Incorporation of a bromine atom into DNA-related molecules changes their electronic properties

Hirato, Misaki*; Yokoya, Akinari*; Baba, Yuji*; Mori, Seiji*; Fujii, Kentaro*; Wada, Shinichi*; Izumi, Yudai*; Haga, Yoshinori

Physical Chemistry Chemical Physics, 25(21), p.14836 - 14847, 2023/05

https://doi.org/10.1039/D3CP01597A

Secondary structure alterations of histones H2A and H2B in X-irradiated human cancer cells; Altered histones persist in cells for at least 24 hours

Izumi, Yudai; Yamamoto, Satoshi*; Fujii, Kentaro; Yokoya, Akinari

Radiation Research, 184(5), p.554 - 558, 2015/11

https://doi.org/10.1667/RR14071.1

Characteristic oxygen -edge circular dichroism spectra of amino acid films by improved measurement technique

Izumi, Yudai*; Tanabe, Maiko*; Imazu, Akiko*; Mimoto, Aki*; Tanaka, Masahito*; Agui, Akane; Muro, Takayuki*; Nakagawa, Kazumichi*

Journal of Chemical Physics, 138(7), p.074305_1 - 074305_10, 2013/02

https://doi.org/10.1063/1.4790599

no abstracts in English

Measurement and comparison of absolute value of soft X-ray natural circular dichroism of serine and alanine

Izumi, Yudai*; Imazu, Akiko*; Mimoto, Aki*; Tanaka, Masafumi*; Nakagawa, Kazumichi*; Tanaka, Masahito*; Agui, Akane; Muro, Takayuki*

Journal of Physics; Conference Series, 190, p.012209_1 - 012209_4, 2009/11

https://doi.org/10.1088/1742-6596/190/1/012209

Soft X-ray natural circular dichroism spectra of serine and alaninethin films, were measured in absolute value with the focus at the oxygen 1s to transition of COO. The soft X-ray natural circular dichroism spectra intensity of L-Ala was about ten times as large as that of L-Ser. Those differences would reflect the chiral environment of the core hole oxygen atoms of COO.

Destruction of deoxyribose induced by core-ionization

Fujii, Kentaro; Izumi, Yudai; Narita, Ayumi; Yokoya, Akinari; Herv du Penhoat, M.-A.*; Ghose, K.*; Vuilleumier, R.*; Gaigeot, M.-P.*; Politis, M.-F.*

no journal, , 

In order to reveal a role of hydration water on the destruction of dR molecule induced by core electron ionization, we measured a mass spectrum of desorbed ions from the hydrated dR film exposed to soft X-rays with energy above oxygen K-shell ionization threshold (560 eV). The spectral changes of X-ray absorption near edge structure (XANES) of the films after the soft X-ray exposures were also examined the chemical structure of the irradiation products. The yield of the desorbed ions, which were produced by the destruction of furanose ring structure, obviously decreased with depositing one layer of water molecules on the film. This result suggests that the hydration water layer on dR film suppresses an intense destruction of the furanose ring structure of dR induced by the core ionization, or the desorption of the resulting fragment ions from the sample film. We also observed new peaks emerging around 534-536 eV in the XANES spectrum of the hydrated sample irradiated. These new peaks are located at the similar energies to those of XANES peaks of formic acid. The hydration water could also contribute to produce the newly forming products containing a carboxyl group.

Secondary structural changes of chemically modified histones in human cells exposed to X-rays

Yamamoto, Satoshi; Izumi, Yudai; Fujii, Kentaro; Yokoya, Akinari

no journal, , 

no abstracts in English

Roles of hydration for inducing DNA strand breaks by ionization of oxygen K-shell electrons

Fujii, Kentaro; Izumi, Yudai; Krishna, G.*; Pablo, L.-T.*; Alain, T.*; Rodolphe, V.*; Marie-Pierre, G.*; Marie-Francoise, P.*; Marie-Anne, H.*; Yokoya, Akinari

no journal, , 

In order to reveal the role of hydration water regarding ionization the constituent atoms, we measured a mass spectrum of ions desorbing from hydrated deoxyribose (dR) films exposed to monochromatic soft X-rays (560 eV). Desorbing positive ions were detected by a quadrupole mass spectrometer to examine the effect of Coulomb explosion of valence holes produced as a result of Auger decay after the ionization. The yield of desorbing ions which were produced by the destruction of the furanose ring structure of dR, obviously suppressed when one layer of water molecules was deposited onto the film. This result suggests that the hydration water layer on the film inhibits the intense destruction of the furanose induced by the ionization of K-shell electrons of oxygen, or the desorption of the resulting fragment ions from the sample film.

Circular dichroism spectroscopy of amino acid in soft X-ray region

Izumi, Yudai*; Kamohara, Masumi*; Nakagawa, Kazumichi*; Tanaka, Masahito*; Agui, Akane; Muro, Takayuki*; Matsushita, Tomohiro*

no journal, , 

no abstracts in English

Soft X-ray NCD measuremets of His

Izumi, Yudai*; Tanabe, Maiko*; Momoki, Yohei*; Nakagawa, Kazumichi*; Agui, Akane; Muro, Takayuki*

no journal, , 

no abstracts in English

Natural circular dichroism of Asp in soft X-ray region

Izumi, Yudai*; Imazu, Akiko*; Mimoto, Aki*; Tanabe, Maiko*; Nakagawa, Kazumichi*; Tanaka, Masahito*; Agui, Akane; Muro, Takayuki*

no journal, , 

no abstracts in English