PROSITE documentation PDOC51902
ClpX zinc binding (ZB) domain profile


Molecular chaperones and proteases are part of an essential quality control machinery in the cell, which ensures the conformational integrity of proteins under conditions of normal growth as well as under stress. Prokaryotic and organellar ClpX is a molecular chaperone which can also work as a specificity factor for the ClpP protease. The chaperone ClpX associates with the serine protease ClpP to form ClpXP, a cylindrical structure that is similar to the 26S proteasome. ClpX binds and, subsequently, unfolds and translocates substrate proteins into the ClpP chamber in an ATP-dependent manner. ClpX consists of an NH(2)-terminal zinc binding (ZB) domain that is involved in substrate and cofactor recognition and a AAA(+) domain that arranges into a hexamer in an ATP-dependent manner. The ClpX ZB domain contains the characteristic pattern C-X(2)-C-X(18)-C-X(2)-C of four cysteine residues and forms a constitutive dimer that is essential for the degradation of some ClpX substrates such as lambdaO and MuA but is not required for the degradation of other substrates such as green fluorescent protein SsrA [1,2,3,4,5].

The core of the ClpX-type ZB domain is organized into two hairpins followed by one α-helix (see <PDB:1OVX>). Dimerization brings the sole α-helices from each monomer together in an anti-parallel orientation when viewed from one symmetry axis, and the second β-hairpins together along a second symmetry axis. The dimer interface consists of highly conserved hydrophobic residues. The four conserved cysteines are involved in the coordination of one Zn(II) ion per monomer [3,4,5].

The profile we developed covers the entire ClpX-type ZB domain.

Last update:

August 2019 / First entry.


Technical section

PROSITE method (with tools and information) covered by this documentation:

CLPX_ZB, PS51902; ClpX zinc binding (ZB) domain profile  (MATRIX)


1AuthorsCorydon T.J. Wilsbech M. Jespersgaard C. Andresen B.S. Borglum A.D. Pedersen S. Bolund L. Gregersen N. Bross P.
TitleHuman and mouse mitochondrial orthologs of bacterial ClpX.
SourceMamm. Genome 11:899-905(2000).
PubMed ID11003706

2AuthorsBanecki B. Wawrzynow A. Puzewicz J. Georgopoulos C. Zylicz M.
TitleStructure-function analysis of the zinc-binding region of the Clpx molecular chaperone.
SourceJ. Biol. Chem. 276:18843-18848(2001).
PubMed ID11278349

3AuthorsWojtyra U.A. Thibault G. Tuite A. Houry W.A.
TitleThe N-terminal zinc binding domain of ClpX is a dimerization domain that modulates the chaperone function.
SourceJ. Biol. Chem. 278:48981-48990(2003).
PubMed ID12937164

4AuthorsDonaldson L.W. Wojtyra U. Houry W.A.
TitleSolution structure of the dimeric zinc binding domain of the chaperone ClpX.
SourceJ. Biol. Chem. 278:48991-48996(2003).
PubMed ID14525985

5AuthorsThibault G. Houry W.A.
TitleRole of the N-terminal domain of the chaperone ClpX in the recognition and degradation of lambda phage protein O.
SourceJ. Phys. Chem. B. 116:6717-6724(2012).
PubMed ID22360725

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