PMID:10982797

Citation	Barnett, ME, Zolkiewska, A and Zolkiewski, M (2000) Structure and activity of ClpB from Escherichia coli. Role of the amino-and -carboxyl-terminal domains. J. Biol. Chem. 275:37565-71
Abstract	ClpB is a member of a protein-disaggregating multi-chaperone system in Escherichia coli. The mechanism of protein-folding reactions mediated by ClpB is currently unknown, and the functional role of different sequence regions in ClpB is under discussion. We have expressed and purified the full-length ClpB and three truncated variants with the N-terminal, C-terminal, and a double N- and C-terminal deletion. We studied the protein concentration-dependent and ATP-induced oligomerization of ClpB, casein-induced activation of ClpB ATPase, and ClpB-assisted reactivation of denatured firefly luciferase. We found that both the N- and C-terminal truncation of ClpB strongly inhibited its chaperone activity. The reasons for such inhibition were different, however, for the N- and C-terminal truncation. Deletion of the C-terminal domain inhibited the self-association of ClpB, which led to decreased affinity for ATP and to decreased ATPase and chaperone activity of the C-terminally truncated variants. In contrast, deletion of the N-terminal domain did not inhibit the self-association of ClpB and its basal ATPase activity but decreased the ability of casein to activate ClpB ATPase. These results indicate that the N-terminal region of ClpB may contain a functionally significant protein-binding site, whereas the main role of the C-terminal region is to support oligomerization of ClpB.
Links	PubMed PMC1819559 Online version:10.1074/jbc.M005211200
Keywords	Adenosine Triphosphatases/metabolism; Circular Dichroism; Escherichia coli/metabolism; Escherichia coli Proteins; Heat-Shock Proteins/chemistry; Heat-Shock Proteins/metabolism; Molecular Chaperones/metabolism; Structure-Activity Relationship
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
PSYA2:Q4FTI2		GO:0019538: protein metabolic process	ECO:0000315:		P		Fig. 6 illustrates the amount of ATP hydrolysis by clpB mutants and wild types.	complete CACAO 9566
ECOBD:C6EJZ8		GO:0019538: protein metabolic process	ECO:0000315:		P		Fig. 6 illustrates the amount of ATP hydrolysis by clpB mutants and wild types.	complete CACAO 9611

References

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