Researchers Database

yamamoto naoki

    PhysiologyMolecularPhysiology&Biophysics Research Associate
Last Updated :2021/12/04

Researcher Information

J-Global ID

Research Areas

  • Natural sciences / Bio-, chemical, and soft-matter physics

Academic & Professional Experience

  • 2018/04 - Today  自治医科大学医学部生理学講座生物物理学部門
  • 2014/06 - 2018/03  Kobe UniversityGraduate School of Science特命助教
  • 2010/04 - 2014/06  Kobe UniversityMolecular Photoscience Research Center

Education

  •        - 2010/03  神戸大学 大学院理学研究科博士課程後期課程化学専攻修了

Published Papers

  • Naoki Yamamoto, Masahiro Nakanishi, Robin Rajan, Hiroshi Nakagawa
    Biophysics and Physicobiology 2021/11 [Refereed]
  • Naoki YAMAMOTO, Eri CHATANI
    Seibutsu Butsuri 61 (4) 236 - 239 0582-4052 2021/07 [Refereed][Invited]
  • Naoki Yamamoto, Maiko Kofu, Kenji Nakajima, Hiroshi Nakagawa, Naoya Shibayama
    The journal of physical chemistry letters 2172 - 2176 2021/02 
    Hydration water plays a crucial role for activating the protein dynamics required for functional expression. Yet, the details are not understood about how hydration water couples with protein dynamics. A temperature hysteresis of the ice formation of hydration water is a key phenomenon to understand which type of hydration water, unfreezable or freezable hydration water, is crucial for the activation of protein dynamics. Using neutron scattering, we observed a temperature-hysteresis phenomenon in the diffraction peaks of the ice of freezable hydration water, whereas protein dynamics did not show any temperature hysteresis. These results show that the protein dynamics is not coupled with freezable hydration water dynamics, and unfreezable hydration water is essential for the activation of protein dynamics. Decoupling of the dynamics between unfreezable and freezable hydration water could be the cause of the distinct contributions of hydration water to protein dynamics.
  • Keisuke Yuzu, Naoki Yamamoto, Masahiro Noji, Masatomo So, Yuji Goto, Tetsushi Iwasaki, Motonari Tsubaki, Eri Chatani
    Biophysical Journal 120 (2) 284 - 295 0006-3495 2020/12 [Refereed]
     
    Amyloid fibrils are aberrant protein aggregates associated with various amyloidoses and neurodegenerative diseases. It is recently indicated that structural diversity of amyloid fibrils often results in different pathological phenotypes, including cytotoxicity and infectivity. The diverse structures are predicted to propagate by seed-dependent growth, which is one of the characteristic properties of amyloid fibrils. However, much remains unknown regarding how exactly the amyloid structures are inherited to subsequent generations by seeding reaction. Here, we investigated the behaviors of self- and cross-seeding of amyloid fibrils of human and bovine insulin in terms of thioflavin T fluorescence, morphology, secondary structure, and iodine staining. Insulin amyloid fibrils exhibited different structures, depending on species, each of which replicated in self-seeding. In contrast, gradual structural changes were observed in cross-seeding, and a new type of amyloid structure with distinct morphology and cytotoxicity was formed when human insulin was seeded with bovine insulin seeds. Remarkably, iodine staining tracked changes in amyloid structure sensitively, and singular value decomposition analysis of the ultraviolet-visible absorption spectra of the fibril-bound iodine has revealed the presence of one or more intermediate metastable states during the structural changes. From these findings, we propose a propagation scheme with multistep structural changes in cross-seeding between two heterologous proteins, which is accounted for as a consequence of the rugged energy landscape of amyloid formation.
  • Takato Hiramatsu, Naoki Yamamoto, Seongmin Ha, Yuki Masuda, Mitsuru Yasuda, Mika Ishigaki, Keisuke Yuzu, Yukihiro Ozaki, Eri Chatani
    Scientific Reports 10 (1) 16741 - 16741 2020/12 [Refereed]
     
