Updated on 2026/03/05
(BLANK) ( Kyoto University )
生物有機化学
放射線化学
光化学
Photochemistry
Bioorganic Chemistry
Radiation Chemistry
Single molecule detection
Nucleic Acids Chemistry
Nanotechnology/Materials / Synthetic organic chemistry
Nanotechnology/Materials / Fundamental physical chemistry
Life Science / Bioorganic chemistry
Nanotechnology/Materials / Structural organic chemistry and physical organic chemistry
Kyoto University Graduate School, Division of Engineering
- 1999
Kyoto University
- 1999
Country： Japan
Kyoto University Faculty of Engineering
- 1994
Kyoto University Faculty of Engineering
- 1994
Country： Japan
Institute of Science Tokyo Department of Life Science and Technology
2024.10
Country：Japan
Tokyo Institute of Technology School of Life Science and Technology Professor
2023.1 - 2024.9
KU-Leuven / imec (Belgium) Visiting Associate Professor
2017.9 - 2018.8
科学技術振興機構 さきがけ研究員（兼任）
2013.10 - 2017.3
Osaka University Associate Professor
2006.4 - 2022.12
Simon Fraser University (Canada) Visiting Associate Professor
2006.1 - 2006.3
Osaka University
2005.10 - 2006.3
Osaka University Research Associate
1999.4 - 2005.9
学術振興会特別研究員
1996 - 1999
光医学・光生物学会
日本放射線化学会
日本化学会
光化学協会
Associate Editor, J. Photochem. Photobiol. C. Photochem. Rev.
2021 - 2022
日本核酸化学会 評議員
2017.11
Committee type：Academic society
日本光医学・光生物学会 第33回日本光医学・光生物学会 事務局長
2011
日本化学会 第90春季年会プログラム編成委員
2010
新世代の生物有機化学研究会 新世代の生物有機化学研究会2008 開催会場責任者
2008
日本化学会 第87春季年会プログラム編成委員
2007
Sensing the Concentration of Biological Reductants through Single-Molecule Fluorescence Blinking Reviewed
Yohei Kondo, Shotaro Tsuchitori, Yuki Yonezawa, Tadao Takada, Atsushi Maruyama, Mamoru Fujitsuka, Kiyohiko Kawai
The Journal of Physical Chemistry Letters 5202 - 5207 2025.5
物質科学動的データに対する機械学習解析 Reviewed
中村 和磨, 小田 勝, 川井 清彦
化学と教育 72 ( 11 ) 460 - 462 2024.11
Programmed Control of Fluorescence Blinking Patterns based on Electron Transfer in DNA
Shuya Fan, Tadao Takada, Atsushi Maruyama, Mamoru Fujitsuka, Kiyohiko Kawai
Chemistry – A European Journal 29 ( 19 ) 2023.2
Zouyue Liu, Hieu Thi Minh Nguyen, Daiki Asanuma, Sachiko Tojo, Minoru Yamaji, Kiyohiko Kawai, Guillem Pratx, Mamoru Fujitsuka, Yasuko Osakada
RSC Advances 13 ( 22 ) 15126 - 15131 2023
Radioluminescence from polymer dots based on thermally activated delayed fluorescence
Daiki Asanuma, Hieu T Nguyen, Zuoyue Liu, Sachiko Tojo, Hajime Shigemitsu, Minoru Yamaji, Kiyohiko Kawai, Tadashi Mori, Toshiyuki Kida, Guillem Pratx, Mamoru Fujitsuka, Yasuko Osakada
Nanoscale Advances 2023
Large heterogeneity observed in single molecule measurements of intramolecular electron transfer rates through DNA
Shuya Fan, Tadao Takada, Atsushi Maruyama, Mamoru Fujitsuka, Kiyohiko Kawai
Bulletin of the Chemical Society of Japan 95 ( 12 ) 1697 - 1702 2022.12
Electron-transfer kinetics through nucleic acids untangled by single-molecular fluorescence blinking
Shuya Fan, Jie Xu, Yasuko Osakada, Katsunori Hashimoto, Kazuya Takayama, Atsushi Natsume, Masaki Hirano, Atsushi Maruyama, Mamoru Fujitsuka, Kumi Kawai, Kiyohiko Kawai
Chem 8 ( 11 ) 3109 - 3119 2022.11
Tadao Takada, Koma Nishida, Yurika Honda, Aoi Nakano, Mitsunobu Nakamura, Shuya Fan, Kiyohiko Kawai, Mamoru Fujitsuka, Kazushige Yamana
ChemBioChem 22 ( 17 ) 2729 - 2735 2021.9
COF-based photocatalyst for energy and environment applications Reviewed
Xinxi Li, Kiyohiko Kawai, Mamoru Fujitsuka, Yasuko Osakada
Surfaces and Interfaces 25 101249 - 101249 2021.8
Jie Xu, Shuya Fan, Lei Xu, Atsushi Maruyama, Mamoru Fujitsuka, Kiyohiko Kawai
Angewandte Chemie International Edition 60 ( 23 ) 12941 - 12948 2021.6
Single-Molecule Study of Redox Reaction Kinetics by Observing Fluorescence Blinking
Kiyohiko Kawai, Mamoru Fujitsuka, Atsushi Maruyama
Accounts of Chemical Research 54 ( 4 ) 1001 - 1010 2021.2
Dynamics of Single‐Stranded RNA Looping Probed and Photoregulated by Sulfonated Pyrene
Jie Xu, Sachiko Tojo, Mamoru Fujitsuka, Kiyohiko Kawai
ChemistrySelect 5 ( 26 ) 8002 - 8008 2020.7
Sulfonated Pyrene as a Photoregulator for Single-Stranded DNA Looping
Jie Xu, Shunichi Miyamoto, Sachiko Tojo, Kiyohiko Kawai
Chemistry - A European Journal 26 ( 22 ) 5075 - 5084 2020.4
Fluorescence Redox Blinking Adaptable to Structural Analysis of Nucleic Acids Reviewed
Takafumi Miyata, Naohiko Shimada, Atsushi Maruyama, Kiyohiko Kawai
Chemistry - A European Journal 24 ( 26 ) 6755 - 6761 2018.5
Kiyohiko Kawai, Takafumi Miyata, Naohiko Shimada, Syoji Ito, Hiroshi Miyasaka, Atsushi Maruyama
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 56 ( 48 ) 15329 - 15333 2017.11
Kiyohiko Kawai, Takafumi Miyata, Naohiko Shimada, Syoji Ito, Hiroshi Miyasaka, Atsushi Maruyama
Angewandte Chemie 129 ( 48 ) 15531 2017.11
Akira Tsuchiya, Siti N. Hashim, Shoko Ise, Takafumi Furuhata, Kiyohiko Kawai, Rie Wakabayashi, Masahiro Goto, Noriho Kamiya, Shinsuke Sando
ANALYTICAL SCIENCES 32 ( 5 ) 543 - 547 2016.5
DNA Microenvironment Monitored by Controlling Redox Blinking Reviewed
Kiyohiko Kawai, Kenji Higashiguchi, Atsushi Maruyama, Tetsuro Majima
CHEMPHYSCHEM 16 ( 17 ) 3590 - 3594 2015.12
Tadao Takada, Misa Ido, Akane Ashida, Mitsunobu Nakamura, Mamoru Fujitsuka, Kiyohiko Kawai, Tetsuro Majima, Kazushige Yamana
CHEMISTRY-A EUROPEAN JOURNAL 21 ( 18 ) 6846 - 6851 2015.4
Increasing the Hole Transfer Rate Through DNA by Chemical Modification Reviewed
Kiyohiko Kawai, Tetsuro Majima
Chemical Science of Electron Systems 751 - 760 2015.1
Photoinduced Charge-Separation in DNA Reviewed
Kiyohiko Kawai, Tetsuro Majima
PHOTOINDUCED PHENOMENA IN NUCLEIC ACIDS II: DNA FRAGMENTS AND PHENOMENOLOGICAL ASPECTS 356 165 - 182 2015
Triple helix conformation-specific blinking of Cy3 in DNA Reviewed
Kiyohiko Kawai, Atsushi Maruyama
CHEMICAL COMMUNICATIONS 51 ( 23 ) 4861 - 4864 2015
Blinking triggered by the change in the solvent accessibility of a fluorescent molecule Reviewed
Kiyohiko Kawai, Takeshi Koshimo, Atsushi Maruyama, Tetsuro Majima
CHEMICAL COMMUNICATIONS 50 ( 72 ) 10478 - 10481 2014
Hole Transfer Kinetics of DNA Reviewed
Kiyohiko Kawai, Tetsuro Majima
ACCOUNTS OF CHEMICAL RESEARCH 46 ( 11 ) 2616 - 2625 2013.11
Kiyohiko Kawai, Tetsuro Majima, Atsushi Maruyama
CHEMBIOCHEM 14 ( 12 ) 1430 - 1433 2013.8
Tadao Takada, Yuta Kawano, Akane Ashida, Mitsunobu Nakamura, Kiyohiko Kawai, Tetsuro Majima, Kazushige Yamana
TETRAHEDRON LETTERS 54 ( 35 ) 4796 - 4799 2013.8
Yasuko Osakada, Kiyohiko Kawai, Tetsuro Majima
Bulletin of the Chemical Society of Japan 86 ( 1 ) 25 - 30 2013
M.J. Park, M. Fujitsuka, K. Kawai, T. Majima
CHEMISTRY-A EUROPEAN JOURNAL 18 ( 24 ) 7326 - 7326 2012.6
Hole Transfer in LNA and 5-Me-2 '-deoxyzebularine-Modified DNA Reviewed
Kiyohiko Kawai, Mitsuo Hayashi, Tetsuro Majima
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 134 ( 22 ) 9406 - 9409 2012.6
HOMO Energy Gap Dependence of Hole-Transfer Kinetics in DNA Reviewed
Kiyohiko Kawai, Mitsuo Hayashi, Tetsuro Majima
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 134 ( 10 ) 4806 - 4811 2012.3
Man Jae Park, Mamoru Fujitsuka, Kiyohiko Kawai, Tetsuro Majima
CHEMISTRY-A EUROPEAN JOURNAL 18 ( 7 ) 2056 - 2062 2012.2
Generation of Singlet Oxygen during Photosensitized One-Electron Oxidation of DNA Reviewed
Yasuko Osakada, Kiyohiko Kawai, Takashi Tachikawa, Mamoru Fujitsuka, Kazuki Tainaka, Shozo Tero-Kubota, Tetsuro Majima
CHEMISTRY-A EUROPEAN JOURNAL 18 ( 4 ) 1060 - 1063 2012.1
Man Jae Park, Mamoru Fujitsuka, Haruhiro Nishitera, Kiyohiko Kawai, Tetsuro Majima
CHEMICAL COMMUNICATIONS 48 ( 89 ) 11008 - 11010 2012
Man Jae Park, Mamoru Fujitsuka, Kiyohiko Kawai, Tetsuro Majima
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 133 ( 39 ) 15320 - 15323 2011.10
Probing the Charge-Transfer Dynamics in DNA at the Single-Molecule Level Reviewed
Kiyohiko Kawai, Eri Matsutani, Atsushi Maruyama, Tetsuro Majima
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 133 ( 39 ) 15568 - 15577 2011.10
G-C Content Independent Long-Range Charge Transfer Through DNA Reviewed
Kiyohiko Kawai, Tetsuro Majima
ELECTRONIC AND MAGNETIC PROPERTIES OF CHIRAL MOLECULES AND SUPRAMOLECULAR ARCHITECTURES 298 129 - 142 2011
Sequence Dependence of Excess Electron Transfer in DNA Reviewed
Kazuki Tainaka, Mamoru Fujitsuka, Tadao Takada, Kiyohiko Kawai, Tetsuro Majima
JOURNAL OF PHYSICAL CHEMISTRY B 114 ( 45 ) 14657 - 14663 2010.11
Kiyohiko Kawai, Haruka Kodera, Tetsuro Majima
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 132 ( 40 ) 14216 - 14220 2010.10
Kiyohiko Kawai, Yasuko Osakada, Eri Matsutani, Tetsuro Majima
JOURNAL OF PHYSICAL CHEMISTRY B 114 ( 31 ) 10195 - 10199 2010.8
Kiyohiko Kawai, Eri Matsutani, Tetsuro Majima
CHEMICAL COMMUNICATIONS 46 ( 19 ) 3277 - 3279 2010
Kinetics of Long-Range Oxidative Electron Transfer through DNA Reviewed
Kiyohiko Kawai, Tetsuro Majima
Radical and Radical Ion Reactivity in Nucleic Acid Chemistry 191 - 210 2009.9
Importance of Protonation State of Guanine Radical Cation During Hole Transfer in DNA Reviewed
Kiyohiko Kawai, Yasuko Osakada, Tetsuro Majima
CHEMPHYSCHEM 10 ( 11 ) 1766 - 1769 2009.8
Sequence-independent and rapid long-range charge transfer through DNA Reviewed
Kiyohiko Kawai, Haruka Kodera, Yasuko Osakada, Tetsuro Majima
NATURE CHEMISTRY 1 ( 2 ) 156 - 159 2009.5
Charge transfer in DNA assemblies: effects of sticky ends Reviewed
Yasuko Osakada, Kiyohiko Kawai, Mamoru Fujitsuka, Tetsuro Majima
CHEMICAL COMMUNICATIONS ( 23 ) 2656 - 2658 2008
Charge transfer through DNA nanoscaled assembly programmable with DNA building blocks Reviewed
Yasuko Osakada, Kiyohiko Kawai, Mamoru Fujitsuka, Tetsuro Majima
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 103 ( 48 ) 18072 - 18076 2006.11
Rapid long-distance hole transfer through consecutive adenine sequence Reviewed
Tadao Takada, Kiyohiko Kawai, Mamoru Fujitsuka, Tetsuro Majima
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 128 ( 34 ) 11012 - 11013 2006.8
Probing the microenvironments in the grooves of Z-DNA using dan-modified oligonucleotides Reviewed
T Kimura, K Kawai, T Majima
CHEMICAL COMMUNICATIONS ( 14 ) 1542 - 1544 2006.4
Spectroscopic Investigation of Oxidative Hole Transfer via Adenine Hopping in DNA Reviewed
Kiyohiko Kawai, Tetsuro Majima
Charge Transfer in DNA: From Mechanism to Application 117 - 132 2006.2
Kiyohiko Kawai, Yasuko Osakada, Mamoru Fujitsuka, Tetsuro Majima
CHEMICAL COMMUNICATIONS ( 37 ) 3918 - 3920 2006
K Osakabe, M Endo, K Kawai, Y Nishizawa, K Ono, K Abe, Y Ishikawa, H Nakamura, H Ichikawa, S Nishimura, T Shimizu, S Toki
MOLECULAR BREEDING 16 ( 4 ) 313 - 320 2005.11
Photosensitized one-electron oxidation of DNA Reviewed
K Kawai, T Majima
PURE AND APPLIED CHEMISTRY 77 ( 6 ) 963 - 975 2005.6
Contributions of the distance-dependent reorganization energy and proton-transfer to the hole-transfer process in DNA Reviewed
T Takada, K Kawai, M Fujitsuka, T Majima
CHEMISTRY-A EUROPEAN JOURNAL 11 ( 13 ) 3835 - 3842 2005.6
Stepwise photocleavage of C-O bonds of bis(substituted-methyl)naphthalenes with stepwise excitation by two-color two-laser and three-color three-laser irradiations. International journal
Xichen Cai, Masanori Sakamoto, Michihiro Hara, Sachiko Tojo, Akihiko Ouchi, Akira Sugimoto, Kiyohiko Kawai, Masayuki Endo, Mamoru Fujitsuka, Tetsuro Majima
The journal of physical chemistry. A 109 ( 17 ) 3797 - 802 2005.5
Recognition of substituted cytosine derivatives by the base pairing with guanine connected to pyrene Reviewed
Kawai, T, Ikegami, M, Kawai, K, Majima, T, Nishimura, Y, Arai, T
CHEMICAL PHYSICS LETTERS 407 ( 1-3 ) 58 - 62 2005.5
Dihydrophenanthrene-type intermediates during photoreaction of trans-4'-benzyl-5-styrylfuran. International journal
Shingo Samori, Michihiro Hara, Tong-Ing Ho, Sachiko Tojo, Kiyohiko Kawai, Masayuki Endo, Mamoru Fujitsuka, Tetsuro Majima
The Journal of organic chemistry 70 ( 7 ) 2708 - 12 2005.4
Inhibition of the formation and decay of stilbene core radical cations by the dendron during the photoinduced electron transfer. International journal
Michihiro Hara, Shingo Samori, Xichen Cai, Sachiko Tojo, Tatsuo Arai, Atsuya Momotake, Junpei Hayakawa, Mayuko Uda, Kiyohiko Kawai, Masayuki Endo, Mamoru Fujitsuka, Tetsuro Majima
The journal of physical chemistry. B 109 ( 2 ) 973 - 6 2005.1
Homolytic cleavage of C-Si bond of p-trimethylsilylmethylacetophenone upon stepwise two-photon excitation using two-color two-laser flash photolysis Reviewed
X. Cai, M. Sakamoto, M. Hara, S. Inomata, M. Yamaji, S. Tojo, K. Kawai, M. Endo, M. Fujitsuka, T. Majima
Chemical Physics Letters 407 ( 4-6 ) 402 - 406 2005
Quenching processes of aromatic hydrocarbons in the higher triplet excited states-energy transfer vs. electron transfer Reviewed
X. Cai, M. Sakamoto, M. Hara, S. Tojo, K. Kawai, M. Endo, M. Fujitsuka, T. Majima
Physical Chemistry Chemical Physics 6 ( 8 ) 1735 - 1741 2004
Two-color two-laser DNA damaging Reviewed
K Kawai, Cai, X, A Sugimoto, S Tojo, M Fujitsitka, T Majima
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 43 ( 18 ) 2406 - 2409 2004
K Kawai, T Majima
LONG-RANGE CHARGE TRANSFER IN DNA I 236 117 - 137 2004
Transient phenomena of polyphenyls in the higher triplet excited state Reviewed
X. Cai, M. Sakamoto, M. Hara, S. Tojo, K. Kawai, M. Endo, M. Fujitsuka, T. Majima
Journal of Physical Chemistry A 108 ( 43 ) 9361 - 9364 2004
Effects of benzyl ether type dendrons as hole-harvesting antennas, and shielding for the neutralization of stilbene core radical cations with chloride ion during two-photon ionization of stilbene dendrimers having stilbene core and benzyl ether type dendr Reviewed International journal
M. Hara, S. Samori, X. Cai, S. Tojo, T. Arai, A. Momotake, J. Hayakawa, M. Uda, K. Kawai, M. Endo, M. Fujitsuka, T. Majima
Journal of the American Chemical Society 126 ( 43 ) 14217 - 14223 2004
Stepwise photocleavage of two C-O bonds of ′1,8-Bis [(4,-benzoylphenoxy)-methyl]naphthalene with three-step excitation using three-color, three-laser flash photolysis Reviewed International journal
X. Cai, M. Sakamoto, M. Hara, S. Tojo, A. Ouchi, K. Kawai, M. Endo, M. Fujitsuka, T. Majima
Journal of the American Chemical Society 126 ( 24 ) 7432 - 7433 2004
