Effect of free and ATP-bound magnesium and manganese ions on the ATPase activity of chaperonin GroEL14.

Détails

ID Serval
serval:BIB_1E3BA3D7D1AB
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Effect of free and ATP-bound magnesium and manganese ions on the ATPase activity of chaperonin GroEL14.
Périodique
Biochemistry
Auteur(s)
Diamant S., Azem A., Weiss C., Goloubinoff P.
ISSN
0006-2960 (Print)
ISSN-L
0006-2960
Statut éditorial
Publié
Date de publication
1995
Volume
34
Numéro
1
Pages
273-277
Langue
anglais
Résumé
Hydrolysis of ATP by the GroEL14 chaperonin oligomer is activated and modulated by Mg2+ or Mn2+ ions. Mg-ATP and Mn-ATP can serve as substrates of the reaction and bind in a positively cooperative manner to the same catalytic sites on GroEL14, with similar binding constants in the micromolar range. In addition, millimolar amounts of Mg2+ and Mn2+ ions can further activate the GroEL14-ATPase while interacting with low-affinity noncatalytic sites on the chaperonin. The extent of ATPase activation by Mn2+ is half of that by Mg2+ ions. When both Mg2+ and Mn2+ ions are present in the same reaction, Mn2+ behaves as a noncompetitive partial inhibitor of the Mg-dependent ATPase. This inhibition requires the presence of ADP in the catalytic site. The binding affinity of Mn-ADP to the site is significantly higher than that of Mg-ADP. A slower release of Mn-ADP from the catalytic site thus changes the rate-determining step of the GroEL14-ATPase cycle. In the cell, the concentrations of Mg2+ and Mn2+ ions are such that both divalent ions may modulate chaperonin activity.
Mots-clé
Adenosine Triphosphatases/drug effects, Adenosine Triphosphatases/metabolism, Adenosine Triphosphate/metabolism, Binding Sites, Ca(2+) Mg(2+)-ATPase/antagonists & inhibitors, Chaperonin 60/drug effects, Chaperonin 60/metabolism, Enzyme Activation, Hydrolysis, Kinetics, Magnesium/metabolism, Magnesium/pharmacology, Manganese/metabolism, Manganese/pharmacology
Pubmed
Web of science
Création de la notice
24/01/2008 21:02
Dernière modification de la notice
20/08/2019 13:54
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