1HT2: Nucleotide-Dependent Conformational Changes in a Protease-Associated ATPase HslU

BACKGROUND: The bacterial heat shock locus ATPase HslU is an AAA(+) protein that has structures known in many nucleotide-free and -bound states. Nucleotide is required for the formation of the biologically active HslU hexameric assembly. The hexameric HslU ATPase binds the dodecameric HslV peptidase and forms an ATP-dependent HslVU protease. RESULTS: We have characterized four distinct HslU conformational states, going sequentially from open to closed: the empty, SO(4), ATP, and ADP states. The nucleotide binds at a cleft formed by an alpha/beta domain and an alpha-helical domain in HslU. The four HslU states differ by a rotation of the alpha-helical domain. This classification leads to a correction of nucleotide identity in one structure and reveals the ATP hydrolysis-dependent structural changes in the HslVU complex, including a ring rotation and a conformational change of the HslU C terminus. This leads to an amended protein unfolding-coupled translocation mechanism. CONCLUSIONS: The observed nucleotide-dependent conformational changes in HslU and their governing principles provide a framework for the mechanistic understanding of other AAA(+) proteins.
PDB ID: 1HT2Download
MMDB ID: 17885
PDB Deposition Date: 2000/12/27
Updated in MMDB: 2001/12
Experimental Method:
x-ray diffraction
Resolution: 2.8  Å
Source Organism:
Similar Structures:
Biological Unit for 1HT2: tetradecameric; determined by author
Molecular Components in 1HT2
Label Count Molecule
Proteins (14 molecules)
Heat Shock Locus Hslv(Gene symbol: hslV)
Molecule annotation
Heat Shock Locus Hslu(Gene symbol: hslU)
Molecule annotation
Chemicals (6 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB