Nucleotide-Dependent Conformational Changes in a Protease-Associated ATPase HslU

File:1hqy.gif


1hqy, resolution 2.80Å

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OverviewOverview

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.

About this StructureAbout this Structure

1HQY is a Protein complex structure of sequences from Escherichia coli with as ligand. Full crystallographic information is available from OCA.

ReferenceReference

Nucleotide-dependent conformational changes in a protease-associated ATPase HsIU., Wang J, Song JJ, Seong IS, Franklin MC, Kamtekar S, Eom SH, Chung CH, Structure. 2001 Nov;9(11):1107-16. PMID:11709174

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