We study the degradation and synthesis of the wood components cellulose, hemicellulose, and lignin, mainly using enzymes from wood-rotting fungi. Cellulose, for example, is a polysaccharide that makes up about 50% of plant cell walls and is the most abundant biomass on earth. Although wood-rotting fungi use a variety of enzymes to break down cellulose and utilize it as a source of nutrients, there are still many unknowns regarding the mechanisms by which they do so. By clarifying the process of cellulose degradation in nature, we hope to pick up ideas for extracting energy from cellulosic biomass or converting it into useful materials, and to help build a recycling-oriented society.
April 1990 – March 1994: Faculty of Agriculture, the University of Tokyo
April 1994 – March 1996: M.A., Graduate School of Agriculture and Life Sciences, the University of Tokyo
April 1996 – March 1999: Ph.D., Graduate School of Agricultural and Life Sciences, the University of Tokyo
April 1998 – March 1999: DC, JSPS Research Fellowship for Young Scientists
April 1999 – March 2002: PD, JSPS Research Fellowship for Young Scientists
September 2000 – August 2001: Doctoral Researcher, Uppsala University, Sweden
April 2002 – March 2007: Assistant, Graduate School of Agricultural and Life Sciences, the University of Tokyo
April 2007 – March 2009: Assistant Professor, Graduate School of Agricultural and Life Sciences, the University of Tokyo
April 2009 – March 2021: Associate Professor, Graduate School of Agricultural and Life Sciences, the University of Tokyo
July 2011 – June 2014: National Personnel Authority (NPA), Examination Board Committee National Personnel Authority, Permanent Government Employees Examination
April 2014 – March 2016: Member of the Committee (Biology), National Center for University Entrance Examinations
January 2016 – December 2019: Visiting Professor, VTT Technical Research Centre of Finland Ltd
August 2017 – July 2019: Senior Scientific Research Specialist, Scientific Research Aid Division, Research Promotion Bureau, Ministry of Education, Culture, Sports, Science and Technology, Japan
April 2018 – Present: Fellow, Technology Strategy Center (TSC), New Energy and Industrial Technology Development Organization (NEDO)
April 2021 – Present: Professor, Graduate School of Agricultural and Life Sciences, the University of Tokyo
Uchiyama, T., Uchihashi, T., Ishida, T., Nakamura, A., Vermaas, J. V., Crowley, M. F., Samejima, M., Beckham, G. T., and Igarashi, K., Lytic polysaccharide monooxygenase increases cellobiohydrolases activity by promoting decrystallization of cellulose surface, Science Adv. 8 (51): eade5155 (2022) https://www.science.org/doi/10.1126/sciadv.ade5155
Kojima, K., Sunagawa, N., Mikkelsen, N. E., Hansson, H., Karkehabadi, S., Samejima, M., Sandgren, M., and Igarashi, K., Comparison of glycoside hydrolase family 3 β-xylosidases from basidiomycetes and ascomycetes reveals evolutionarily distinct xylan degradation systems. J. Biol. Chem. 298 (3), 101670 (2022) https://doi.org/10.1016/j.jbc.2022.101670
Matsuyama, K., Kishine, N., Fujimoto, Z., Sunagawa, N., Kotake, T., Tsumuraya, Y., Samejima, M., Igarashi, K., and Kaneko S., Unique active site and subsite features in the arabinogalactan-degrading GH43 exo-β-1,3-galactanase from Phanerochaete chrysosporium, J. Biol. Chem. 295 (52): 18539-18552 (2020) https://doi.org/10.1074/jbc.RA120.016149
Uchiyama, T., Uchihashi, T., Nakamura, A., Watanabe, H., Kaneko, S., Samejima, M., and Igarashi K., Convergent evolution of processivity in bacterial and fungal cellulases, Proc. Nat. Acad. Sci. U.S.A. 117 (33) 19896-19903 (2020) https://doi.org/10.1073/pnas.2011366117
Ezaki, T., Nishinari, K., Samejima, M., and Igarashi, K., Bridging the micro-macro gap between single-molecular behavior and bulk hydrolysis properties of cellulase, Phys. Rev. Lett. 122, 9, 5 p., 098102 (2019) http://dx.doi.org/10.1103/PhysRevLett.122.098102
Nakamura, A., Ishida, T., Kusaka, K., Yamada, T., Fushinobu, S., Tanaka, I., Kaneko, S., Ohta, K., Tanaka, H., Inaka, K., Higuchi, Y., Niimura, N., Samejima, M., and Igarashi, K., “Newton’s cradle” proton relay with amide-imidic acid tautomerization in inverting cellulase visualized by neutron crystallography, Science Adv. 1: e1500263 (2015) https://doi.org/10.1126/sciadv.1500263
Igarashi, K., Uchihashi, T., Uchiyama, T., Sugimoto, H., Wada, M., Suzuki, K., Sakuda, S., Ando, T., Watanabe, T., and Samejima, M., Two-way traffic of glycoside hydrolase family 18 processive chitinases on crystalline chitin, Nature Commun. 5: 3975 (2014) https://doi.org/10.1038/ncomms4975
Nakamura, A., Watanabe, H., Ishida, T., Uchihashi, T., Wada, M., Ando, T., Igarashi, K., and Samejima, M., Trade-off between processivity and hydrolytic velocity of cellobiohydrolases at the surface of crystalline cellulose, J. Amer. Chem. Soc. 136: 4584–4592 (2014) https://doi.org/10.1021/ja4119994
Igarashi, K., Cooperative biomass breakdown, Nature Chem. Biol. 9: 350-351 (2013) https://doi.org/10.1038/nchembio.1237
Igarashi, K., Uchihashi, T., Koivula, A., Wada, M., Kimura, S., Okamoto, T., Penttilä, M., Ando, T., and Samejima, M., Traffic jams reduce hydrolytic efficiency of cellulase on cellulose surface, Science 333: 1279-1282 (2011) https://doi.org/10.1126/science.1208386
Igarashi, K., Koivula, A., Wada, M., Kimura, S., Penttila, M., and Samejima, M., High-speed atomic force microscopy visualizes processive movement of Trichoderma reesei cellobiohydrolase I on crystalline cellulose, J. Biol. Chem. 284:36186-36190 (2009) https://doi.org/10.1074/jbc.m109.034611
Japan Applied Glycoscience Society Award 2023: “Analysis of the Reaction Mechanism in Hydrolytic and Redox Enzymes Related to Cellulose Biodegradation”
The Japan Wood Research Society Prize 2022: “Structural-Functional Correlation in Enzymes Involved in Plant Cell Wall Polysaccharide Degradation” (January 29, 2022)
12th JSPS Prize 2016 (Japan Society for the Promotion of Science) : “Elucidation of Molecular Mechanisms in Enzymatic Decomposition of Cellulosic Biomass” (February 24, 2016)
Guinness World Records™: “Highest Resolution X-ray Crystallography Image of an Enzyme” (certified on January 27, 2016)
Ichimura Academic Award 2014 (Contribution Prize): “Alleviating Enzyme Traffic Jams for the Realization of Biorefineries” (April 23, 2015)
The Cellulose Society of Japan Award 2012: “Elucidation of Enzymatic Mechanisms in Crystalline Cellulose Degradation Using Single-Molecule Visualization Techniques” (July 18, 2013)