    Abstract It is recently suggested that amyloid polymorphism, i.e., structural diversity of amyloid fibrils, has a deep relationship with pathology. However, its prompt recognition is almost halted due to insufficiency of analytical methods for detecting polymorphism of amyloid fibrils sensitively and quickly. Here, we propose that iodine staining, a historically known reaction that was firstly found by Virchow, can be used as a method for distinguishing amyloid polymorphs. When insulin fibrils were prepared and iodine-stained, they exhibited different colors depending on polymorphs. Each of the colors was inherited to daughter fibrils by seeding reactions. The colors were fundamentally represented as a sum of three absorption bands in visible region between 400 and 750 nm, and the bands showed different titration curves against iodine, suggesting that there are three specific iodine binding sites. The analysis of resonance Raman spectra and polarization microscope suggested that several polyiodide ions composed of I3 and/or I5 were formed on the grooves or the edges of β-sheets. It was concluded that the polyiodide species and conformations formed are sensitive to surface structure of amyloid fibrils, and the resultant differences in color will be useful for detecting polymorphism in a wide range of diagnostic samples.
  • Yu Kadomura, Naoki Yamamoto, Keisuke Tominaga
    The European Physical Journal E 42 (10) 1292-8941 2019/10
  • YAMAMOTO Naoki, AKAI Taiki, INOUE Rintaro, SUGIYAMA Masaaki, TAMURA Atsuo, CHATANI Eri
    Biochemistry 58 (24) 2769 - 2781 2019/03 [Refereed][Not invited]
  • Naoki Yamamoto, Shoko Tsuhara, Atsuo Tamura, Eri Chatani
    Scientific Reports 8 (1) 62  2045-2322 2018/12 [Refereed][Not invited]
     
    Non-fibrillar protein aggregates that appear in the earlier stages of amyloid fibril formation are sometimes considered to play a key role in amyloid nucleation however, the structural features of these aggregates currently remain unclear. We herein identified a characteristic pathway of fibril formation by human insulin B chain, in which two major species of prefibrillar aggregates were identified. Based on the time-resolved tracking of this pathway with far-UV circular dichroism (CD) spectroscopy, dynamic light scattering (DLS), and 1H-NMR spectroscopy, the first prefibrillar aggregate with a hydrodynamic diameter of approximately 70 nm accumulated concomitantly with the formation of a β-sheet structure, and the size further evolved to 130 nm with an additional structural development. These prefibrillar aggregates were metastable and survived at least 24 hours as long as they were maintained under quiescent conditions. The energy barrier for nucleation was overcome by shaking or even by applying a single short ultrasonic pulse. Furthermore, an investigation where nucleation efficiency was monitored by fibrillation rates with varying the timing of the ultrasonic-pulse treatment revealed that the second prefibrillar aggregate specifically produced amyloid nuclei. These results suggest that the second form of the prefibrillar aggregates acts as a direct precursor for the amyloid nucleation.
  • Eri Chatani, Naoki Yamamoto
    Biophysical Reviews 10 (2) 527 - 534 1867-2469 2018/04 [Refereed][Not invited]
     
    Amyloid fibrils are supramolecular protein assemblies with a fibrous morphology and cross-β structure. The formation of amyloid fibrils typically follows a nucleation-dependent polymerization mechanism, in which a one-step nucleation scheme has widely been accepted. However, a variety of oligomers have been identified in early stages of fibrillation, and a nucleated conformational conversion (NCC) mechanism, in which oligomers serve as a precursor of amyloid nucleation and convert to amyloid nuclei, has been proposed. This development has raised the need to consider more complicated multi-step nucleation processes in addition to the simplest one-step process, and evidence for the direct involvement of oligomers as nucleation precursors has been obtained both experimentally and theoretically. Interestingly, the NCC mechanism has some analogy with the two-step nucleation mechanism proposed for inorganic and organic crystals and protein crystals, although a more dramatic conformational conversion of proteins should be considered in amyloid nucleation. Clarifying the properties of the nucleation precursors of amyloid fibrils in detail, in comparison with those of crystals, will allow a better understanding of the nucleation of amyloid fibrils and pave the way to develop techniques to regulate it.
  • Naoki Yamamoto, Shota Ito, Masahiro Nakanishi, Eri Chatani, Keiichi Inoue, Hideki Kandori, Keisuke Tominaga
    Journal of Physical Chemistry B 122 (4) 1367 - 1377 1520-5207 2018/02 [Refereed][Not invited]
     
    To investigate the effects of temperature and hydration on the dynamics of purple membrane (PM), we measured the broadband complex dielectric spectra from 0.5 GHz to 2.3 THz using a vector network analyzer and terahertz time-domain spectroscopy from 233 to 293 K. In the lower temperature region down to 83 K, the complex dielectric spectra in the THz region were also obtained. The complex dielectric spectra were analyzed through curve fitting using several model functions. We found that the hydrated states of one relaxational mode, which was assigned as the coupled motion of water molecules with the PM surface, began to overlap with the THz region at approximately 230 K. On the other hand, the relaxational mode was not observed for the dehydrated state. On the basis of this result, we conclude that the protein-dynamical-transition-like behavior in the THz region is due to the onset of the overlap of the relaxational mode with the THz region. Temperature hysteresis was observed in the dielectric spectrum at 263 K when the hydration level was high. It is suggested that the hydration water behaves similarly to supercooled liquid at that temperature. The third hydration layer may be partly formed to observe such a phenomenon. We also found that the relaxation time is slower than that of a globular protein, lysozyme, and the microscopic environment in the vicinity of the PM surface is suggested to be more heterogeneous than lysozyme. It is proposed that the spectral overlap of the relaxational mode and the low-frequency vibrational mode is necessary for the large conformational change of protein.
  • Tsung-Han Liu, Ken-ichi Yuyama, Takato Hiramatsu, Naoki Yamamoto, Eri Chatani, Hiroshi Miyasaka, Teruki Sugiyama, Hiroshi Masuhara
    LANGMUIR 33 (33) 8311 - 8318 0743-7463 2017/08 [Refereed][Not invited]
     
