Effect of divalent cations on the molecular structure of the GroEL oligomer.

Détails

ID Serval
serval:BIB_CDCB53204208
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Effect of divalent cations on the molecular structure of the GroEL oligomer.
Périodique
Biochemistry
Auteur(s)
Azem A., Diamant S., Goloubinoff P.
ISSN
0006-2960 (Print)
ISSN-L
0006-2960
Statut éditorial
Publié
Date de publication
1994
Volume
33
Numéro
21
Pages
6671-6675
Langue
anglais
Résumé
Structural analysis, by chemical cross-linking with glutardialdehyde (GA), and by urea denaturation, was carried out for the chaperonin oligomer GroEL14 from Escherichia coli. The cross-linking reaction of GroEL14 presents two phases: a rapid intralayer cross-linking reaction, which first occurs between the monomers of individual GroEL7 heptameric rings, and a slow interlayer cross-linking reaction, which later occurs between the two stacked heptameric rings of the GroEL14 oligomer. The biphasic behavior of the cross-linking reaction indicates that the surfaces of contact between GroEL monomers within individual heptameric rings are more extensive than the surfaces of contact between the two GroEL7 rings of the oligomer. Millimolar amounts of the divalent cations Mg2+, Mn2+, Ca2+, or Zn2+, but not of monovalent ions, increase the velocity of both intra- and interlayer cross linking. Divalent cations increase the stability of the native GroEL14 oligomer in urea. In contrast, Mg2+ activates ATP hydrolysis by GroEL14, with an activation constant in the micromolar range, while Ca2+ does not significantly assist ATP hydrolysis. It is concluded that divalent cations affect the structure of GroEL14 in particular the contacts between monomers within the GroEL7 heptameric layers. The effect of divalent cations on the structure of the chaperonin molecule is quantitatively and qualitatively distinct from that of magnesium ions on the chaperonin ATPase activity.
Mots-clé
Adenosine Triphosphatases/metabolism, Bacterial Proteins/chemistry, Bacterial Proteins/genetics, Cations, Divalent/chemistry, Chaperonin 60, Cloning, Molecular, Cross-Linking Reagents, Escherichia coli/genetics, Heat-Shock Proteins/chemistry, Heat-Shock Proteins/genetics, Kinetics, Protein Conformation, Recombinant Proteins/chemistry, Recombinant Proteins/genetics, Urea
Pubmed
Web of science
Création de la notice
24/01/2008 21:02
Dernière modification de la notice
20/08/2019 16:48
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