Biostructural Mechanism Laboratory

There are many huge macromolecular complexes in living organisms. They are often hard to crystallize because of their size, complexity and heterogeneity. Cryo-electron microscopy is a suitable method to analyze the structures of such biological macromolecules, because it can be applied to various forms of samples, e.g. two-dimensional crystal, helical assembly, spherical virus, dispersed particle, cell organelle and cell, although attainable resolution depends on the system. We are studying the working mechanisms of such macromolecular complexes by cryo-electron microscopy, and also developing new techniques to achieve higher resolutions. X-ray crystallography and coherent X-ray imaging are also applied for this purpose. Targets include the bacterial flagellar motor, energizing membrane proteins and DNA and its binding protein complexes.

Research Subjects

• Electron crystallogarphy of biological macromolecules
• Structure analysis of membrane protein
• Development of structure analysis of biological molecules
• Analysis of telomere structures

Publications

1. Yonekura, K., Maki-Yonekura, S. and Homma, M.:
   "Structure of the Flagellar Motor Protein Complex PomAB: Implications for the Torque-Generating Conformation."
   J. Bacteriol. (2011) 193: 3863-3870
2. Maki-Yonekura S., Yonekura K. and Namba K.:
   "Conformational change of flagellin for polymorphic supercoiling of the flagellar filament."
   Nat. Struct. Mol. Biol. (2010) 17: 417-422
3. Williams T. L., Levy D. L.., Maki-Yonekura S., Yonekura K. and Blackburn E. H.:
   "Characterization of the yeast telomere nucleoprotein core: Rap1 binds independently to each recognition site."
   J. Biol. Chem. (2010) 285: 35814-35824
4. Maki-Yonekura S. and Yonekura K.:
   "Electron digital imaging towards high-resolution structure analysis of biological macromolecules"
   Microsc. Microanal. (2008) 14: 362-369
5. Yonekura K., Braunfeld M. B., Maki-Yonekura S. and Agard D. A.:
   "Electron energy filtering significantly improves amplitude contrast of frozen-hydrated protein at 300 kV"
   J. Struct. Biol. (2006) 156: 524-536
6. Yonekura K., Yakushi T., Atsumi T., Maki-Yonekura S., Homma M. and Namba K.:
   "Electron cryomicroscopic visualization of PomA/B stator units of the sodium-driven flagellar motor in liposomes"
   J. Mol. Biol. (2006) 357: 73-81
7. Yonekura K., Maki-Yonekura S. and Namba K.:
   "Building the atomic model for the bacterial flagellar filament by electron cryomicroscopy and image analysis"
   Structure (2005) 13: 407-412
8. Maki-Yonekura S., Yonekura K. and Namba K.:
   "Domain movements of HAP2 in the cap-filament complex formation and growth process of the bacterial flagellum"
   Proc. Natl. Acad. Sci. USA (2003) 100: 15528-15533
9. Yonekura K., Maki-Yonekura S. and Namba K.:
   "Complete atomic model of the bacterial flagellar filament by electron cryomicroscopy"
   Nature (2003) 424: 623-650
10. Yonekura K., Maki-Yonekura S. and Namba K.:
    "Quantitative comparison of zero-loss and conventional electron diffraction from 2D and thin 3D protein crystals"
    Biophys. J. (2002) 82:2784-2797