Divalent cations stabilize GroEL under conditions of oxidative stress

The divalent cations Mg2+, Mn2+, Zn2+, Ca2+, and Ni2+ were found to protect against proteolysis a form of GroEL (ox-GroEL) prepared by exposing GroEL for 16h to 6mM hydrogen peroxide (H2O2). K+ and other monovalent cations did not have any effect. Divalent cations also induced a conformational chang...

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Bibliographic Details
Published in:Biochemical and biophysical research communications 2008-04, Vol.368 (3), p.625-630
Main Authors: Melkani, Girish C., Sielaff, Robin L., Zardeneta, Gustavo, Mendoza, Jose A.
Format: Article
Language:English
Subjects:
Cations
Chaperonin
Chaperonin 60 - chemistry
GroEL
Hydrogen peroxide
Hydrogen Peroxide - chemistry
Oxidative Stress
Oxygen - chemistry
Reactivation
Rhodanese
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Summary:The divalent cations Mg2+, Mn2+, Zn2+, Ca2+, and Ni2+ were found to protect against proteolysis a form of GroEL (ox-GroEL) prepared by exposing GroEL for 16h to 6mM hydrogen peroxide (H2O2). K+ and other monovalent cations did not have any effect. Divalent cations also induced a conformational change of ox-GroEL that led to the decrease of its large exposed hydrophobic surfaces (exposed with H2O2). Ox-GroEL incubated with a divalent cation behaved like N-GroEL in that it could transiently interact with H2O2-inactivated rhodanese (ox-rhodanese), whereas ox-GroEL alone could strongly interact with ox-rhodanese. Although, ox-GroEL incubated with a divalent cation could not recover the ATPase activity (66%) lost with H2O2, it could facilitate the reactivation of ox-rhodanese (>86% of active rhodanese recovered), without requiring ATP or the co-chaperonin, GroES. This is the first report to demonstrate a role for the divalent cations on the structure and function of ox-GroEL.
ISSN:0006-291X
1090-2104
DOI:10.1016/j.bbrc.2008.01.126