Titre
The small heat-shock protein IbpB from Escherichia coli stabilizes stress-denatured proteins for subsequent refolding by a multichaperone network.
Type
article
Institution
Externe
Périodique
Auteur(s)
Veinger, L.
Auteure/Auteur
Diamant, S.
Auteure/Auteur
Buchner, J.
Auteure/Auteur
Goloubinoff, P.
Auteure/Auteur
Liens vers les personnes
ISSN
0021-9258
Statut éditorial
Publié
Date de publication
1998
Volume
273
Numéro
18
Première page
11032
Dernière page/numéro d’article
11037
Langue
anglais
Résumé
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.
PID Serval
serval:BIB_8C200325B867
PMID
Open Access
Oui
Date de création
2008-01-24T19:02:28.323Z
Date de création dans IRIS
2025-05-20T21:01:36Z