Nucleotide-dependent conformational changes in a protease-associated ATPase HsIU

Citation
J. Wang et al., Nucleotide-dependent conformational changes in a protease-associated ATPase HsIU, STRUCTURE, 9(11), 2001, pp. 1107-1116
Citations number
57
Categorie Soggetti
Biochemistry & Biophysics
Journal title
STRUCTURE
ISSN journal
09692126 → ACNP
Volume
9
Issue
11
Year of publication
2001
Pages
1107 - 1116
Database
ISI
SICI code
0969-2126(200111)9:11<1107:NCCIAP>2.0.ZU;2-I
Abstract
Background: The bacterial heat shock locus ATPase HslU is an AAA(+) protein that has structures known in many nucleotide-free and -bound states. Nucle otide is required for the formation of the biologically active HslU hexamer ic assembly. The hexameric HslU ATPase binds the dodecameric HsIV peptidase and forms an ATP-dependent HsIVU protease. Results: We have characterized four distinct HsIU conformational states, go ing sequentially from open to closed: the empty, SO4, 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 nucleot ide identity in one structure and reveals the ATP hydrolysis-dependent stru ctural changes in the HsIVU complex, including a ring rotation and a confor mational change of the HslU C terminus. This leads to an amended protein un folding-coupled translocation mechanism. Conclusions: The observed nucleotide-dependent conformational changes in Hs lU and their governing principles provide a framework for the mechanistic u nderstanding of other AAA(+) proteins.