Rate constant of bimolecular triplet energy transfer from chrysene in the higher triplet excited states Reviewed
X. Cai, M. Sakamoto, M. Hara, S. Tojo, K. Kawai, M. Endo, M. Fujitsuka, T. Majima
Journal of Physical Chemistry A 108 ( 35 ) 7147 - 7150 2004
Excess electron transfer in DNA studied by pulse radiolysis and gamma-radiolysis of naphthalimide and lodouridine modified ODN Reviewed
K Kawai, T Kimura, K Kawabata, S Tojo, T Majima
JOURNAL OF PHYSICAL CHEMISTRY B 107 ( 46 ) 12838 - 12841 2003.11
Benzophenones in the higher triplet excited states. International journal
Xichen Cai, Masanori Sakamoto, Michihiro Hara, Akira Sugimoto, Sachiko Tojo, Kiyohiko Kawai, Masayuki Endo, Mamoru Fujitsuka, Tetsuro Majima
Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology 2 ( 11 ) 1209 - 14 2003.11
Hole transfer in pyrene-conjugated DNA Reviewed
K Kawai, T Majima
JOURNAL OF SYNTHETIC ORGANIC CHEMISTRY JAPAN 61 ( 6 ) 614 - 619 2003.6
T Takada, K Kawai, S Tojo, T Majima
ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 225 U390 - U390 2003.3
Naphthalene in the higher triplet excited state. Reviewed International journal
Cai X, Hara M, Kawai K, Tojo S, Majima T
Chemical communications (Cambridge, England) ( 2 ) 222 - 223 2003.1
Regulation of one-electron oxidation rate of guanine and hole transfer rate in DNA through hydrogen bonding Reviewed
K Kawai, T Takada, S Tojo, T Majima
TETRAHEDRON LETTERS 43 ( 45 ) 8083 - 8085 2002.11
Regulation of one-electron oxidation rate of guanine by base pairing with cytosine derivatives. Reviewed International journal
Kawai K, Wata Y, Hara M, Tojo S, Majima T
Journal of the American Chemical Society 124 ( 14 ) 3586 - 3590 2002.4
K Kawai, T Takada, S Tojo, T Majima
TETRAHEDRON LETTERS 43 ( 12 ) 2321 - 2321 2002.3
Hole transfer through DNA monitored by transient absorption of phenothiazine radical cation Reviewed
K Kawai, T Takada, S Tojo, T Majima
TETRAHEDRON LETTERS 43 ( 1 ) 89 - 91 2002.1
Selective enhancement of the one-electron oxidation of guanine by base pairing with cytosine Reviewed
K Kawai, Y Wata, N Ichinose, T Majima
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 39 ( 23 ) 4327 - + 2000
8-Methylguanine-containing oligonucleotides: useful structural constraint for Z form DNA. Reviewed
Kawai K, Sugiyama H, Fujimoto K, Saito I
Nucleic acids symposium series ( 34 ) 33 - 34 1995
Hidden Markov simulation for material science dynamic data: Analysis for fluorescence blinking data of DNA
古田達央, 中村和磨, 近藤洋平, 丸山厚, 川井清彦, 高田忠雄, 藤塚守
日本物理学会講演概要集(CD-ROM) 79 ( 1 ) 2024
Kinetics of Photoinduced Reactions at the Single-Molecule Level: The KACB Method
Kiyohiko Kawai, Atsushi Maruyama
Chemistry - A European Journal 26 ( 35 ) 7740 - 7746 2020.6
Long-Range Charge Transfer through DNA by Replacing Adenine with Diaminopurine
Kiyohiko Kawai, Haruka Kodera, Tetsuro Majima
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 132 ( 2 ) 627 - 630 2010.1
Sequence-independent and rapid long-range charge transfer through DNA
Nature Chem. 1 2 156-159 2009
Kinetic Studies of Long-Range Hole Transfer through DNA
2009
Kinetics of charge transfer in DNA containing a mismatch
Yasuko Osakada, Kiyohiko Kawai, Mamoru Fujitsuka, Tetsuro Majima
NUCLEIC ACIDS RESEARCH 36 ( 17 ) 5562 - 5570 2008.10
Mechanism of charge separation in DNA by hole transfer through consecutive adenines
Kiyohiko Kawai, Yasuko Osakada, Mamoru Fujitsuka, Tetsuro Majima
Chemistry - A European Journal 14 ( 12 ) 3721 - 3726 2008.4
Charge separation in acridine- and phenothiazine-modified DNA
Kiyohiko Kawai, Yasuko Osakada, Mamoru Fujitsuka, Tetsuro Majima
Journal of Physical Chemistry B 112 ( 7 ) 2144 - 2149 2008.2
Charge Transfer in DNA
2008
Charge transfer in DNA assembly: effects of sticky end
Chem. Commun. 2656-2658 2008
Charge Separation in Acridine Modified DNA
2008
Charge Separation in Acridine- and Phenothiazine-Modified DNA
J. Phys. Chem. B 112 7 2144-2149 2008
Photocatalytic Cleavage of Single TiO2/DNA Nanoconjugates
Chem. Eur. J. 14 5 1492-1498 2008
Mechanism of Charge-Separation in DNA via Hole Transfer through Consecutive Adenines
Chem. Eur. J. 14 12 3721-13726 2008
Hole Transfer in DNA and Photosensitized DNA Damage: Importance of Adenine Oxidation
2008
Kinetic SNP typing Based on Charge Transfer through DNA
2008
Monitoring G-quadruplex structures and G-quadruplex-ligand complex using 2-aminopurine modified oligonucleotides
Takumi Kimura, Kiyohiko Kawai, Mamoru Fujitsuka, Tetsuro Majima
TETRAHEDRON 63 ( 17 ) 3585 - 3590 2007.4
Hole transfer in DNA and photosensitized DNA damage: Importance of adenine oxidation
Kiyohiko Kawai, Yasuko Osakada, Mamoru Fujitsuka, Tetsuro Majima
JOURNAL OF PHYSICAL CHEMISTRY B 111 ( 9 ) 2322 - 2326 2007.3
Spin-correlated radical pairs in synthetic hairpin DNA
Satoru Nakajima, Kimio Akiyama, Kiyohiko Kawai, Tadao Takada, Tadaaki Ikoma, Tetsuro Majima, Shozo Tero-Kubota
CHEMPHYSCHEM 8 ( 4 ) 507 - 509 2007.3
Charge Separation via Rapid Hole Transfer through Adenine-Hopping
2007
Hole transfer rates in A-form DNA/2′-OMeRNA hybrid
Kiyohiko Kawai, Yasuko Osakada, Akira Sugimoto, Mamoru Fujitsuka, Tetsuro Majima
Chemistry - A European Journal 13 ( 8 ) 2386 - 2391 2007
Hole transfer rates in A-from DNA/2'-OMeRNA hybrid
Chem. Eur. J. 13 8 2386-2391 2007
Monitoring G-Quadruplex Structures and G-Quadruplex-ligand Complex by 2-Aminopurine Modified Oligonucleotide
Tetrahedron 63 17 3585-3590 2007
Hole Transfer in DNA and Photosensitized DNA Damage: Importance of Adenine Oxidation
J. Phys. Chem. B 111 9 2322-2326 2007
Spin-correlated radical pairs in the synthetic hairpin DNA
ChemPhysChem 8 4 507-509 2007
Monitoring of microenvironmental changes in the major and minor grooves of DNA by dan-modified oligonucleotides
Kimura Takumi, Kawai Kiyohiko, Majima Tetsuro
ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 231 2006.3
Formation of pyrene dimer radical cation at the minor groove of DNA
K Kawai, T Kimura, H Yoshida, A Sugimoto, S Tojo, M Fujitsuka, T Majima
BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 79 ( 2 ) 312 - 316 2006.2
Detection of the G-quadruplex-TMPyP4 complex by 2-aminopurine modified human telomeric DNA
T Kimura, K Kawai, M Fujitsuka, T Majima
CHEMICAL COMMUNICATIONS No. 4, pp. 401-402 (2006) ( 4 ) 401 - 402 2006.1
High-yield generation of a long-lived charge-separated state in diphenylacetylene-modified DNA
T Takada, K Kawai, M Fujitsuka, T Majima
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 45 ( 1 ) 120 - 122 2006
Monitoring of microenvironmental changes in the major and minor grooves of DNA by dan-modified oligonucleotides
T Kimura, K Kawai, T Majima
ORGANIC LETTERS 7 ( 26 ) 5829 - 5832 2005.12
Synthesis and properties of terthiophene-modified oligodeoxynucleotides
K Kawai, A Sugimoto, H Yoshida, S Tojo, M Fujitsuka, T Majima
BIOORGANIC & MEDICINAL CHEMISTRY LETTERS 15 ( 20 ) 4547 - 4549 2005.10
Consecutive adenine sequences are potential targets in photosensitized DNA damage
K Kawai, Y Osakada, M Fujitsuka, T Majima