    Femtosecond (fs)-laser-induced crystallization as a novel crystallization technique was proposed for the first time by our group, where the crystallization time can be significantly shortened under fs laser irradiation. Similarly, we have further extended our investigation to amyloid fibril formation, also known as a nucleation-dependence process. Here we demonstrate that the necessary time for amyloid fibril formation can be signifiCantly shortened by fs laser irradiation, leading to favorable enhancement. The enhancement was confirmed by both spectral measurements and direct observations of amyloid fibrils. The thioflavin T fluorescence intensity of laser-irradiated solution increased earlier than that of the control solution, and such a difference was simultaneously revealed by ellipticity changes. At the same time before intensity Saturation in fluorescence, the number of amykid fibrils obtained under laser irradiation was generally mote than that in the control. Solution. Besides, such an enhancement is correlated to the laser power threshold of cavitation bubbling. Possible mechanisms are proposed by referring to fs-laser-induced crystallization and ultrasonication-induced amyloid fibril formation.
  • Naoki Yamamoto, Kaoru Ohta, Atsuo Tamura, Keisuke Tominaga
    JOURNAL OF PHYSICAL CHEMISTRY B 120 (21) 4743 - 4755 1520-6106 2016/06 [Refereed][Not invited]
     
    We have performed dielectric spectral measurements of lysozyme in a solid state to understand the effects of hydration and thermal excitation on the low-frequency dynamics of protein. Dielectric measurements were performed under changing hydration conditions at room temperature in the frequency region of 0.5 GHz to 1.8 THz. We also studied the temperature dependence (83 to 293 K) of the complex dielectric spectra in the THz frequency region (0.3 THz to 1.8 THz). Spectral analyses were performed using model functions for the complex dielectric constant. To reproduce the spectra, we found that two relaxational modes and two underdamped modes are necessary together with an ionic conductivity term in the model function. At room temperature, the two relaxational modes have relaxation times of similar to 20 ps and similar to 100 ps. The faster component has a major spectral intensity and is suggested to be due to coupled water-protein motion. The two underdamped modes are necessary to reproduce the temperature dependence of the spectra in the THz region satisfactorily. The protein dynamical transition is a well-known behavior in the neutron-scattering experiment for proteins, where the atomic mean-square displacement shows a sudden change in the temperature dependence at approximately 200 K, when the samples are hydrated. A similar behavior has also been observed in the temperature dependence of the absorption spectra of protein in the THz frequency region. From our broadband dielectric spectroscopic measurements, we conclude that the increase in the spectral intensities in the THz region at approximately 200 K is due to a spectral blue-shift of the fast relaxational mode.
  • Naoki Yamamoto, Tomoyo Andachi, Atsuo Tamura, Keisuke Tominaga
    JOURNAL OF PHYSICAL CHEMISTRY B 119 (29) 9359 - 9368 1520-6106 2015/07 [Refereed][Invited]
     
    We have studied temperature and hydration dependent low-frequency spectra of lipid bilayers of 1,2-dimyristoyl-sn-glycero-3-phosphoryl-3'-rac-glycerol (DMPG) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) by terahertz time-domain spectroscopy (THz-TDS). We measured X-ray diffraction patterns and mid-infrared spectra of these lipid bilayers and found that the lipid bilayers have two different types of phases, i.e., the gel phase and the crystalline phase, depending on the preparation methods of the samples. In both phases, a few distinct bands were observed in the THz region. For DMPG, the peak wavenumbers of the absorption bands did not change upon hydration, while the bandwidth in the crystalline phase was smaller than that in the gel phase. We performed spectral analyses for the complex dielectric spectra for DMPG and DMPC with a model function, mainly to determine the peak wavenumbers of the absorption bands. In contrast to the case of the DMPG bilayers, the peak wavenumber of the absorption band of the DMPC bilayer shifts upon hydration. In the hydrated DMPC bilayer, it was suggested fast reorienting water molecules exist with a relaxation time of sub-picoseconds. It is suggested that the THz absorption patterns reflect the lipid packing pattern in the bilayers. The temperature dependence of the absorption band was analyzed by an empirical equation, and the anharmonicity of the vibrational potential of the low-frequency mode was quantitatively evaluated.
  • Naoki Yamamoto, Atsuo Tamura
    BIOMACROMOLECULES 15 (2) 512 - 523 1525-7797 2014/02 [Refereed][Not invited]
     
