Structural studies on Helicobacter pyloriATP-dependent protease, FtsH
Sung Hyun Kim1, Gil Bu Kang, Hye Eun Song
1Department of Life Science, Cell Dynamics Research Center, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea.
Abstract:
The ATP-dependent protease, FtsH, degrades misassembled membrane proteins for quality control like SecY, subunit a of FoF1-ATPase, and YccA, and digests short-lived soluble proteins in order to control their cellular regulation, including sigma32, LpxC and lambdacII. The FtsH protein has an N-terminal transmembrane segment and a large cytosolic region that consists of two domains, an ATPase and a protease domain. To provide a structural basis for the nucleotide-dependent domain motions and a better understanding of substrate translocation, the crystal structures of the Helicobacter pylori (Hp) FtsH ATPase domain in the nucleotide-free state and complexed with ADP, were determined. Two different structures of HpFtsH ATPase were observed, with the nucleotide-free state in an asymmetric unit, and these structures reveal the new forms and show other conformational differences between the nucleotide-free and ADP-bound state compared with previous structures. In particular, one HpFtsH Apo structure has a considerable rotation difference compared with the HpFtsH ADP complex, and this large conformational change reveals that FtsH may have the mechanical force needed for substrate translocation.
Insights
The ATP-dependent protease FtsH
Area of Science:
- Biochemistry
- Molecular Biology
- Structural Biology
Background:
- FtsH is an ATP-dependent protease crucial for cellular quality control.
- It degrades misfolded membrane proteins and regulates short-lived soluble proteins.
- FtsH possesses an N-terminal transmembrane segment and cytosolic ATPase and protease domains.
Purpose of the Study:
- To elucidate the structural basis of nucleotide-dependent domain motions in FtsH.
- To understand the mechanism of substrate translocation by FtsH.
- To determine the crystal structures of the Helicobacter pylori FtsH ATPase domain.
Main Methods:
- X-ray crystallography was used to determine the structures.
- Structures were obtained for the nucleotide-free (Apo) state and ADP-bound complex.
- Conformational differences between nucleotide-free and ADP-bound states were analyzed.
Main Results:
- Two distinct structures of the HpFtsH ATPase domain were observed.
- Significant conformational differences were identified between the Apo and ADP-bound states.
- One Apo structure exhibited a substantial rotation compared to the ADP complex.
Conclusions:
- The observed large conformational change suggests FtsH possesses mechanical force for substrate translocation.
- Structural insights into nucleotide-dependent domain movements were provided.
- This study enhances the understanding of FtsH function in protein quality control and regulation.
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