Article
- The EMBO Journal (2006) 25, 3367 - 3376
- doi:10.1038/sj.emboj.7601223
Published online: 29 June 2006
Subject Categories:
Large nucleotide-dependent movement of the N-terminal domain of the ClpX chaperone
Guillaume Thibaulta, Yulia Tsitrina, Toni Davidson, Anna Gribun and Walid A Houry
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
Correspondence to:
Walid A Houry, Department of Biochemistry, University of Toronto, 1 King's College Circle, Medical Sciences Building, Toronto, Ontario, Canada M5S 1A8. Tel.: +1 416 946 7141; Fax: +1 416 978 8548; E-mail: walid.houry@utoronto.ca
aThese authors contributed equally to this work
Received 16 December 2005; Accepted 13 June 2006
Abstract
The ClpXP ATPase–protease complex is a major component of the protein quality control machinery in the cell. A ClpX subunit consists of an N-terminal zinc binding domain (ZBD) and a C-terminal AAA+ domain. ClpX oligomerizes into a hexamer with the AAA+ domains forming the base of the hexamer and the ZBDs extending out of the base. Here, we report that ClpX switches between a capture and a feeding conformation. ZBDs in ClpX undergo large nucleotide-dependent block movement towards ClpP and into the AAA+ ring. This motion is modulated by the ClpX cofactor, SspB. Evidence for this movement was initially obtained by the surprising observation that an N-terminal extension on ClpX is clipped by bound ClpP in functional ClpXP complexes. Protease-protection, crosslinking, and light scattering experiments further support these findings.
Keywords:
- ClpP,
- ClpX,
- nucleotide-dependent domain movement,
- translocation
