I. Levchenko et al., PDZ-LIKE DOMAINS MEDIATE BINDING-SPECIFICITY IN THE CLP HSP100 FAMILYOF CHAPERONES AND PROTEASE REGULATORY SUBUNITS/, Cell, 91(7), 1997, pp. 939-947
ClpX, a molecular chaperone and the regulatory subunit of the ClpXP pr
otease, is shown to contain tandem modular domains that bind to the C-
terminal sequences of target proteins in a manner that parallels funct
ional specificity Nuclear magnetic resonance studies show that these C
-terminal sequences are displayed as disordered peptides on the surfac
e of otherwise folded proteins. The ClpX substrate-binding domains are
homologous to sequences in other Clp/Hsp100 proteins and are related
more distantly to PDZ domains, which also mediate C-terminal specific
protein-protein interactions. Conservation of these binding domains in
dicates that the mode of substrate recognition characterized here for
ClpX will be a conserved feature among Clp/Hsp100 family members and a
distinguishing characteristic between this chaperone family and the H
sp70 chaperones.