    We have designed a-helical peptides de novo that can induce aggregation of various kinds of cells by focusing on physicochemical properties such as hydrophobicity, net charges, and amphipathicity. It is shown that peptide hydrophobicity is the key factor to determine capabilities for cell aggregation while peptide net charges contribute to nonspecific electrostatic interactions with cells. On the other hand, amphipathic peptides tend to exhibit cytotoxicity such as antimicrobial activity and hemolysis, which are competitive with cell-aggregation capabilities. Different from the cases of living cells, aggregation of artificial anionic liposomes appears to be mainly determined by electrostatic interactions. This discrepancy might be due to the complex structure of surfaces of cell membranes consisting of macromolecular chains such as peptidoglycans, polysaccharides, or glycocalyx, which coexist with lipid bilayers. design peptides that lead aggregation of living cells without cytotoxicity. Our design strategy would pave the Way to design peptides that lead aggregation of living cells without cytotoxicity.
  • Tomoyo Andachi, Naoki Yamamoto, Atsuo Tamura, Keisuke Tominaga
    JOURNAL OF INFRARED MILLIMETER AND TERAHERTZ WAVES 35 (1) 147 - 157 1866-6892 2014/01 [Refereed][Not invited]
     
    We have investigated the low-frequency spectra of a phospholipid bilayer composed of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) by terahertz time-domain spectroscopy (THz-TDS). We focused on the temperature and hydration dependence of the low-frequency spectra of a gel-phase sample. The spectra of the dehydrated and hydrated samples showed shoulder bands at 45 and 30 cm(-1), respectively. In contrast to the dehydrated sample, in the hydrated sample spectra the slope of the temperature change of the absorption coefficient increased sharply around 240 K. This result suggests that water molecules affect the change in the low-frequency dynamics. We obtained the absorption coefficient difference spectra for different hydration levels to clarify the mechanism of the spectral change.
  • Naoki Yamamoto, Ohki Kambara, Kohji Yamamoto, Atsuo Tamura, Shinji Saito, Keisuke Tominaga
    SOFT MATTER 8 (6) 1997 - 2006 1744-683X 2012 [Refereed][Not invited]
     
    We have investigated low-frequency spectra of poly-L-glutamic acid (polyE) in the powder state by terahertz time-domain spectroscopy (THz-TDS). Samples with three different secondary structures (alpha-helix, beta-sheet, and random-coil) and different chain lengths were prepared to investigate the dependence of the THz spectra on temperature and hydration. The temperature dependence of the THz absorption spectra clearly shows that polyE, regardless of its secondary structure, undergoes dynamical transition between 190 and 240 K. We have estimated the apparent activation energy and transition temperature by phenomenological spectral analysis. We also have estimated the effective dipole moment of the amino acid residue from the real part of the dielectric permittivity at zero frequency. Both results show that the transition temperature is lower when the secondary structure undergoes a transition from a random-coil structure to an alpha-helix or beta-sheet structure. Furthermore, both hydrating water molecules and peptide hydrogen bonds contribute to induce anharmonicity in the low-frequency vibrational motions. Meanwhile, hydration, not peptide hydrogen bonds, is crucial for the dynamical transition to occur because the onset of anharmonicity was observed only when the polypeptide is hydrated. An apparent intermolecular vibrational mode in the beta-sheet structure, which suggests a highly ordered structure in the sample, did not exhibit anharmonicity at the tested temperatures and humidity levels. This result suggests that short-range or inter-strand hydrogen bonds of the alpha-helix or low-ordered beta-sheet structures gave rise to the lower transition temperatures and the smaller effective activation energies compared with those of the random-coil structure.
  • Fumi Shima, Yuichi Ijiri, Shin Muraoka, Jingling Liao, Min Ye, Mitsugu Araki, Kousuke Matsumoto, Naoki Yamamoto, Takeshi Sugimoto, Yoko Yoshikawa, Takashi Kumasaka, Masaki Yamamoto, Atsuo Tamura, Tohru Kataoka
    JOURNAL OF BIOLOGICAL CHEMISTRY 285 (29) 22696 - 22705 0021-9258 2010/07 [Refereed][Not invited]
     
