Involvement of the interdomain hydrophobic linker and the C-terminal helices in self-association of the molecular chaperone HSC70.
HSP70 from bacteria to man are known to self-associate to form multiple species suggesting that self-association is related to function. In order to determine the structural basis of HSP70 oligomerization, deletion mutants in the C-terminal domain of HSC70, a constitutive member of the HSP70 family, have been constructed and analyzed for their self-association properties by gel electrophoresis, size-exclusion chromatography and analytical ultracentrifugation. The results of this investigation indicate that, whereas deletion of the GGMP rich C-terminal extremity of HSC70, containing EEVD motif stabilizes the oligomeric species, deletions of either the aD-aE C-terminal helices or the inter-domain hydrophobic linker contribute to the stabilization of the monomeric form. Thus, two non-contiguous regions, located at both ends of the C-terminal domain of the protein, appear to form the contact interface in the oligomers and may interact in a dynamic fashion leading to the formation of several coexisting species.
Amor-Mahjoub
M
M
Laboratory of Biochemistry of Cellular and Molecular Signals, FRE 2621, CNRS- University P. & M. Curie, 96 Bd Raspail, 75006 Paris, France. mounamor@yahoo.fr
Gomez-Vrielyunck
N
N
Suppini
J P
JP
Fouchaq
B
B
Benarouj
N
N
Ladjimi
M
M
D000818:Animals; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D050883:HSC70 Heat-Shock Proteins / Q000737:chemistry* / Q000235:genetics; D057927:Hydrophobic and Hydrophilic Interactions; D016297:Mutagenesis, Site-Directed; D050505:Mutant Proteins / Q000737:chemistry / Q000235:genetics; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D051381:Rats; D020449:Repetitive Sequences, Amino Acid; D017384:Sequence Deletion; D014461:Ultracentrifugation
D050883:HSC70 Heat-Shock Proteins; C494373:Hspa8 protein, rat; D050505:Mutant Proteins