Molecular mechanism of the bacterial flagellar axial coupling joint
Grant-in-Aid for Scientific Research (B)
|Allocation Type||Single-year Grants |
|Research Institution||Osaka University |
IMADA Katsumi Osaka University, Department of Frontier Biosciences, Associate Professor, 大学院生命機能研究科, 助教授 (40346143)
NAMBA Keiichi Osaka University, Department of Frontier Biosciences, Professor, 大学院生命機能研究科, 教授 (30346142)
|Project Period (FY)
2004 – 2006
Completed (Fiscal Year 2006)
|Budget Amount *help
¥10,300,000 (Direct Cost: ¥10,300,000)
Fiscal Year 2006: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 2005: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 2004: ¥6,800,000 (Direct Cost: ¥6,800,000)
|Keywords||Structural Biology / Electron microscopy / Nano-Biology / Nano-Machine / X-ray crystallography / 分子モーター / 1分子計測(SMD)|
1.X-ray crystallographic studies of the flagellar axial proteins and their complexes
(1) Crystal structure of a 26 kDa fragment of HAP3 was solved at 1.9 Å resolution (PDB ID:2D4X).
(2) Crystal structure of a 49 kDa fragment of HAP1 was solved at 2.1 Å resolution (PDB ID:2D4Y).
(3) We found a stable complex of HAP2-HAP3-FlgN and established a purification procedure of the complex.
(4) We obtained small crystals of the HAP1-FlgN complex.
2. Analyses of the flagellar axial structure from the hook to the filament.
(1) Structure of the hook
An atomic model of the hook was constructed by fitting the X-ray structure of a 31 kDa fragment of FlgE into the density map obtained from electron cryo-microscopy. The model and following simulation studies revealed the molecular universal joint mechanism.
(2) Structure of the hook-filament junction
We built the partial structural model of the hook-filament junction, based on the crystal structures of HAP1 and HAP3, the filament and the hook model. The structure clearly indicated the molecular mechanism of how to couple the mechanically distinct two structures and to transmit torque smoothly.
(3) Molecular dynamics simulation of the axial structure
Two different types of molecular dynamics simulation studies were conducted on the flagellar filament model. Switch interactions which control the energy frustration and polymorphic transition were identified from a massive MD simulation. Solvent effects on the'polymorphic transition were demonstrated from the coarse-grained MD simulations.
3.Structure analysis of the rod and the rod-hook complex
(1) We have reconstructed the distal rod from the hook using purified FlgG proteins and the short hook fragments.
(2) We purified the basal body from a poly rod mutant strain and analyzed the structure of the poly rod at 8.1 Å resolution by electron cryo-microscopy.
Report (4 results)
Research Products (26 results)