    Ras family small GTPases assume two interconverting conformations, "inactive" state 1 and "active" state 2, in their GTP-bound forms. Here, to clarify the mechanism of state transition, we have carried out x-ray crystal structure analyses of a series of mutant H-Ras and M-Ras in complex with guanosine 5'-(beta,gamma-imido) triphosphate (GppNHp), representing various intermediate states of the transition. Crystallization of H-RasT35S-GppNHp enables us to solve the first complete tertiary structure of H-Ras state 1 possessing two surface pockets unseen in the state 2 or H-Ras-GDP structure. Moreover, determination of the two distinct crystal structures of H-RasT35S-GppNHp, showing prominent polysterism in the switch I and switch II regions, reveals a pivotal role of the guanine nucleotide-mediated interaction between the two switch regions and its rearrangement by a nucleotide positional change in the state 2 to state 1 transition. Furthermore, the (31)P NMR spectra and crystal structures of the GppNHp-bound forms of M-Ras mutants, carrying various H-Ras-type amino acid substitutions, also reveal the existence of a surface pocket in state 1 and support a similar mechanism based on the nucleotide-mediated interaction and its rearrangement in the state 1 to state 2 transition. Intriguingly, the conformational changes accompanying the state transition mimic those that occurred upon GDP/GTP exchange, indicating a common mechanistic basis inherent in the high flexibility of the switch regions. Collectively, these results clarify the structural features distinguishing the two states and provide new insights into the molecular basis for the state transition of Ras protein.
  • Naoki Yamamoto, Atsuo Tamura
    PEPTIDES 31 (5) 794 - 805 0196-9781 2010/05 [Refereed][Not invited]
     
    Although several low amphipathic peptides have been known to exhibit antimicrobial activity, their mode of action has not been completely elucidated. In this study, using designed low amphipathic peptides that retain different alpha-helical content and hydrophobicity, we attempted to investigate the mechanism of these properties. Calorimetric and thermodynamic analyses demonstrated that the peptides induce formation of two lipid domains in an anionic liposome at a high peptide-to-lipid ratio. On the other hand, even at a low peptide-to-lipid ratio, they caused minimal membrane damage, such as flip-flop of membrane lipids or leakage of calcein molecules from liposomes, and never translocated across membranes. Interaction energies between the peptides and anionic liposomes showed good correlation with antimicrobial activity for both Escherichia coli and Bacillus subtilis. We thus propose that the domain formation mechanism in which antimicrobial peptides exhibit activity solely by forming lipid domains without membrane damage is a major determinant of the antimicrobial activity of low amphipathic peptides. These peptides appear to stiffen the membrane such that it is deprived of the fluidity necessary for biological functions. We also showed that to construct the lipid domains, peptides need not form stable and cooperative structures. Rather, it is essential for peptides to only interact tightly with the membrane interface via strong electrostatic interactions, and slight differences in binding strength are invoked by differences in hydrophobicity. The peptides thus designed might pave the way for "clean" antimicrobial reagents that never cause release of membrane elements and efflux of their inner components. (C) 2010 Elsevier Inc. All rights reserved.
  • Tomohiro Imamura, Naoki Yamamoto, Atsuo Tamura, Shinji Murabayashi, Shigeki Hashimoto, Hiroaki Shimada, Selichi Taguchi
    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 369 (2) 609 - 615 0006-291X 2008/05 [Refereed][Not invited]
     
    Activity improvement of an antimicrobial peptide, thanatin, has been achieved up to 4-fold higher than natural original one by site-specific chemical modifications with tert-butyl group at two cysteine residues which form an intramoleular disulfide bridge. The chemically modified thanatin (C11tBu/C18tBu) exhibited improved antimicrobial activity toward Gram-positive bacteria, Micrococcus luteus, whereas lowered activity toward Gram-negative bacteria, Escherichia coli. This finding suggests that disulfide-bridge formation is not only indispensable for exhibition of antimicrobial activity of thanatin but also closely related to the activity specificity towards bacteria. NMR analysis indicates that thanatin acts against Ecoli stereospecifically by taking advantage of its C-terminal beta-hairpin structure, while the activity against M. luteus does not relate to structures and correlates very well to side-chain hydrophobicity. (c) 2008 Elsevier Inc. All rights reserved.
  • Jingling Liao, Fumi Shima, Mitsugu Araki, Min Ye, Shin Muraoka, Takeshi Sugimoto, Mei Kawamura, Naoki Yamamoto, Atsuo Tamura, Tohru Kataoka
    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 369 (2) 327 - 332 0006-291X 2008/05 [Refereed][Not invited]
     
    Previous P-31 NMR studies revealed that small GTPases H-Ras and K-Ras in complex with GTP assume two interconverting conformational states, state I and state 2. While state 2 corresponds to an active conformation, little is known about the function of state 1, an inactive conformation incapable of effector binding. To address the biochemical properties of state 1, we measured the P-31 NMR spectra of five Ras family small GTPases; H-Ras, M-Ras, Rap1A, Rap2A and Ra1A, and find that they exhibit distinctive state 2/state 1 populations with the ratios ranging from 0.072 for M-Ras to 16 for Rap2A. Further, we show that GTPases with higher populations of state I exhibit higher dissociation and association rate constants for GTP. These results imply that GTP loading to the nucleotide-free small GTPases preferentially yields state 1, which is subsequently converted to state 2, rendering the GTP-bound form functional. (c) 2008 Elsevier Inc. All rights reserved.

