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Nakagawa, Hiroshi; Jochi, Yasumasa*; Kitao, Akio*; Yamamuro, Osamu*; Kataoka, Mikio*
Biophysical Journal, 117(2), p.229 - 238, 2019/07
Times Cited Count：3 Percentile：13.03(Biophysics)Softness and rigidity of proteins are reflected in the structural dynamics, which are in turn affected by the environment. The characteristic low-frequency vibrational spectrum of a protein, known as boson peak, is an indication of the structural rigidity of the protein at cryogenic temperature or dehydrated conditions. In this paper, the effect of hydration, temperature, and pressure on the boson peak and volumetric properties of a globular protein are evaluated by using inelastic neutron scattering and molecular dynamics simulation. Hydration, pressurization, and cooling shift the boson peak position to higher energy and depress the peak intensity and decreases the protein and cavity volumes, although pressure hardly affects the boson peak of the fully hydrated protein. A decrease of each volume means the increase of rigidity, which is the origin of the boson peak shift. The boson peak profile can be predicted by the total cavity volume. This prediction is effective for the evaluation of the net quasielastic scattering of incoherent neutron scattering spectra when the boson peak cannot be distinguished experimentally because of a strong contribution from quasielastic scattering.
Ho, D. M. L.*; Nelwamondo, A. N.*; Okubo, Ayako; Rameb
ck, H.*; Song, K.*; Han, S.-H.*; Hancke, J. J.*; Holmgren, S.*; Jonsson, S.*; Kataoka, Osamu; et al.
Journal of Radioanalytical and Nuclear Chemistry, 315(2), p.353 - 363, 2018/02
Times Cited Count：2 Percentile：20.93(Chemistry, Analytical)The Fourth Collaborative Material Exercise (CMX-4) of the Nuclear Forensics International Technical Working Group (ITWG) registered the largest participation for this exercise in nuclear forensics, with seven of the 17 laboratories participating for the first time. In this paper, participants from five of the first-time laboratories shared their individual experience in this exercise, from preparation to analysis of samples. The exercise proved to be highly useful for testing procedures, repurposing established methods, exercising skills, and improving the understanding of nuclear forensic signatures and their interpretation trough the post-exercise review meeting.
Nakagawa, Hiroshi; Kataoka, Mikio; Jochi, Yasumasa*; Kitao, Akio*; Yamamuro, Osamu*
no journal, ,
no abstracts in English
Nakagawa, Hiroshi; Kataoka, Mikio; Jochi, Yasumasa*; Yamamuro, Osamu*; Nakajima, Kenji; Kawamura, Seiko
no journal, ,
Proteins are functional elements in all living organisms. Almost all vital phenomena are mediated by specific proteins. A protein is a hetero-polymer comprised of 20 types of amino acids. The sequence of amino acids of a protein is strictly determined by genetic code. When the polypeptide chain with the amino acid sequence encoded in the gene is biosynthesized, the polypeptide chain folds spontaneously into the unique tertiary structure. The tertiary structure of a protein can be determined by X-ray crystallography. Protein works in an aqueous environment at ambient temperature, indicating that protein cannot escape from thermal fluctuations. In fact, proteins are fluctuating thermally and can take some conformational substates. The magnitude of physiologically relevant input is as the same level as the thermal fluctuations. The understanding of protein dynamics is important to clarify how protein can discriminate physiologically relevant motions from random fluctuation. It is generally recognized that the internal motions of protein is essential for a protein function. Protein internal dynamics is characterized in the time scale of pico - nano second and in the space scale of the order of angstrom. Inelastic neutron scattering (INS) measurement is a powerful and unique technique for studying the protein dynamics. Here, we showed the protein dynamics studies using AGNES and AMATERAS spectrometer, which are installed at JRR-3 and J-PARC, respectively. We will discuss the hydration, temperature and pressure effect on protein dynamics as well as the difference of dynamics between folded and unfolded protein.
Tashiro, Shinsuke; Matsumoto, Tetsuya; Kataoka, Osamu; Amano, Yuki; Abe, Hitoshi; Yamane, Yuichi; Yoshida, Kazuo; Ishikawa, Jun; Uchiyama, Gunzo; Ueda, Yoshinori*; et al.
no journal, ,
Measurements on the release ratios of aerial radioactive materials from mocked fuel reprocessing liquid waste under its boiling to dryness process were performed using labo-scaled experiments. Test sample, dissolved 27 elements into nitric acid and arranged to 2M acidity, was heated up to 300 
C under the constant air ventilation. Steam, gaseous and airborne materials were collected or absorbed at the condenser, the air filter and the washing bottles. The accumulated release ratios of mocked FP elements from samples were determined using ICP-MS. From the accumulated release ratios determined from the condensed samples, the major release of Cs and Ru could be involved the release of mist and gaseous RuO
, respectively. Besides, accumulated release ratios of Ru was about 10 to 1000 times higher than Cs, differed from the literature using fuel reprocessing liquid waste. Its differences could be influenced the nitrous acid, which was reduced the generation of RuO.
Nakagawa, Hiroshi; Jochi, Yasumasa*; Yamamuro, Osamu*; Kataoka, Mikio
no journal, ,
Protein dynamics is closely related with protein biological function. Protein dynamical transition and boson peak is observed by neutron inelastic scattering and molecular dynamics simulation. Protein volume fluctuation is related with cavity in protein structure. The cavity volume is affected by pressure. It is important to examine the effect of pressure on protein dynamics. We examined the effect of pressure on protein dynamical transition and boson peak of Staphylococcal nuclease by neutron inelastic scattering at AGNES spectrometer at JRR-3. We found that boson peak shifted to higher energy upon pressure at 900 MP. And quasi-elastic scattering is restricted by pressure.
Nakagawa, Hiroshi; Jochi, Yasumasa*; Yamamuro, Osamu*; Kataoka, Mikio
no journal, ,
Intrinsically disordered protein (IDP) folds from disordered structure into folded structure upon binding of ligand. In this folding reaction, the structural fluctuation plays an important role for the recognition of target molecules. In the physiological solution, protein stability and dynamics is affected by hydration. It is essential to understand the hydration and dynamics of IDP for elucidation of biological function of IDP. Fragment mutant of Staphylococcal nuclease (SNase) is denatured state at physiological condition and fold upon binding of ligand, therefore, is good model for IDP. We found the difference of dynamics and hydration between folded and unfolded state of SNase by using inelastic neutron scattering experiment.
Tashiro, Shinsuke; Matsumoto, Tetsuya; Kataoka, Osamu; Amano, Yuki; Abe, Hitoshi; Yamane, Yuichi; Yoshida, Kazuo; Ishikawa, Jun; Uchiyama, Gunzo; Ueda, Yoshinori*; et al.
no journal, ,
The release behavior of radioactive materials from high-level radioactive liquid wastes (HLW) from reprocessing plants under an accidents of boiling to dryness of HLW condition has been studied. The influences of FP concentration in the simulated HLW on the release ratio of FP from the waste were measured in the laboratory-scaled experiments using non-radioactive simulated HLW which was prepared by dissolving 27 FP elements into nitric acid and adjusted to 2 M acidity. The simulated HLW was heated up to 300C under the constant air ventilation condition. The accumulated release ratios of FP elements from samples were determined using ICP-MS analysis. It was found that the accumulated release ratio of Ru was decreased with the increase of the initial Ru concentration in the simulated HLW. However, those of Cs and Nd were not influenced by the initial concentrations of them.
Okubo, Ayako; Shinohara, Nobuo; Toda, Nobufumi; Kataoka, Osamu; Matsumoto, Tetsuya
no journal, ,
no abstracts in English
