The N-terminal zinc binding domain of ClpX is a dimerization domain that modulates the chaperone function
Wojtyra, U. A.
Houry, Walid A.
Date of Issue2003
School of Biological Sciences
Clp ATPases are unique chaperones that promote protein unfolding and subsequent degradation by proteases. The mechanism by which this occurs is poorly understood. Here we demonstrate that the N-terminal domain of ClpX is a C4-type zinc binding domain (ZBD) involved in substrate recognition. ZBD forms a very stable dimer that is essential for promoting the degradation of some typical ClpXP substrates such as _O and MuA but not GFP-SsrA. Furthermore, experiments indicate that ZBD contains a primary binding site for the _O substrate and for the cofactor SspB. Removal of ZBD from the ClpX sequence renders the ATPase activity of ClpX largely insensitive to the presence of ClpP, substrates, or the SspB cofactor. All these results indicate that ZBD plays an important role in the ClpX mechanism of function and that ATP binding and/or hydrolysis drives a conformational change in ClpX involving ZBD.
Journal of Biological Chemistry
© 2003 by The American Society for Biochemistry and Molecular Biology, Inc. This paper was published in Journal of Biological Chemistry and is made available as an electronic reprint (preprint) with permission of ASBMB. The paper can be found at the following official DOI:[http://dx.doi.org/10.1074/jbc.M307825200]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.