Books etc

  • テラヘルツ時間領域分光による生体高分子の低振動スペクトルの観測 (OplusE 2013年2月号(第399号)
    山本 直樹, 富永 圭介 (Contributor)
    2013/02
  • Temperature and hydration dependence of low-frequency dynamics of two muscle proteins studied by terahertz time-domain spectroscopy
    Naoki Yamamoto, Feng Zhang, Atsuo Tamura, TOMINAGA Keisuke (Others)
    Proceedings of 3rd International THz-Bio Workshop 2012
  • Low-frequency dynamics of functional proteins studied by terahertz time-domain spectroscopy
    Naoki Yamamoto, Feng Zhang, Atsuo Tamura, TOMINAGA Keisuke (Others)
    Proceedings of the conference IRMMW-THz 2011 2011
  • Charge Carrier Dynamics of ZnSe by Optical-Pump Terahertz-Probe Spectroscopy
    Alvin Karlo, G. Tapia, Naoki Yamamoto, Carlito Ponseca Jr, TOMINAGA Keisuke (Others)
    Proceedings of the conference IRMMW-THz 2011 2011

Conference Activities & Talks

  • 弱酸性条件におけるAβ1-40のアミロイド線維形成と膜破壊機構の解明  [Not invited]
    曲師 香緒里, YAMAMOTO NAOKI, 平松 貴人, CHATANI ERI
    第4回 新学術領域研究「動的秩序と機能」若手研究会  2017/11  アイアイランド(大阪府四條畷市)
  • pHおよび塩濃度に依存したトランスサイレチン凝集反応の観察  [Not invited]
    下地 恭平, YAMAMOTO NAOKI, CHATANI ERI
    第4回 新学術領域研究「動的秩序と機能」若手研究会  2017/11  アイアイランド(大阪府四條畷市)
  • Amyloid fibrillation of Aβ1-40 under weak acidic conditions  [Not invited]
    Kaori Mageshi, YAMAMOTO NAOKI, Takato Hiramatsu, CHATANI ERI
    第55回日本生物物理学会年会  2017/09  熊本大学 黒髪北地区
  • 広帯域誘電分光法によるホスホリルコリン基を有する脂質の動的挙動に及ぼす水和の影響  [Not invited]
    門村 友, YAMAMOTO NAOKI, TOMINAGA KEISUKE
    第11回分子科学討論会2017仙台  2017/09  東北大学 川内北キャンパス
  • Investigation of inhibition mechanism of fibrinogen in the amyloid fibrillation  [Not invited]
    Taiki Akai, YAMAMOTO NAOKI, CHATANI ERI
    第55回日本生物物理学会年会  2017/09  熊本大学 黒髪北地区
  • A specific form of prefibrillar aggregates that functions as a precursor of amyloid nucleation  [Not invited]
    YAMAMOTO NAOKI, Shoko Tsuhara, TAMURA ATSUO, CHATANI ERI
    第55回日本生物物理学会年会  2017/09  熊本大学 黒髪北地区
  • 超音波照射によるインスリンB 鎖アミロイド前駆中間体の線維化誘導  [Not invited]
    YAMAMOTO NAOKI, 津原 祥子, TAMURA ATSUO, CHATANI ERI
    第17回日本蛋白質科学会年会  2017/06  仙台国際センター
  • 弱酸性条件におけるAβ1-40アミロイド線維形成反応の観察  [Not invited]
    曲師 香緒里, 平松 貴人, YAMAMOTO NAOKI, CHATANI ERI
    第17回日本蛋白質科学会年会  2017/06  仙台国際センター
  • Protein hydration and its thermal excitation studied by broadband dielectric spectroscopy  [Invited]
    YAMAMOTO Naoki
    The 1st Philippine-Japan Terahertz Research Workshop  2017/02  Laguna, the Philippines
  • Role of prefibrillar intermediates of insulin B chain in its amyloid fibril formation  [Not invited]
    ○Naoki Yamamoto, Shoko Tsuhara, Atsuo Tamura, Eri Chatani
    新学術領域「動的秩序と機能」第5回国際シンポジウム  2017/01  東京大学駒場キャンパス
  • Nucleation dynamics in amyloid formation as investigated by the analysis of prefibrillar intermediates  [Invited]
    ○Eri Chatani, Naoki Yamamoto
    新学術領域「動的秩序と機能」第5回国際シンポジウム  2017/01  東京大学駒場キャンパス
  • A New fibrinogen function of trapping amyloid intermediate conformation  [Not invited]
    ○Taiki Akai, Naoki Yamamoto, Eri Chatani
    新学術領域「動的秩序と機能」第5回国際シンポジウム  2017/01  東京大学駒場キャンパス
  • Protein Hydration Dynamics Studied by Broadband Dielectric Spectroscopy  [Not invited]