CHEMISTRY & BIOLOGY 12 ( 9 ) 1049 - 1054 2005.9
Kinetics of transient end-to-end contact of single-stranded DNAs
K Kawai, H Yoshida, A Sugimoto, M Fujitsuka, T Majima
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 127 ( 38 ) 13232 - 13237 2005.9
Selective guanine oxidation by UVB-irradiation in telomeric DNA
K Kawai, M Fujitsuka, T Majima
CHEMICAL COMMUNICATIONS No. 11, pp. 1476-1477 (2005)/, ( 11 ) 1476 - 1477 2005
Photocatalytic oxidation reactivity of holes in the sulfur- and carbon-doped TiO2 powders studied by time-resolved diffuse reflectance spectroscopy
T Tachikawa, S Tojo, K Kawai, M Endo, M Fujitsuka, T Ohno, K Nishijima, Z Miyamoto, T Majima
JOURNAL OF PHYSICAL CHEMISTRY B 108 ( 50 ) 19299 - 19306 2004.12
Lifetime regulation of the charge-separated state in DNA by modulating the oxidation potential of guanine in DNA through hydrogen bonding
K Kawai, Y Osakada, T Takada, M Fujitsuka, T Majima
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 126 ( 40 ) 12843 - 12846 2004.10
Formation of pyrene dimer radical cation at the internal site of oligodeoxynucleotides
K Kawai, H Yoshida, T Takada, S Tojo, T Majima
JOURNAL OF PHYSICAL CHEMISTRY B 108 ( 35 ) 13547 - 13550 2004.9
Direct observation of hole transfer through double-helical DNA over 100 A
T Takada, K Kawai, M Fujitsuka, T Majima
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 101 ( 39 ) 14002 - 14006 2004.9
Formation and Decay of Pyrene Radical Cation and Pyrene Dimer Radical Cation in the Absence and Presence of Cyclodextrins during Resonant Two－Photon Ionization of Pyrene and Sodium 1-Pyrene Sulfonate Reviewed
Michihiro Hara, Sachiko Tojo, Kiyohiko Kawai, Tetsuro Majima
Physical Chemistry Chemical Physics 6 ( 13 ) 3215 - 3220 2004.6
Fluorescence properties of 2-aminopurine in human telomeric DNA
T Kimura, K Kawai, M Fujitsuka, T Majima
CHEMICAL COMMUNICATIONS No. 12, pp. 1438 - 1439/, ( 12 ) 1438 - 1439 2004.6
Charge separation in DNA via consecutive adenine hopping
T Takada, K Kawai, XC Cai, A Sugimoto, M Fujitsuka, T Majima
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 126 ( 4 ) 1125 - 1129 2004.2
Fluorescence properties of 2-aminopurine-cytidine-7-deazaguanine (5 '-ApC(dz)G-3 ') trimer in B- and Z-DNA
T Kimura, K Kawai, T Majima
CHEMICAL COMMUNICATIONS ( 3 ) 268 - 269 2004.2
One-electron attachment reaction of B- and Z-DNA modified by 8-bromo-2 '-deoxyguanosine
T Kimura, K Kawai, S Tojo, T Majima
JOURNAL OF ORGANIC CHEMISTRY 69 ( 4 ) 1169 - 1173 2004.2
Effects of interaction of photosensitizer with DNA and stacked G bases on photosensitized one-electron oxidation of DNA
T Takada, K Kawai, S Tojo, T Majima
JOURNAL OF PHYSICAL CHEMISTRY B 108 ( 2 ) 761 - 766 2004.1
Hole transfer in DNA by monitoring the transient absorption of radical cations of organic molecules conjugated to DNA
K Kawai, T Majima
LONG-RANGE CHARGE TRANSFER IN DNA I 236 117 - 137 2004
Kinetics of multistep hole transfer in DNA by monitoring the transient absorption of the pyrene radical cation
T Takada, K Kawai, S Tojo, T Majima
JOURNAL OF PHYSICAL CHEMISTRY B 107 ( 50 ) 14052 - 14057 2003.12
Long-lived charge-separated state leading to DNA damage through hole transfer
K Kawai, T Takada, T Nagai, XC Cai, A Sugimoto, M Fujitsuka, T Majima
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 125 ( 52 ) 16198 - 16199 2003.12
Some triplet energy-transfer re actions initiated by photo-excitation of triplet excited state of dibenz[a h]anthracene to the higher triplet excited states Reviewed
Xichen Cai Michihiro Hara, Kiyohiko Kawai, Sachiko Tojo, Mamoru Fujitsuka, Tetsuro Majima
Tetrahedron Letters 44 ( 32 ) 6117 - 6120 2003.8
Kinetics of weak distance-dependent hole transfer in DNA by adenine-hopping mechanism
K Kawai, T Takada, S Tojo, T Majima
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 125 ( 23 ) 6842 - 6843 2003.6
Hole transfer in DNA: DNA as a scaffold for hole transfer between two organic molecules
T Takada, K Kawai, S Tojo, T Majima
TETRAHEDRON LETTERS 44 ( 19 ) 3851 - 3854 2003.5
Sensitized reactions by Benzophenone in the Higher Triplet Excited State Reviewed
Xichen Cai Michihiro Hara, Kiyohiko Kawai, Sachiko Tojo, Tetsuro Majima
Chemical Physics Letters 371 ( 1-2 ) 68 - 73 2003.3
Efficient C2 'alpha-hydroxylation of deoxyribose in protein-induced Z-form DNA
T Oyoshi, K Kawai, H Sugiyama
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 125 ( 6 ) 1526 - 1531 2003.2
Formation of pyrene dimer radical cation in DNA reflecting DNA dynamics in the time range of 1 mu s to 1 ms
K Kawai, K Miyamoto, S Tojo, T Majima
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 125 ( 4 ) 912 - 915 2003.1
Properties of chrysene in the higher triplet excited state Reviewed
Xichen Cai Michihiro Hara, Kiyohiko Kawai, Sachiko Tojo, Tetsuro Majima
Chemical Physics Letters 368 ( 3-4 ) 365 - 369 2003.1
Excess Electron Transfer in DNA Studied by Pulse Radiolysis and γ-Radiolysis of Naphthalimide and Iodouridine Containing ODN
KAWAI K, KIMURA T, KAWABATA K, TOJO S, MAJIMA T
J. Phys. Chem. B 107/46, 12838-12841 (2003). 107 ( 46 ) 12838 - 12841 2003
Effects of base pairing on the one-electron reduction rate of cytosine
K Kawai, A Yokoohji, S Tojo, T Majima
CHEMICAL COMMUNICATIONS 2840-2841 ( 22 ) 2840 - 2841 2003
Synthesis of ODNs containing 4-methylamino-1,8-naphthalimide as a fluorescence probe in DNA
K Kawai, K Kawabata, S Tojo, T Majima
BIOORGANIC & MEDICINAL CHEMISTRY LETTERS 12 ( 17 ) 2363 - 2366 2002.9
Pulse Radiolytic Study of Hole Transfer in DNA
KAWAI Kiyohiko, MAJIMA Tetsuro
73 28 - 31 2002.3
Effect of hydrogen bonding on the photo-oxidation of DNA
Kiyohiko Kawai, Tetsuro Majima
Journal of Photochemistry and Photobiology C: Photochemistry Reviews 3 ( 1 ) 53 - 66 2002
Observation of hole transfer through DNA by monitoring the transient absorption of pyrene radical cation
K Kawai, T Takada, S Tojo, N Ichinose, T Majima
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 123 ( 50 ) 12688 - 12689 2001.12
Enhancement of One-Electron Oxidation of Guanine by Base-Pairing with Cytosine
Proceedings of the 4th SANKEN International Symposium on Biological Molecular Machines and Bio-devices, pp.~77-78 pp.~77-78 2001
Hydrogen Bonding Modulation of Electron Transfer Rate of DNA
Proceedings of the 4th International Symposium on InterMaterial, p.~79 p.~79 2001
Hole Transfer in DNA
Proceedings of the 4th SANKEN International Symposium on Biological Molecular Machines and Bio-devices, pp.~79-80 pp.~79-80 2001
Selective enhancement of the one-electron oxidation of guanine by base pairing with cytosine
Kiyohiko Kawai, Yasuharu Wata, Nobuyuki Ichinose, Tetsuro Majima
Angewandte Chemie - International Edition 39 ( 23 ) 4327 - 4329 2000.12
Selective Enhancement of One-Electron Oxidation of Guanine by Base-Pairing with Cytosine
Angew.~Chem.~Int.~Ed.~Eng., Vol.~39, No.~23, pp.~4327-4329 Vol.~39, No.~23, pp.~4327-4329 2000
Charge Transfer in DNA
Abstracts of COE: Third International Symposium on Atomic Scale Processing and Novel Properties in Nanoscopic Materials, p.~108 p.~108 2000
