial steps of light harvesting. This work is a step forward in understanding the microscopic mechanisms of the bidirectional influence between transient solvent reorganization and photoinduced solute structural dynamics.
Article
Instruments & Instrumentation
Artoni Kevin R. Ang, Yasufumi Umena, Ayana Sato-Tomita, Naoya Shibayama, Naohisa Happo, Riho Marumi, Yuta Yamamoto, Koji Kimura, Naomi Kawamura, Yu Takano, Tomohiro Matsushita, Yuji C. Sasaki, Jian-Ren Shen, Kouichi Hayashi
Summary: X-ray fluorescence holography (XFH) is a powerful atomic resolution technique that directly images the local atomic structure of a target element in a material. The development of serial X-ray fluorescence holography allows for direct recording of hologram patterns before radiation damage occurs. This technique paves the way for future experiments on protein crystals to study the local atomic structures of their metal clusters.
JOURNAL OF SYNCHROTRON RADIATION
(2023)
Article
Chemistry, Multidisciplinary
Takahiro Iwai, Sadao Honda, Shimpei Watanabe, Ritsuko Matsushita, Toshio Nakanishi, Masahisa Takatsu, Taro Moriwaki, Makina Yabashi, Tetsuya Ishikawa, Yasuo Seto
Summary: Quantitative evaluation of drug mixing condition for forensic discrimination of drug powders was conducted using micro Fourier transform infrared (FT-IR) spectroscopy. Different mixing modes were tested by mixing, homogenizing, dissolving, and drying processes. The spatial localization and distribution of the drugs were analyzed and evaluated using synchrotron radiation (SR) or globar light with different instruments. The differentiation among the mixing modes was assessed using mixing parameters including the relative content ratio (RCR) and extreme value frequency (%EV) as mixing indices. The discrimination capacity of the SR instrument was found to be superior to that of the globar light instrument.
Article
Multidisciplinary Sciences
Dan-Hong Li, Wenda Wang, Cuicui Zhou, Yan Zhang, Songhao Zhao, Yi-Ming Zhou, Rong-Yao Gao, Hai-Dan Yao, Li-Min Fu, Peng Wang, Jian-Ren Shen, Tingyun Kuang, Jian-Ping Zhang
Summary: The light-harvesting complex II (LHCII) of Bryopsis corticulans differs in chlorophyll and carotenoid compositions from that of spinach. Using time-resolved absorption spectroscopy, we investigated the ultrafast excitation dynamics of B-LHCII. Our results showed rapid photogeneration of Chl-Chl charge transfer (CT) species and revealed the transfer of singlet excitation between different chlorophyll and carotenoid molecules. The induction of Chl-Chl CT species by red-light excitation is a common occurrence for LHCIIs in light-harvesting form, as observed in S-LHCII.
Article
Multidisciplinary Sciences
Ryo Nagao, Koji Kato, Tasuku Hamaguchi, Yoshifumi Ueno, Naoki Tsuboshita, Shota Shimizu, Miyu Furutani, Shigeki Ehira, Yoshiki Nakajima, Keisuke Kawakami, Takehiro Suzuki, Naoshi Dohmae, Seiji Akimoto, Koji Yonekura, Jian-Ren Shen
Summary: By using cryo-EM, the authors determined the structure of a PSI monomer associated with six IsiA proteins in Anabaena, providing insights into the diversity and functions of IsiAs. IsiAs are expressed in cyanobacteria under iron-deficient conditions, and the binding properties and functional roles of IsiAs in PSI were still unknown in Anabaena. The cryo-EM structure of a PSI-IsiA supercomplex isolated from iron-deficient Anabaena revealed the association of six IsiA subunits with a PSI core monomer, and the absence of a PsaL subunit due to the occupation of its position by the C-terminal domain of IsiA2.
NATURE COMMUNICATIONS
(2023)
Article
Biochemical Research Methods
Kunio Nakata, Tatsuki Kashiwagi, Naoki Kunishima, Hisashi Naitow, Yoshinori Matsuura, Hiroshi Miyano, Toshimi Mizukoshi, Kensuke Tono, Makina Yabashi, Eriko Nango, So Iwata
Summary: Phosphoketolase and transketolase are important enzymes in the primary metabolism of bifidobacteria. They catalyze the cleavage of xylulose 5-phosphate or fructose 6-phosphate in the first reaction step and have different substrate specificity in the second reaction step. The structures of these enzymes have been determined using crystallography and X-ray free-electron laser.
ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Yoshiaki Kumagai, Weiqing Xu, Kazuki Asa, Toshiyuki Hiraki Nishiyama, Koji Motomura, Shin-ichi Wada, Denys Iablonskyi, Subhendu Mondal, Tetsuya Tachibana, Yuta Ito, Tsukasa Sakai, Kenji Matsunami, Takayuki Umemoto, Christophe Nicolas, Catalin Miron, Tadashi Togashi, Kanade Ogawa, Shigeki Owada, Kensuke Tono, Makina Yabashi, Hironobu Fukuzawa, Kiyonobu Nagaya, Kiyoshi Ueda
Summary: We studied the behavior of nanoplasma generated by the interaction of a hard X-ray pulse with xenon clusters using electron and ion spectroscopy. Through the dependence on XFEL intensity and cluster size, we gained a deep understanding of the formation and disintegration processes of XFEL-ignited nanoplasma. We also tracked the time evolution of plasma electrons within the nanoplasma using a near-infrared probe pulse and observed an unexpected time delay dependence of ion yield enhancement due to NIR pulse heating, indicating an inhomogeneous spatial distribution of plasma electrons.
APPLIED SCIENCES-BASEL
(2023)
Article
Biochemistry & Molecular Biology
Seiya Tajima, Yoon Seok Kim, Masahiro Fukuda, Youngju Jo, Peter Y. Wang, Joseph M. Paggi, Masatoshi Inoue, Eamon F. X. Byrne, Koichiro E. Kishi, Seiwa Nakamura, Charu Ramakrishnan, Shunki Takaramoto, Takashi Nagata, Masae Konno, Masahiro Sugiura, Kota Katayama, Toshiki E. Matsui, Keitaro Yamashita, Suhyang Kim, Hisako Ikeda, Jaeah Kim, Hideki Kandori, Ron O. Dror, Keiichi Inoue, Karl Deisseroth, Hideaki E. Kato
Summary: KCR channelrhodopsins exhibit a distinctive mechanism for K+ selectivity, involving the formation of an asymmetric selectivity gate and a distinct dehydration pathway. The discovery of this mechanism provides a framework for studying ion-channel selectivity and advancing optogenetic applications.
Article
Chemistry, Multidisciplinary
Jaemyung Kim, Yujiro Hayashi, Makina Yabashi
Summary: The microstructure of a material is crucial for determining its properties and potential malfunctions. This study presents a novel method, called inclined scanning 3D X-ray diffraction (iS3DXRD) microscopy, that enhances the spatial resolution of 3D grain orientation maps in polycrystalline materials. The method combines an inclined geometry with sub-voxel analysis and has been successfully validated for alpha-Fe wire, producing a high-resolution 3D grain orientation map.
JOURNAL OF APPLIED CRYSTALLOGRAPHY
(2023)
Article
Instruments & Instrumentation
Jaemyung Kim, Yujiro Hayashi, Makina Yabashi
Summary: The spatial resolution of scanning-based two-dimensional microscopy is limited by the size of the probe, but this assumption may change in three-dimensional microscopy where probe trajectories overlap. This study investigates the spatial resolution achieved in scanning three-dimensional X-ray diffraction microscopy and finds that dividing pixels into smaller sections for sub-pixel analysis leads to a significant improvement in spatial resolution.
JOURNAL OF SYNCHROTRON RADIATION
(2023)
Article
Instruments & Instrumentation
Eito Iwai, Ichiro Inoue, Hirokazu Maesaka, Takahiro Inagaki, Makina Yabashi, Toru Hara, Hitoshi Tanaka
Summary: A machine-learning-based beam optimizer was implemented to maximize spectral brightness and narrow the spectral width of SACLA's XFEL pulses. A new high-resolution spectrometer was used to measure and evaluate the spectra, resulting in improved spectral brightness and narrower width.
JOURNAL OF SYNCHROTRON RADIATION
(2023)
Article
Chemistry, Multidisciplinary
Erika Tsutsumi, Satomi Niwa, Ryota Takeda, Natsuki Sakamoto, Kei Okatsu, Shuya Fukai, Hideo Ago, Satoshi Nagao, Hiroshi Sekiguchi, Kazuki Takeda
Summary: In this study, the authors analyzed the structure of a Zn-containing form of a Rieske protein and found that zinc ions might play a role in the insertion of [2Fe-2S] clusters. They also revealed the conformational changes of the protein before metal cluster insertion.
COMMUNICATIONS CHEMISTRY
(2023)
Article
Biochemistry & Molecular Biology
Junko Tanaka, Satoshi Abe, Tohru Hayakawa, Mariko Kojima, Keitaro Yamashita, Kunio Hirata, Takafumi Ueno
Summary: In-cell protein crystals that spontaneously crystallize in living cells have been analyzed to understand their structures and biological functions. However, their small size has made it challenging to determine their structures. In this study, the cross-linked network of disulfide bonds within Cry1Aa crystals, a cysteine-rich protein that crystallizes in Bacillus thuringiensis, was characterized through direct X-ray crystallographic analysis using crystals purified from Bt cells.
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
(2023)
