Shigeki Owada
A5057928846- Advanced X-ray Imaging Techniques
- Particle Accelerators and Free-Electron Lasers
- Advanced Electron Microscopy Techniques and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Photosynthetic Processes and Mechanisms
- Laser-Matter Interactions and Applications
- Photoreceptor and optogenetics research
- Laser-Plasma Interactions and Diagnostics
- Enzyme Structure and Function
- Spectroscopy and Quantum Chemical Studies
- Crystallography and Radiation Phenomena
- Advanced Chemical Physics Studies
- Mass Spectrometry Techniques and Applications
- Ion-surface interactions and analysis
- Light effects on plants
- Magnetic properties of thin films
- Electron and X-Ray Spectroscopy Techniques
- Metal-Catalyzed Oxygenation Mechanisms
- Atomic and Molecular Physics
- Magneto-Optical Properties and Applications
- Laser-induced spectroscopy and plasma
- Laser Material Processing Techniques
- X-ray Diffraction in Crystallography
- Electronic and Structural Properties of Oxides
- Porphyrin and Phthalocyanine Chemistry
SPring-8
2016-2025
Japan Synchrotron Radiation Research Institute
2016-2025
The University of Tokyo
2010-2023
Kyoto University
2015-2023
Tohoku University
2017-2023
RIKEN Center for Advanced Photonics
2015-2023
Optica
2023
Center for Global Health
2023
National Center for Global Health and Medicine
2023
Hokkaido University
2023
Snapshots of bacteriorhodopsin Bacteriorhodopsin is a membrane protein that harvests the energy content from light to transport protons out cell against transmembrane potential. Nango et al. used timeresolved serial femtosecond crystallography at an x-ray free electron laser provide 13 structural snapshots conformational changes occur in nanoseconds milliseconds after photoactivation. These begin active site, propagate toward extracellular side protein, and mediate internal protonation...
In oxygenic photosynthesis, light-driven oxidation of water to molecular oxygen is carried out by the oxygen-evolving complex (OEC) in photosystem II (PS II). Recently, we reported room-temperature structures PS four (semi)stable S-states, S
Abstract In natural photosynthesis, the light-driven splitting of water into electrons, protons and molecular oxygen forms first step solar-to-chemical energy conversion process. The reaction takes place in photosystem II, where Mn 4 CaO 5 cluster stores four oxidizing equivalents, S 0 to intermediate states Kok cycle, sequentially generated by photochemical charge separations center then catalyzes O–O bond formation chemistry 1–3 . Here, we report room temperature snapshots serial...
Abstract Inorganic–organic hybrid materials represent a large share of newly reported structures, owing to their simple synthetic routes and customizable properties 1 . This proliferation has led characterization bottleneck: many are obligate microcrystals with low symmetry severe radiation sensitivity, interfering the standard techniques single-crystal X-ray diffraction 2,3 electron microdiffraction 4–11 Here we demonstrate small-molecule serial femtosecond crystallography (smSFX) for...
Abstract Vision is initiated by the rhodopsin family of light-sensitive G protein-coupled receptors (GPCRs) 1 . A photon absorbed 11- cis retinal chromophore rhodopsin, which isomerizes within 200 femtoseconds to all- trans conformation 2 , thereby initiating cellular signal transduction processes that ultimately lead vision. However, intramolecular mechanism photoactivated induces activation events inside remains experimentally unclear. Here we use ultrafast time-resolved crystallography at...
Photolyases, a ubiquitous class of flavoproteins, use blue light to repair DNA photolesions. In this work, we determined the structural mechanism photolyase-catalyzed cyclobutane pyrimidine dimer (CPD) lesion using time-resolved serial femtosecond crystallography (TR-SFX). We obtained 18 snapshots that show time-dependent changes in four reaction loci. used these results create movie depicts CPD lesions picosecond-to-nanosecond range, followed by recovery enzymatic moieties involved...
Abstract Photosystem II (PSII) catalyses the oxidation of water through a four-step cycle S i states ( = 0–4) at Mn 4 CaO 5 cluster 1–3 , during which an extra oxygen (O6) is incorporated 3 state to form possible dioxygen 4–7 . Structural changes metal and its environment S-state transitions have been studied on microsecond timescale. Here we use pump-probe serial femtosecond crystallography reveal structural dynamics PSII from nanoseconds milliseconds after illumination with one flash (1F)...
The 13th harmonic of a Ti:sapphire (Ti:S) laser in the plateau region was injected as seeding source to 250-MeV free-electron-laser (FEL) amplifier. When amplification conditions were fulfilled, strong enhancement radiation intensity by factor 650 observed. random and uncontrollable spikes, which appeared spectra Self-Amplified Spontaneous Emission (SASE) based FEL without source, found be suppressed drastically form narrow-band, single peak profile at 61.2 nm. properties seeded well...
Phytochrome proteins control the growth, reproduction, and photosynthesis of plants, fungi, bacteria. Light is detected by a bilin cofactor, but it remains elusive how this leads to activation protein through structural changes. We present serial femtosecond X-ray crystallographic data chromophore-binding domains bacterial phytochrome at delay times 1 ps 10 after photoexcitation. The reveal twist D-ring, which partial detachment chromophore from protein. Unexpectedly, conserved so-called...
