The small heat-shock protein IbpB from Escherichia coli stabilizes stress-denatured proteins for subsequent refolding by a multichaperone network.

Details

Serval ID
serval:BIB_8C200325B867
Type
Article: article from journal or magazin.
Collection
Publications
Title
The small heat-shock protein IbpB from Escherichia coli stabilizes stress-denatured proteins for subsequent refolding by a multichaperone network.
Journal
Journal of Biological Chemistry
Author(s)
Veinger L., Diamant S., Buchner J., Goloubinoff P.
ISSN
0021-9258 (Print)
ISSN-L
0021-9258
Publication state
Published
Issued date
1998
Volume
273
Number
18
Pages
11032-11037
Language
english
Abstract
The role of small heat-shock proteins in Escherichia coli is still enigmatic. We show here that the small heat-shock protein IbpB is a molecular chaperone that assists the refolding of denatured proteins in the presence of other chaperones. IbpB oligomers bind and stabilize heat-denatured malate dehydrogenase (MDH) and urea-denatured lactate dehydrogenase and thus prevent the irreversible aggregation of these proteins during stress. While IbpB-stabilized proteins alone do not refold spontaneously, they are specifically delivered to the DnaK/DnaJ/GrpE (KJE) chaperone system where they refold in a strict ATPase-dependent manner. Although GroEL/GroES (LS) chaperonins do not interact directly with IbpB-released proteins, LS accelerate the rate of KJE-mediated refolding of IbpB-released MDH, and to a lesser extent lactate dehydrogenase, by rapidly processing KJE-released early intermediates. Kinetic and gel-filtration analysis showed that denatured MDH preferentially transfers from IbpB to KJE, then from KJE to LS, and then forms a active enzyme. IbpB thus stabilizes aggregation-prone folding intermediates during stress and, as an integral part of a cooperative multichaperone network, is involved in the active refolding of stress-denatured proteins.
Keywords
Adenosine Triphosphate/metabolism, Chaperonin 60/genetics, Chaperonins/metabolism, Chromatography, Gel, Escherichia coli/metabolism, Escherichia coli Proteins, Heat-Shock Proteins/metabolism, Kinetics, Mutation, Oxidative Stress, Protein Denaturation, Protein Folding
Pubmed
Web of science
Open Access
Yes
Create date
24/01/2008 21:02
Last modification date
08/05/2019 21:44
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