Effect of Base-Pairing on One-Electron Oxidation of Guanine
Proceedings of the 3rd SANKEN International Symposium on Advanced Nanoelectronics: Materials, Devices and Computing, pp.~189-190 pp.~189-190 2000
One-electron Oxidation of DNA
Abstracts of the 8th Japan-China Bilateral Symposium on Photochemistry, pp.~121-122 pp.~121-122 2000
Enhancement of One-Electron Oxidation of Guanine by Base-Pairing with Cytosine
Abstracts of the 2000 International Chemical Congress of Pacific Basin Societies (PACIFICHEM 2000), p.~ORGN 9, Paper 144 9, Paper 144 2000
Pulse Radiolytic Study of Charge Transport through DNA
Abstracts of the satellite symposium of the International Symposium on Prospect for Application of Radiation towards the 21st Century, p.~46 p.~46 2000
Charge Transfer in DNA
Abstracts of COE: Third International Symposium on Atomic Scale Processing and Novel Properties in Nanoscopic Materials, p.~20 p.~20 2000
Enhancement of One-Electron Oxidation of Guanine by Base-Pairing with Cytosine
Abstracts of the 2000 International Chemical Congress of Pacific Basin Societies (PACIFICHEM 2000), p.~ORGN 9, Paper 144 9, Paper 144/, 2000
Controlling the Electron Transfer Rate by the Hydrogen-Bond of DNA Monomer
Abstracts of COE: Third International Symposium on Atomic Scale Processing and Novel Properties in Nanoscopic Materials, p.~109 p.~109 2000
分子スケールの光論理ゲートの集積
川井 清彦, 真嶋 哲朗
光化学 = Photochemistry 30 ( 2 ) 142 - 143 1999.8
Photochemical halogen-exchange reaction of 5-iodouracil-containing oligonucleotides
K Kawai, Saito, I, H Sugiyama
TETRAHEDRON LETTERS 40 ( 31 ) 5721 - 5724 1999.7
Intrastrand 2'β hydrogen abstraction of 5'-adjacent deoxyguanosine by deoxyuridin-5-yl in Z-form DNA
Kiyohiko Kawai, Isao Saito, Etsuko Kawashima, Yoshiharu Ishido, Hiroshi Sugiyama
Tetrahedron Letters 40 ( 13 ) 2589 - 2592 1999.3
Conformation-dependent photochemistry of 5-halouracil-containing DNA: Stereospecific 2 'alpha-hydroxylation of deoxyribose in Z-form DNA
K Kawai, Saito, I, H Sugiyama
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 121 ( 6 ) 1391 - 1392 1999.2
Conformation Dependent Photochemistry of 5-Halouracil Containing DNA : Stereo-Specific 2'α-Hydroxylation of Deoxyribose in Z-form DNA.
J. Am. Chem. Soc. 121 ( 6 ) 1391 - 1392 1999
Conformation Dependent Photochemistry of 5-Halouracil Containing DNA: Stereospecific 2'a-Hydroxylation of Deoxyribose in Z-form DNA
121, 1391-1392 1999
Construction of Molecular-scale Photologic Gates
Vol.~30, No.~2, pp.~142-143 1999
Construction of Molecular-scale Photologic Gates
Vol.~30, No.~2, pp.~142-143/, 1999
Stabilization of Hoogsteen base pairing by introduction of NH2 group at the C8 position of adenine
K Kawai, Saito, I, H Sugiyama
TETRAHEDRON LETTERS 39 ( 29 ) 5221 - 5224 1998.7
Conformation Dependent Photochemistry of 5-Halouracil Containing DNA : Specific ribose 2'-hydroxylation in Z-form DNA.
Nucleic Acids Symp. Ser. 39 99 - 100 1998
Photoreaction of 5-halouracil-containing Z-form DNA.
K Kawai, H Sugiyama, Saito, I
ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 214 103 - ORGN 1997.9
Photoreaction of 5-Halouracil-Containing Z-form DNA.
Photomedicine and Photobiology 19 95 - 97 1997
Photoreaction of 5-halouracil-containing Z-form DNA.
Nucleic Acids Symp. Ser. 37 93 - 94 1997
Synthesis, structure and thermodynamic properties of 8-methylguanine-containing oligonucleotides: Z-DNA under physiological salt conditions
H Sugiyama, K Kawai, A Matsunaga, K Fujimoto, Saito, I, H Robinson, AHJ Wang
NUCLEIC ACIDS RESEARCH 24 ( 7 ) 1272 - 1278 1996.4
Effects of methylation on B-to Z-DNA transition.
Nucleic Acids Symp. Ser 35 87 - 88 1996
Photoreactivity of BrU-Conaining Oligonucleotides in Z-form.
川井清彦, 藤本健造, 杉山弘, 斎藤烈
日本化学会講演予稿集 70th ( 2 ) 1996
Regulation of B-Z Transition by Introduction of 8-Methyldeoxyguanosine.
川井清彦, 藤本健造, 松永篤, 杉山弘, 斎藤烈
日本化学会講演予稿集 69th ( 2 ) 1995
Synthesis of Oligonucleotides Containing 8-Methyldeoxyguanosine and Their Photoreactivity.
杉山弘, 藤本健造, 松永篤, 川井清彦, 斎藤烈
日本化学会講演予稿集 67th ( 2 ) 1994
The Japanese Photochemistry Association Award
2021.9 The Japanese Photochemistry Association Single-molecule photochemistry of nucleic acids and its application to single-molecule analysis and diagnosis
大阪大学総長奨励賞
2015.7 大阪大学
川井 清彦
大阪大学総長奨励賞
2014.7 大阪大学
川井 清彦
BCSJ賞
2013.1 日本化学会
川井 清彦
ISNAC Outstanding Oral Presentation Award in 2011
2011.11 International Symposium on Nucleic Acids Chemistry (ISNAC)
KAWAI Kiyohiko
The Japanese Photochemistry Association Prize for Young Scientist for 2008
2008
第86回春季年会優秀講演賞
2006.3 日本化学会
川井 清彦
日本光医学・光生物学会 奨励賞
2001
蛍光ブリンキング制御による細胞内粘度・拡散速度の超解像計測
Grant number：24K01624 2024.4 - 2027.3
日本学術振興会 科学研究費助成事業 基盤研究(B)
川井 清彦, 丸山 厚, 田邉 一仁
Grant amount：\18590000 （ Direct Cost: \14300000 、 Indirect Cost：\4290000 ）
Integrated understanding and manipulation of hypoxic cellular functions by artificial nucleic acids with hypoxia-accumulating properties
Grant number：23K26779 2023.4 - 2026.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
Grant amount：\19110000 （ Direct Cost: \14700000 、 Indirect Cost：\4410000 ）
RNAダイナミクスの学理構築とRNA標的薬剤アッセイ系の構築
Grant number：21H02059 2021.4 - 2024.3
日本学術振興会 科学研究費助成事業 基盤研究(B)
川井 清彦, 田邉 一仁
Grant amount：\17420000 （ Direct Cost: \13400000 、 Indirect Cost：\4020000 ）
2021年度は、RNA構造転移の測定法の１つとして、三重項－三重項エネルギー移動を利用した、RNA構造転移の測定法の開発に取り組んだ。一重項－一重項エネルギー移動であるFRETでは、一般にエネルギードナー、アクセプター間の距離が50Å程度以上変化する大きな構造転移の観測に優れている。これに対し、三重項－三重項エネルギー移動では、ドナー、アクセプター間の衝突が必要であるため、ドナー、アクセプターが衝突するRNAの分子運動に絞って追跡できる。ここで、1分子蛍光観察特有の現象であるblinkingを利用し、蛍光相関解析から三重項－三重項エネルギー移動が起こるのに要する時間（τT）を求める（1/τT はRNA分子運動速度に対応）。アクセプターとしては1,4,5,8-cyclooctatetraene（COT）を用いる。COTは、三重項－三重項エネルギー移動によりエネルギーを受け取り、100 μs以内にそのエネルギーを熱として放出し、蛍光分子の光安定性を向上させることが報告されている。蛍光分子としてATTO 647N、市販のCOTアミダイト誘導体を用いて、DNAをプラットフォームとしてblinkingにより三重項－三重項エネルギー移動の観測を試みたところ、τTがATTO 647NとCOT間の1本鎖DNAスペーサが長くなるほど長くなった。また、DNAスペーサがより柔軟なポリTの時に、より剛直なポリAと比べτTが長くなり、τTがDNAの1本鎖ダイナミクスにより起こるATTO 647NとCOTの分子衝突に要する時間を反映している、すなわち、τTの測定により核酸の構造転移を観測できることが示された。
Elucidation of the mechanism of mutagenesis by transient nucleobase adducts
Grant number：19K22256 2019.6 - 2022.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Research (Exploratory)
KAWAI KIYOHIKO
Grant amount：\6370000 （ Direct Cost: \4900000 、 Indirect Cost：\1470000 ）
In this study, we aimed to gain insight into the formation of N2-ethylidene-G (ethG), a nucleic acid adduct transiently induced in the body by the ingestion of alcohol, a carcinogen. Using PacBio's RSII+ next-generation sequencer, we have successfully observed the formation of ethG in the presence of relatively high concentrations of acetaldehyde on the order of mM by tracking single molecules of the binding and dissociation processes of nucleic acids. The results of this study highlight the need for appropriate processing of large amounts of data in order to discuss the formation of ethG in detail and quantitatively. In order to establish a data analysis method for the formation and dissociation process of transiently formed ethG, single molecule analysis of nucleic acid aptamers was achieved.
