Centers & Labs

RIKEN Quantitative Biology Center

Office for Supramolecular System Dynamics Research Collaboration

Head: Keiichi Nanba (D.Eng.)
Keiichi  Nanba(D.Eng.)

To gain deep understanding of the mechanisms of biomolecular motor protein assemblies, such as bacterial flagella and muscle filaments, we make combined use of electron cryomicroscopy and image analysis with X-ray diffraction and optical nanophotometry as well as genetic engineering and protein biochemistry to visualize their three-dimensional structures and dynamics at high-temporal and spatial resolutoin. We also develop advanced technologies of electron cryomicroscopy and image analysis as well as optical nanophotometry on our own.

Research Subjects

  • Structures and functions of molecular motor assemblies such as bacterial flagella and muscle filaments
  • Development in electro cryomicroscopy and image analysis for high-resolution, high-throughput structural analysis

Selected Publications

  1. Saijo-Hamano, Y., Matsunami, H., Namba, K. and Imada, K.:
    "Expression, purification, crystallization and preliminary X-ray diffraction analysis of a core fragment of FlgG, a bacterial flagellar rod protein."
    Acta Cryst., F69, 547-550, 2013
  2. Moriya, N., Minamino, T., Ferris, U.H., Morimoto, V.Y., Ashihara, M., Kato, T. and Namba, K.:
    "Role of the Dc domain of the bacterial hook protein FlgE in hook assembly and function."
    BIOPHYSICS 9, 63-72, 2013.
  3. Bai, F., Che, Y.-S., Kami-ike, N., Ma, Q., Minamino, T., Sowa, Y. & Namba, K.:
    "Populational heterogeneity vs. temporal fluctuation in Esherichia coli flagellar motor switching."
    Biophis. J., 105, 2123-2129, 2013.
  4. Stadler, A.M., Unruh, T., Namba, K., Samatey, F., Zaccai, G.:
    "Correlation between supercoiling and conformational motions of the bacterial flagellar filament."
    Biophysical Journal, 105, 2157-2165, 2013.
  5. Kinoshita, M., Hara, N., Imada, K., Namba, K. & Minamino, T.:
    "Interactions of bacterial flagellar chaperone-substrate complexes with FlhA contribute to coordinating assembly of the flagellar filament."
    Mol. Microbiol., 90, 1249-1261, 2013.
  6. Castillo, D.J., Nakamura, S., Morimoto, Y.V., Che, Y.-S., Kami-ike, N., Kudo, S., Minamino, T. & Namba, K.:
    "The C-terminal periplasmic domain of MotB is responsible for load-dependent control of the number of stators of the bacterial flagellar motor."
    BIOPHYSICS, 9, 173-181, 2013.
  7. Che, Y.-S., Nakamura, S., Morimoto, Y.V., Kami-ike, N., Namba, K. & Minamino, T.:
    "Load-sensitive coupling of proton translocation and torque generation in the bacterial flagellar motor."
    Mol. Microbiol., 91, 175-184, 2014.
  8. Kawamoto, A., Morimoto, Y.V., Miyata, T., Minamino, T., Hughes, K.T., Kato, T. & Namba, K.:
    "Common and distinct structural features of Salmonella injectisome and flagellar basal body."
    Scientific Reports, 3, 3369, 2013.
  9. Nakamura, S., Leshansky, A., Magariyama, Y., Namba, K. & Kudo, S.:
    "Direct measurement of helical cell motion of the spirochete Leptospira."
    Biophysical Journal, in press
  10. Morimoto, Y.V., Ito, M., Hiraoka, K.D., Che, Y-S., Bai, F., Kami-ike, N., Namba, K. & Minamino, T.:
    "Assembly and stoichiometry of FliF and FlhA in Salmonella flagellar basal body."
    Mol. Microbiol., in press