    ○Naoki Yamamoto, Shota Ito, Kaoru Ohta, Atsuo Tamura, Eri Chatani, Hideki Kandori, Keisuke Tominaga
    Japan-Taiwan Medical Spectroscopy International Symposium  2016/12  淡路夢舞台国際会議場
  • Investigation of protein aggregation processes leading to amyloid formation  [Not invited]
    ○Eri Chatani, Naoki Yamamoto
    Japan-Taiwan Medical Spectroscopy International Symposium  2016/12  淡路夢舞台国際会議場
  • Molecular Exploration of Prefibrillar Intermediates That Lead to Formation of Amyloid Fibrils  [Invited]
    〇Eri Chatani, Naoki Yamamoto
    Indo-Japan Joint Seminar on "Frontiers in Molecular Spectroscopy: From Fundamentals to Applications on Material Science and Biology"  2016/11  Kanpur (Indo)
  • Hydration and Thermal-Excitation Effects of Purple Membrane Dynamics Probed by Broadband Dielectric Spectroscopy  [Invited]
    〇Naoki Yamamoto, Shota Ito, Eri Chatani, Hideki Kandori, Keisuke Tominaga
    Indo-Japan Joint Seminar on "Frontiers in Molecular Spectroscopy: From Fundamentals to Applications on Material Science and Biology"  2016/11  Kanpur (Indo)
  • Hydration and thermal-excitation effects of purple membrane dynamics probed by broadband dielectric spectroscopy  [Invited]
    YAMAMOTO Naoki
    Indo-Japan Discussion Meeting on Frontiers in Molecular Spectroscopy: From Fundamental to Applications on material science and biology  2016/11  Kanpur, India
  • Fibrinogen inhibits amyloid fibrillation by stopping at the stage of intermediates  [Not invited]
    ○Taiki Akai, Naoki Yamamoto, Eri Chatani
    第54回日本生物物理学会年会  2016/11  つくば国際会議場
  • Effects of hydration on protein dynamics and its thermal excitation studied by broadband dielectric spectroscopy  [Invited]
    YAMAMOTO Naoki
    2nd International Aquaphotomics Symposium  2016/11  神戸
  • 線維前駆中間体に作用点をもつフィブリノーゲンのアミロイド線維化阻害機構  [Not invited]
    赤井 大気, YAMAMOTO NAOKI, CHATANI ERI
    新学術領域研究「動的秩序と機能」第3回若手研究会  2016/10  石川県加賀市
  • 広帯域誘電分光で観るタンパク質ダイナミクスの水和および熱励起効果  [Invited]
    YAMAMOTO NAOKI
    テラヘルツテクノロジーフォーラム 平成28年度 第1回テラヘルツ技術セミナー  2016/10  ホテル北野プラザ六甲荘
  • 広帯域誘電分光で観るタンパク質ダイナミクスの水和および熱励起効果  [Invited]
    YAMAMOTO Naoki
    平成28年度 第1回テラヘルツ技術セミナー「テラヘルツ分子科学の進展」  2016/10  神戸
  • 広帯域誘電分光を用いた紫膜ダイナミクスの観測;サブGHz-THz領域における水和および温度依存性の評価  [Not invited]
    YAMAMOTO NAOKI, 伊藤 奨太, CHATANI ERI, 神取 秀樹, TOMINAGA KEISUKE
    第10回分子科学討論会2016神戸  2016/09  神戸ファッションマート
  • 広帯域分光による水/ジメチルスルホキシド二成分液体中におけるタンパク質の構造安定性  [Not invited]
    飯沼 美紀, YAMAMOTO NAOKI, OHTA KAORU, CHATANI ERI, TOMINAGA KEISUKE
    第10回分子科学討論会  2016/09  神戸ファッションマート
  • H218Oとその同位体の複素誘電率測定と水素結合ダイナミクスに関する理論計算  [Not invited]
    中塚 真莉子, 奧田 真紀, YAMAMOTO NAOKI, OHTA KAORU, 斉藤 真司, TOMINAGA KEISUKE
    第10回分子科学討論会  2016/09  神戸ファッションマート
  • THz分光および広帯域誘電分光による水和タンパク質ダイナミクスの観測  [Invited]
    YAMAMOTO Naoki
    Spring-8シンポジウム 放射光赤外研究会サテライトミーティング「振動分光でわかること:赤外分光の今後と方向性」  2016/08  三田
  • Mechanism of Aβ1-40 fibrillation by the insertion of a single amino-acid residue  [Not invited]
    Kazuto Yamashita, Naoki Yamamoto, Motonari Tsubaki, Eri Chatani
    The 16th Annual Meeting of the Protein Science Society of Japan  2016/06  福岡国際会議場