DNA高次構造転移の1分子実時間観測
2017.4 - 2020.3
日本学術振興会 科研費 基盤研究（B）
川井 清彦
Authorship：Principal investigator Grant type：Competitive
RNA1分子検出による癌の遺伝子点突然変異診断
2017.4 - 2019.3
キヤノン財団 研究助成プログラム「産業基盤の創生」
川井 清彦
Authorship：Principal investigator Grant type：Competitive
弱い過渡的相互作用をトリガーとしたRNAの1分子イメージング
2016.4 - 2018.3
日本学術振興会 科研費 新学術領域（共鳴誘導で革新するバイオイメージング）
川井 清彦
Authorship：Principal investigator Grant type：Competitive
DNA超らせんダイナミクスの1分子レベル解析
2014.4 - 2016.3
日本学術振興会 科研費 挑戦的萌芽研究
川井 清彦
Authorship：Principal investigator Grant type：Competitive
蛍光のblinkingを自在に操る分子技術の創出
2013.10 - 2017.3
独立行政法人科学技術振興機構 さきがけ「分子技術と新機能創出」領域
川井 清彦
Authorship：Principal investigator Grant type：Competitive
RNAの編集、化学修飾情報の1分子レベル解析技術の開発
2012.4 - 2015.3
日本学術振興会 科研費 基盤研究（B）
川井 清彦
Authorship：Principal investigator Grant type：Competitive
らせんねじれ角およびＨＯＭＯギャップ改変によるＤＮＡ分子ワイヤーの構築
Grant number：23108711 2011.4 - 2013.3
日本学術振興会 科学研究費助成事業 新学術領域研究(研究領域提案型)
川井 清彦
Grant amount：\4680000 （ Direct Cost: \3600000 、 Indirect Cost：\1080000 ）
種々のHOMOレベルを有する、天然および修飾核酸塩基を用いて、同一鎖上の核酸塩基間のHOMOレベルギャップがDNA内ホール移動速度に与える影響を調べた。GからGのホール移動において、介在するブリッジ塩基のHOMOレベルを様々に変化しホール移動速度を測定した。ホール移動速度は、HOMOギャップの減少に伴い高速化することがわかった。また、HOMOレベルギャップを調節することにより、DNA内ホール移動速度を3桁にわたり制御可能であることが示された。このように、核酸塩基間のHOMOギャップ縮小によりDNA内ホール移動の高速化が可能であることが明らかになった。
核酸塩基のπ平面の重なりが大きいほどホール移動速度が速くなることが示唆されていた。DNAはらせんを形成する際、塩基対ごとに約35度のねじれを生じ、結果として塩基間のπスタッキング面積の減少をまねいている。修飾核酸の一つであるLocked Nucleic Acid（LNA）は、糖部位のコンフォメーションが3'-endoに固定された構造をとり、結果としてらせん角が通常のB型DNAの約35度から約26度へと減少し、πスタッキング面積が増加する。一方、LNA修飾によりDNAの構造がより剛直化することが報告されていた。DNA内ホール移動速度はLNA修飾により低下し、11塩基対をLNA置換するとホール移動速度が100倍以上減少することがわかった。次にG-C塩基対の水素結合数を減らし、核酸をより柔軟にする5-Me-2'-deoxyzebularine（B）がDNA中のホール移動速度に与える影響を調べた。シトシンをBに置換すると、ホール移動速度が20倍以上増加することがわかった。以上の結果から、DNA内をホールが移動するためにはDNAの分子運動が必須であり、DNAの柔軟化によってホール移動を高速化可能であることが示された。
Monitoring the function of molecular beacon type probe at the single molecule level
Grant number：23655155 2011 - 2012
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
KAWAI Kiyohiko
Grant amount：\4030000 （ Direct Cost: \3100000 、 Indirect Cost：\930000 ）
DNA site specifically modified with fluorescent molecule were synthesized. The lifetime of a fluorescent molecule in the triplet excited state was measured, which is reflected in the duration of the off time during the blinking of the fluorescence (tOFF). tOFF was determined by fluorescence correlation spectroscopy (FCS). It was demonstrated that the more a fluorescent molecule is exposed to a solvent, the faster its triplet excited state is quenched by molecular oxygen, resulting in a decrease of tOFF. DNA conformational change between a duplex and hairpin structure, function of the molecular beacon type probe, was successfully monitored by the blinking triggered by the changes in the solvent accessibility of the fluorescent molecule.
Higher Excited State Chemistry Towards Molecular Device, Environmental Chemistry, and Nano- and Biotechnologies
Grant number：22245022 2010 - 2012
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
MAJIMA Tetsuro, FUJITSUKA Mamoru, KAWAI Kiyohiko, TACHI KAWA Takashi
Grant amount：\48490000 （ Direct Cost: \37300000 、 Indirect Cost：\11190000 ）
The present research project aimed at application of higher excited state chemistry to molecular devices, environmental problem, and nano- and bio-technologies. Reaction processes through the higher excited states were investigated by various ultrafast spectroscopic methods and radiation chemical methods. The main achievements of this research project are clarification of ultrafast structural relaxation processes in the excited state, understandings of reaction processes from the excited radical ions, estimation of dynamics of excess electron in DNA, and so on.
Reading out the DNA sequence information by measuring the lifetime of the charge separated state
Grant number：21750170 2009 - 2010
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)
KAWAI Kiyohiko
Grant amount：\4550000 （ Direct Cost: \3500000 、 Indirect Cost：\1050000 ）
Charge-separation and charge recombination in DNA was established using the fluorescent dyes those absorbs in the visible region. The lifetime of the charge-separated state was significantly affected by the surrounding sequences which enabled the read out the DNA sequence information based on the measurement of the lifetime of the charge separated state.
DNAナノ光電荷分離システムの構築
Grant number：18750148 2006 - 2007
日本学術振興会 科学研究費助成事業 若手研究(B)
川井 清彦
Grant amount：\3600000 （ Direct Cost: \3600000 ）
我々はこれまで、光増感剤としてナフタルイミドを用いることによりDNA内電荷分離状態の生成に成功してきた。しかしながら、光照射により強い酸化力を有するナフタルイミドを用いた場合、無差別にすべての塩基を酸化してしまうため近接塩基上にホールが発生し素早い逆電子移動が起こり電荷分離収率は数パーセント程度にとどまった。また、ナフタルイミドを用いる場合では紫外光照射が必要であり、太陽光エネルギー変換への応用が困難であった。本課題では、より太陽光を収集しやすい可視領域に強い吸収体を有し、酸化力が強すぎず、特定の核酸塩基のみを酸化可能なアクリジンなどを光増感剤(集光アンテナ)として用いることによる電荷分離システムの構築を目指した。長寿命の電荷分離状態を達成するためには、電子とホールを十分に引き離す必要がある。ここで、DNA2本鎖をホールの通り道として利用するが、逆電子移動を最小限にするため、市販されている種々の酸化電位を有する修飾核酸塩基を酸化電位の順に配列させ電荷が一方向に流れるよう検討を行った。設計、合成したDNAはすでに構築済みであるHPLCシステムを利用して精製し、UV融解温度測定(T_m測定)によりその構造の安定性を調べ、ナノ秒レーザーフォトリシスシステムを用いることによりその電荷分離の量子収率を評価した。その結果、可視光を用いたDNA内光電荷分離に成功し、また、電荷分離収率および電荷分離寿命をDNA配列により制御可能であることを明らかにした。
Nanoscience of Photofuctionalized DNA
Grant number：17105005 2005 - 2009
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (S)
MAJIMA Tetsuro, FUJITSUKA Mamoru, KAWAI Kiyohiko, ENDO Masayuki
Grant amount：\107120000 （ Direct Cost: \82400000 、 Indirect Cost：\24720000 ）
Photoinduced charge separation and transfer mechanisms in DNA were clarified by using photofuctionalized DNA modified with various chromophores and high efficient and long-lifetime charge separation was established. Development of photoelectric energy conversion devices such as DNA molecular wire and light energy conversion units and highly effective DNA damage methods and creation of DNA photo-nanoscience was tried.
