Division of Structural Biology


Structural biology by cryo-electron microscopy

Living organisms are formed by biomolecules like proteins and are maintained by their chemical reactions. In our laboratory, we are studying the structures of these biomolecules using cryo-electron microscopy (cryo-EM) to elucidate these molecular mechanisms.
  Cryo-EM is a method for directly observing a biological sample with an electron microscope by rapidly freezing and keeping it at a low temperature. This makes it possible to analyze the structure of biomolecules that are close to the living state at the atomic level.
The main research instruments are a 300kV Cold-FEG cryo-EM with the original bottom mount energy filter (TITAN Krios G4), a 200 kV cryo-EM equipped with an electron direct detection camera and in-column energy filter (JEM2200FS), and a cryo-FIB SEM (Aquilos2)(Fig. 1). The 3D structures of biomolecules are then reconstructed by single particle analysis or electron tomography (ET) with GP-GPU computers.
Figure 2 shows the six structural states of enterococcus V type ATPase revealed by cryo-electron microscopy single particle analysis (Burton-Smith et al. 2023). This result clarified the relationship between the function and structure of this rotary sodium pump.
We welcome young researchers and graduate students who are interested in such structural biology research.

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Fig. 1 
300kV cryo-EM, TITAN Krios G4 (right), 200kV cryo-EM, JEM2200FS (middle), and cryo-FIB SEM (right).



Fig. 2
2 Six structural states of Enterococcus V type ATPase. Continuous ATP hydrolysis in the V1 domain (left) causes the central rotor to rotate, and this rotation is transmitted to the Vo domain in the membrane (left), causing sodium ions to be expelled from the cell.


Selected publications

*Burton-Smith et al., Comm Biol 6, 755 (2023)
*Okamoto et al., J Gen Virol 104(6) (2023)
*Fukuda et al., Mol Cell 83(12), 2045-2058.e9 (2023)
*Ishii et al., Elife 12, e84488 (2023)