  • The mechanism of the amyloid fibril formation via prefibrillar intermediates -Characterizing early aggregates formed by insulin B chain-  [Not invited]
    Naoki Yamamoto, Shoko Tsuhara, Atsuo Tamura, Eri Chatani
    The 16th Annual Meeting of the Protein Science Society of Japan  2016/06  福岡国際会議場
  • 広帯域誘電分光法を用いた紫膜のダイナミクスにおける温度および水和依存性の観測  [Not invited]
    YAMAMOTO NAOKI, 伊藤 奨太, CHATANI ERI, 神取 秀樹, TOMINAGA KEISUKE
    第43回生体分子科学討論会2016  2016/06  名古屋大学 野依記念学術交流館  第43回生体分子科学討論会実行委員会
  • Coexisting effects of fibrinogen for amyloid fibril formation  [Not invited]
    Taiki Akai, Naoki Yamamoto, Eri Chatani
    The 16th Annual Meeting of the Protein Science Society of Japan  2016/06  福岡国際会議場
  • タンパク質ダイナミクスにおける水和および熱励起効果の観測 -広帯域誘電分光によるアプローチ  [Invited]
    YAMAMOTO Naoki
    第4回Neutrons in Biology研究会「疾病関連蛋白質の構造・ダイナミクス解析 -疾病発症機構の分子基盤の理解を目指して-」  2016/03  茨城
  • Establishment of E. coli expression system of Aβ1-40 and its purification without reverse-phase column chromatography  [Not invited]
    YAMASHITA KAZUTO, YAMAMOTO NAOKI, TSUBAKI MOTONARI, CHATANI ERI
    BMB2015 (Kobe) 日本生化学会・日本分子生物学会合同年会  2015/12  兵庫県神戸市ポートアイランド
  • ヒトインスリンB鎖を用いたアミロイド線維前駆中間体の捕捉による線維形成機構解明  [Not invited]
    山本 直樹, 津原祥子, CHATANI ERI
    第15回日本蛋白質科学会年会  2015/06  あわぎんホール(徳島市)
  • Temperature and Hydration Dependence ofthe Complex Dielectric spectra of proteins at GHz and THz regions obtained by THz Time-domain spectroscopy and dielectric spectroscopy  [Not invited]
    Naoki Yamamoto, CHATANI ERI, TAMURA ATSUO, TOMINAGA KEISUKE
    AWEST2015  2015/06  淡路夢舞台国際会議場
  • インスリンB鎖におけるアミロイド線維前駆中間体の捕捉と構造特徴の解析(ポスター)  [Not invited]
    CHATANI ERI, 津原 祥子, 山本 直樹, 増田 裕輝
    第62回日本生化学会近畿支部例会  2015/05  立命館大学びわこ・くさつキャンパス
  • インスリンB鎖におけるアミロイド線維前駆中間体の捕捉と構造特徴の解析  [Not invited]
    CHATANI ERI, 津原 祥子, 山本 直樹, 増田 裕輝
    第62回日本生化学会近畿支部例会  2015/05  立命館大学びわこ・くさつキャンパス
  • アミノ酸挿入によるアミロイドβの線維形成への影響  [Not invited]
    山下 和人, YAMAMOTO NAOKI, 鍔木 基成, 茶谷 絵理
    若手フロンティア研究会2014  2014/12
  • Temperature and Hydration Dependence of Complex Dielectric Spectra of Lysozyme from GHz to THz Frequency Region  [Not invited]
    Naoki Yamamoto, Atsuo Tamura, Keisuke Tominaga
    8th International Conference on Broadband Dielectric Spectroscopy and its Applications  2014/09  Wisla (POLAND)
  • Structural investigation of a prefibrillar intermediate of insulin amyloid fibrils  [Not invited]
    Eri Chatani, Hiroshi Imamura, Naoki Yamamoto, Minoru Kato
    The 2nd international symposium of "Dynamical ordering of biomolecular systems for creation of integrated functions"  2014/01  京都
  • Terahertz time-domain spectroscopy on proteins and polypeptides –Effect of thermal activation and hydration on low-frequency dynamics  [Invited]
    Naoki Yamamoto, Azusa Kaneko, Feng Zhang, Atsuo Tamura, TOMINAGA Keisuke
    DAE-BRNS 11th Biennial Trombay Symposium on Radiation & Photochemistry (TSRP 2012)  2012/01  Mumbai, India

MISC

Teaching Experience

  • Lectures on disease-related proteinsLectures on disease-related proteins Jichi Medical University


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