DNA自己組織化に基づくカーボンナノチューブアレイの構築
Grant number：17655085 2005 - 2006
日本学術振興会 科学研究費助成事業 萌芽研究
真嶋 哲朗, 川井 清彦
Grant amount：\3400000 （ Direct Cost: \3400000 ）
アレイ化したカーボンナノチューブを可視化することを目的とし、全反射蛍光顕微鏡を用いた単一分子蛍光顕微分光システムの構築を行った。具体的には、分光器および高感度CCDカメラを備え付けた全反射蛍光顕微鏡を開発した。本顕微分光システムの性能を評価するため、以下の研究を行った。二酸化チタン光触媒反応によって生成した一重項酸素などの酸素活性種を蛍光プローブにより単一分子レベルで検出することに成功した。二酸化チタン反応によって生成した一重項酸素は空気中へ飛散し、2mm以上離れた距離まで到達することを明らかにした。また、ペリレンナノ結晶の初期成長過程を水溶液中でその場観察することに成功し、種結晶形成機構に関する知見を得た。以上の結果から、本顕微分光システムが、単一ナノ材料の光誘起反応ならびに動的挙動の検出において強力な手法であることが明らかとなった。また、カーボンナノチューブと複合化させる自己組織化DNAにおける電荷移動機構を明らかにするため、レーザーフラッシュフォトリシス法による検討を行った。任意の塩基配列群をビルディングブロックとして用いることによりDNA中の電荷移動ダイナミクスを制御することに成功した。単層および多層カーボンナノチューブに蛍光色素を化学的に修飾し、カーボンナノチューブアレイの単一アレイ蛍光検出を行った。個々の蛍光色素修飾カーボンナノチューブアレイからの蛍光を検出することにより、集合体のサイズ、色素修飾率、光退色速度などを単一アレイレベルで評価した。
2波長2レーザー照射による高効率DNA切断
Grant number：15750007 2003 - 2004
日本学術振興会 科学研究費助成事業 若手研究(B)
川井 清彦
Grant amount：\3600000 （ Direct Cost: \3600000 ）
皮膚ガン、胃ガンの治療法の一つとして、近年光線力学療法(PDT)が注目されている。高齢、心不全、他の病気の直後で外科療法が困難な患者に対して特に有効な治療法となりうる。PDTによる合併症等の報告例はほとんどないが、唯一日光過敏症が問題となつている。したがって、外用した光増感剤が代謝されるまでの数週間にわたり遮光が必要となる。そのため、出来る限り外用する増感剤の量を減らす事が望まれる。また、光源としては比較的高強度のパルスレーザーを必要とし、治療時間を要するため照射面積に制約をうけ、一定期間に治療しうる患者数も制限される。そこで、PDT普及のためにも少量の光増感剤を用いた高効率DNA切断法の開発が望まれる。本研究では、2波長2レーザー励起法を用いた高効率DNA切断法の開発を目指した。一般的に、DNA光増感一電子酸化反応の量子収率は極めて低い。それは主に、電子移動反応によりDNA中に生じたラジカルカチオンと増感剤ラジカルアニオンの間の電荷再結合に由来する。そこで、我々は二段階目に透過性の高い長波長のレーザーを用いてラジカルアニオンを励起し、電子を溶媒中に放出し、電荷再結合を妨げるととによる高効率DNA切断を検討した。昨年度、二段階目のレーザーを用いて、増感剤ラジカルアニオンから、溶媒へと電子放出が可能であるか検討した。その結果、溶媒へと電子を放出できること確認した。本年度は、実際に2波長2レーザー照射法がDNA損傷効率に与える影響について調べた。その結果、一段階目のレーザーのみ、二段階目のレーザーのみを用いた場合と比較し、2波長2レーザー照射により最大で10倍以上の損傷の増加が観測され、2波長2レーザー照射の原理をPDTへと応用可能であることが示された。
Fundamental Science and Technology of Photofunctional Interfaces
Grant number：14050055 2001 - 2006
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research on Priority Areas
MAJIMA Tetsuro, TOJO Sachiko
Grant amount：\83800000 （ Direct Cost: \83800000 ）
The dynamic behaviors of radicals and radical ions generated on the surface of TiO_2 photocatalyst and the reactive intermediates from the reactions of the radicals and radical ions has been studied to elucidate 1) the reactive oxygen species and organic reactive intermediates generated during the TiO_2 photocatalytic reactions and 2) reactivities of organic radical ions generated during TiO_2 photocatalytic reactions, and to develop the method for the measurement of charge separation on the surface of the TiO_2 photocatalyst. There is an application to the environmental cleanup (contaminant processing) and medical technology as application of the TiO_2 photocatalyst reaction. An important finding was especially obtained in relation to it for the decomposition mechansm of the organic compounds in the TiO_2 photocatalyst reaction. In 2001-2005 fiscal years, we studied that adsorption and one-electron oxidation reaction process of the substrate adsorbed on the TiO_2 surface based on the time-resolved transient reflection measurement, and found that one-election oxidation efficiency depends on not only the oxidation potential of the substrate but also the electronic interaction between the substrate and surface of TiO_2 remarkably. In 2005-2007 fiscal years, we studied visible-light responsible TiO_2 photocatalyst, TiO_2 photocatalytic reaction in gas phase, one-electron redox processes during the polyoxometalate-mediated TiO_2 photocatalytic reactions, one-electron oxidation of organic molecule included in the cavity of β-cyclodextrin modified TiO_2 photocatalyst, and non-contact TiO_2 photocatalytic reaction based on the transient absorption measurement and single molecule fluorescence imaging technique. We found that the hydroxy radical and the singlet oxygen were generated from the surface of TiO_2 by the light irradiation of the TiO_2 photocatalyst and diffuse in 120 micrometer and 2 millimeter, respectively, in the atmosphere. We also studied nanoscopic heterogeneities in ddsorption and electron transfer processes of perylene diimide dye on TiO_2 nanoparticles, real-time single-molecule imaging of the spatial and temporal distribution of reactive oxygen species, and photocatalytic cleavage of single TiO_2/DNA nanoconjugates, as relation to solar cell, TiO_2 photocatalytic reaction mechanism at single molecule level, and DNA conjugate of TiO_2 photocatalyst.. In conclusion, our results can initiate to develop new TiO_2 photocatalyst and and the TiO_2 photocatalyst reaction system with a greatly highly efficiency and high selectivities.
Molecular devices by functionalization of modified DNA
Grant number：13305058 2001 - 2004
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
MAJIMA Tetsuro, FUJITSUKA Mamoru, TOJO Sachiko, KAWAI Kiyohiko, ENDO Masayuki
Grant amount：\55510000 （ Direct Cost: \42700000 、 Indirect Cost：\12810000 ）
In this research, it is aimed that various functionalities are given to modification DNA by using DNA modified covalently with various functional chromophores, controlling the functionalities can be established, and the possibility of modified DNA as molecular devices in the living body system is clarified. Especially, in order to clarify the hole transfer in DNA with respect to the construction of DNA molecular wire, photofunctions of modified DNA having photofunctional chromophores has been studied in the nano meter scale depending on the nuclear base sequences. Not only one chromophore but also several chromophores are modified on one DNA in order to clarify the charge separation, hole migration, and charge recombinataion in the nano meter scale and in the nano-pico second time scale. Technology that accurately operates functional molecule by means of molecular assembly is necessary to the nanotechnology of a bottom-up type, and it is necessary to establish the method of molecular assembly according to artificial information. DNA is the most powerful molecule where an accurate molecular assembly is achieved with many kinds of molecules and has the advantage that a variety of functional molecules can be introduced by the chemical modification in DNA. Therefore, DNA unit with the branch dividing structure was synthesized to construct a regular and rigid DNA structures based on self-assembly, and we succeeded to construct DNA nano structure to use this constructing a bridge DNA. In order to establish molecular devices by functionalization of modified DNA more precisely, to achieve the multifunction like the chlorophyll, photofunction, and complex functions is very important. It is also necessary to clarify the method of construction of modified DNA with a high performance and molecular device as a biomolecular function, and to develop the possibility of modified DNA as molecular devices in the living body system.