Significance Understanding ultraintense light–matter interactions is an intriguing subject from viewpoints of basic science and practical applications. For the X-ray region, such research fields have opened up with emergence free-electron lasers (XFELs). By using X-ray–X-ray pump–probe scheme, we firstly measured atomic response to XFEL light femtosecond–ångstrom time–space resolutions. It was found that position freezing until 20 fs after irradiation, which supports feasibility damageless...
We report a method for achieving advanced photon diagnostics of x-ray free-electron lasers (XFELs) under quasi-noninvasive condition by using beam-splitting scheme. Here, we used transmission grating to generate multiple branches beams. One the two primary diffracted (+1st-order) is utilized spectral measurement in dispersive scheme, while other (-1st-order) dedicated arrival timing between XFEL and optical laser pulses. The transmitted beam (0th-order) guided an experimental station. To...
Time-resolved serial femtosecond crystallography using an X-ray free electron laser (XFEL) in conjunction with a photosensitive caged-compound offers crystallographic method to track enzymatic reactions. Here we demonstrate the application of this fungal NO reductase, heme-containing enzyme, at room temperature. Twenty milliseconds after caged-NO photolysis, identify NO-bound form which is initial intermediate slightly bent Fe-N-O coordination geometry resolution 2.1 Å. The compatible those...
The design and performance of a soft X-ray free-electron laser (FEL) beamline the SPring-8 Compact LAser (SACLA) are described. SASE Source test accelerator, prototype machine SACLA, was relocated to SACLA undulator hall for dedicated use FEL beamline. Since accelerator is operated independently main linac that drives two hard beamlines, it possible produce both simultaneously. pulse energy reached 110 µJ at wavelength 12.4 nm (i.e. photon 100 eV) with an electron beam 780 MeV.
An approach is demonstrated to obtain, in a sample- and time-efficient manner, multiple dose-resolved crystal structures from room-temperature protein microcrystals using identical fixed-target supports at both synchrotrons X-ray free-electron lasers (XFELs). This allows direct comparison of serial synchrotron damage-free XFEL femtosecond crystallography radiation-sensitive proteins. Specifically, heme peroxidase enzyme reveal that induced changes occur far lower doses than those which...
Abstract Reversibly switchable fluorescent proteins (RSFPs) serve as markers in advanced fluorescence imaging. Photoswitching from a non-fluorescent off - state to on involves trans -to- cis chromophore isomerization and proton transfer. Whereas excited-state events the ps timescale have been structurally characterized, conformational changes slower timescales remain elusive. Here we describe off-to-on photoswitching mechanism RSFP rsEGFP2 by using combination of time-resolved serial...
Channelrhodopsins (ChRs) are microbial light-gated ion channels utilized in optogenetics to control neural activity with light . Light absorption causes retinal chromophore isomerization and subsequent protein conformational changes visualized as optically distinguished intermediates, coupled channel opening closing. However, the detailed molecular events underlying gating remain unknown. We performed time-resolved serial femtosecond crystallographic analyses of ChR by using an X-ray free...
Bovine cytochrome c oxidase (CcO), a 420-kDa membrane protein, pumps protons using electrostatic repulsion between transferred through water channel and net positive charges created by oxidation of heme (Fe ) for reduction O2 at a3 a3). For this process to function properly, timing is essential: The must be closed after collection the pumped before Fe oxidation. If were remain open, spontaneous backflow collected would occur. elucidation closure mechanism, opening channel, which occurs upon...
Abstract Disentangling the strong interplay between electronic and nuclear degrees of freedom is essential to achieve a full understanding excited state processes during ultrafast nonadiabatic chemical reactions. However, complexity multi-dimensional potential energy surfaces means that this remains challenging. The flow vibrational relaxation can be explored with structural sensitivity by probing wavepacket using femtosecond time-resolved X-ray Absorption Near Edge Structure (TR-XANES). it...
Abstract Despite more than a century of study, the fundamental mechanisms behind solid melting remain elusive at nanoscale. Ultrafast phenomena in materials irradiated by intense femtosecond laser pulses have revived interest unveiling puzzling processes transitions. However, direct experimental validation various microscopic models is limited due to difficulty imaging internal structures undergoing ultrafast and irreversible Here we overcome this challenge through time-resolved single-shot...
Abstract Serial femtosecond crystallography has opened up many new opportunities in structural biology. In recent years, several approaches employing light-inducible systems have emerged to enable time-resolved experiments that reveal protein dynamics at high atomic and temporal resolutions. However, very few enzymes are light-dependent, whereas macromolecules requiring ligand diffusion into an active site ubiquitous. this work we present a drop-on-drop sample delivery system enables the...
Solid-state electrolytes overcome many challenges of present-day lithium ion batteries, such as safety hazards and dendrite formation1,2. However, detailed understanding the involved dynamics is missing due to a lack in operando measurements with chemical interfacial specificity. Here we investigate prototypical solid-state electrolyte using linear nonlinear extreme-ultraviolet spectroscopies. Leveraging surface sensitivity extreme-ultraviolet-second-harmonic-generation spectroscopy,...
Chromophore cis/trans photoisomerization is a fundamental process in chemistry and the activation of many photosensitive proteins. A major task understanding effect protein environment on efficiency direction this reaction compared to what observed gas solution phases. In study, we set out visualize hula twist (HT) mechanism fluorescent protein, which hypothesized be preferred spatially constrained binding pocket. We use chlorine substituent break twofold symmetry embedded phenolic group...