核酸の一電子移動、ホール移動に与える塩基対形成の影響の解明
Grant number：12750732 2000 - 2001
日本学術振興会 科学研究費助成事業 奨励研究(A)
川井 清彦
Grant amount：\2500000 （ Direct Cost: \2500000 ）
DNAの一電子酸化ではグアニンGのラジカルカチオンが生成し、鎖切断や変異が起こる。DNAの光電子移動反応を制御することが可能になれば、DNAの位置特異的切断によるガン治療などへの応用が可能になる。このような電子移動反応の制御として、水素結合による、方法が考えられる。そこで、核酸の-電子移動、ホール移動に与える塩基対形成の影響の解明を目的に1)核酸塩基対が一電子酸化反応速度に与える影響の解明、2)塩基対の形成がホール移動速度、反応性、反応生成物に与える影響の解明、3)核酸塩基対の形成が変異原生成物に与える影響の解明について研究を行い特に核酸塩基対の形成がDNAの一電子酸化反応速度に与える影響を明らかにするとともに、水素結合によって核酸塩基の一電子酸化反応速度を制御できることを見出した。ところで、DNAでは隣り合う核酸塩基どうしのπ-スタッキングとともにG : CおよびA : T核酸塩基対間の水素結合が存在する。それぞれが電子移動反応に対してどのような効果を示すのかはわかっていない。そのためには、実験的に2つの効果を分離した系を構築するこたが必要になる。我々はDNAの光電子移動反応におよぼす水素結合の効果を明らかにするため、DNAの親水的環境を模したジクロロエタン中のG : C塩基対の光電子移動反応によるグアニンの一電子酸化反応をナノ秒レーザーフラッシュホトリシス法によって検討した。さらに、C上の置換基の電子的性質によってグアニンの光電子移動反応速度を制御できることを見出した。結論として、電子移動反応の水素結合による制御は、緑色植物光合成系IIなどの電子移動系で重要であるようにDNAの一電子酸化においても重要な役割を果たしていることがわかった。
数珠玉状および網目状フラーレン連結分子の光化学反応による生成
Grant number：11875187 1999 - 2000
日本学術振興会 科学研究費助成事業 萌芽的研究
真嶋 哲朗, 佐治 幸子, 一ノ瀬 暢之, 石田 昭人, 川井 清彦
Grant amount：\2300000 （ Direct Cost: \2300000 ）
本研究では、有機分子の光化学反応によってビラジカルを発生させ、「ラジカルスポンジ」としてのC_<60>フラーレンに付加反応することを利用して、数珠玉状および網目状フラーレン連結分子の生成について検討した。有機光化学反応によるビラジカル発生法として、種々のシクロアルカンの環のC-C結合開裂、シクロアルカノンのアシル基のα開裂によって、アルカンのメチレン鎖を変化させることによる1,n-ビラジカルの発生、カルボニル基の分子内γ水素引き抜きによる1,4-ビラジカルの発生を、溶液中のレーザーフラッシュホトリシス法(励起レーザーとして主にXeClエキシマーレーザー308nm光を使用)によるビラジカルの過渡吸収測定から検討した。この結果、様々な原料を使用した光化学反応によって様々なビラジカルを発生させることができ、原料の有機分子の吸収にあった波長の高強度のレーザー光を照射することによって光化学反応を効率的に起こし、高密度・高濃度のビラジカルを発生させることが可能であることがわかった。次に、溶液中にC_<60>フラーレンを共存させておき、前述のXeClエキシマーレーザー励起による有機光化学反応によってビラジカルを発生させ、ビラジカルとC_<60>フラーレンとの付加反応を検討した。これら混合系では、ビラジカルの過渡吸収がC_<60>フラーレン基底状態の吸収と重なっているため、ビラジカルの過渡吸収測定は困難であった。また、C_<60>フラーレン自身もXeClエキシマーレーザー照射によって励起される。しかし、両者の濃度調整によって有機化合物の光化学反応を優先的に起こし、ビラジカルを発生させることができる場合を見い出した。実際に生成した炭素成分の質量測定によれば、数珠玉状および網目状フラーレン連結分子が生成している可能性が示唆された。
ラジカルイオンにおけるスピン-電荷の非局在化
Grant number：11133236 1999
日本学術振興会 科学研究費助成事業 特定領域研究(A)
真嶋 哲郎, 佐治 幸子, 一ノ瀬 暢之, 石田 昭人, 川井 清彦
Grant amount：\2000000 （ Direct Cost: \2000000 ）
本研究では、分子内スピン電荷混成場においてスピンと電荷とをそれぞれ原子レベルで位置選択的に局在化または非局在化、分離または接近させることによって、スピン場と電荷場との非局在電子系としての性質どのように変化するかを検討し、非局在電子系としての特徴を明らかにする。特に、スピン-正電荷の非局在化という観点からラジカルカチオンの光励起状態の発光について検討した。多くの芳香族化合物の励起一重項状態は発光性であり、それらはベンゼン環の平面性が高く、π電子の非局在化が一因となっている。電子線パルス/パルスレーザー2段階励起蛍光法(電子線パルスラジオリシス-レーザーフラッシュホトリシス法)を用いて、種々の芳香族化合物(M=ベンゼン、ナフタレン、メチルナフタレン、アントラセン、フェノール、トルエン、キシレン、メシチレン、ヘキサメチルベンゼン、アニソール、1,4ジメトキシベンゼン、1,3,5-トリメトキシベンゼン(TMB)など約50種類)のアルゴン飽和ベンゾニトリル(BN)溶液の電子線パルスラジオリシスによりそれぞれラジカルカチオン(M^<・+>)を発生させ、続いてM^<・+>の寿命内にM^<・+>の吸収にあったNd:YAGレーザーの高調波(535または355nm)を照射してM^<・+>の光励起状態を発生させ、その蛍光を観測する2段階励起蛍光法を用いて、M^<・+>の蛍光を測定した。これらの内、TMB^<・+>の蛍光が観測された(量子収率値1.1×10^<-3>)。ベンゼンのメトキシ置換体の内、TMB^<・+>のみが蛍光性を示すことを見出した。3,5-ジメトキシフェノールおよび1,3,5-トリフェノールのラジカルカチオンも蛍光を示し、量子収率は2×10^<-3>であった。結果として、M^<・+>の発光に対してM^<・+>の分子軌道のエネルギーと構造が重要であること、これはスピン-正電荷の非局在にも関係することがわかった。
Studies on the Multi-responsible Molecular Systems Involving Visible Light Switching Using Radical Ions
Grant number：09450319 1997 - 1999
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
MAJIMA Tetsuro, SAJI Sachiko, ICHINOSE Nobuyuki, ISHIDA Akito, KAWAI Kiyohiko
Grant amount：\3100000 （ Direct Cost: \3100000 ）
Radical ions have sharp and intense absorption bands in the visible wavelength range which depend on the structure and substituents of the radical ions. Therefore, it is suggested that radical ions can be excited by diode lasers, that undestructed reading of memory can be essentially performed with high sensitivity, and that triple memory of a molecule can be done with three independent characters of the neutral molecule and radical cation and anion of the molecule. Radical ions are used as starting material for developing of a new multiple-photoresponsible molecular system on the basis of their visile light switching characters. Since radical ions are well known to be generated from radiation reactions and are stable in the μs time scale in solution at room temperature, this study was carried out with a pulse radiolysis-laser flash photolysis combined method which is constructed at ISIR, Osaka University. Photoresponsiblity was examined through one-way photoisomerization of cis-stilbene radical cation to trans-stilbene radical cation, intermolecular electron transfer from pyrene radical anion in the photoexcited state to an electron acceptor such as bipheny1, and multiple-isomerizations of 1, 4-dipheny1-1, 3-butadiene radical cation and 1, 6-dipheny1-1, 3, 5-hexatriene radical cation. On the basis of experimental results, a new idea of multiple memory involving a neutral mlecule and the radical ions is proposed and possibility of photon-mode memory with high density is suggested by reversible reactions of radical ions. Since photoresponsible reactions of radical ions are performed in an appropriate time range after irradiation of an electron pulse, they are established to be electron-pulse gated photoresponsible reactions. Moreover, various types of molecules are synthesized to be suitable for the multi-responsible molecular systems involving visible light switching using radical ions. Radical ions of the synthetic molecular systems were used to develop new photoresponsible functional materials with high reliability and high speed from visible light as the information source.
Laser Flash Photolysis and Pulse Radiolysis
Grant type：Competitive
Chemistry of Radical Ions
Grant type：Competitive
Chemistry of Nucleic Acid
Grant type：Competitive
化学概論
Institution：大阪大学
超分子ナノバイオプロセス学
Institution：大阪大学
励起分子化学
Institution：大阪大学
やさしい科学技術セミナー
Role(s)： Appearance, Presenter, Planner, Demonstrator
国際科学技術財団・大阪大学 「光で生命を見る～研究はきらきらした芸術！～」 2012.10
