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Nat Commun. 2014 Dec 17;5:5804. doi: 10.1038/ncomms6804.

Activation of RidA chaperone function by N-chlorination.

Author information

1
Institute of Biochemistry and Pathobiochemistry-Microbial Biochemistry, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany.
2
Biology of Microorganisms, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany.
3
Medizinisches Proteom-Center, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany.

Abstract

Escherichia coli RidA is a member of a structurally conserved, yet functionally highly diverse protein family involved in translation inhibition (human), Hsp90-like chaperone activity (fruit fly) and enamine/imine deamination (Salmonella enterica). Here, we show that E. coli RidA modified with HOCl acts as a highly effective chaperone. Although activation of RidA is reversed by treatment with DTT, ascorbic acid, the thioredoxin system and glutathione, it is independent of cysteine modification. Instead, treatment with HOCl or chloramines decreases the amino group content of RidA by reversibly N-chlorinating positively charged residues. N-chlorination increases hydrophobicity of RidA and promotes binding to a wide spectrum of unfolded cytosolic proteins. Deletion of ridA results in an HOCl-sensitive phenotype. HOCl-mediated N-chlorination thus is a cysteine-independent post-translational modification that reversibly turns RidA into an effective chaperone holdase, which plays a crucial role in the protection of cytosolic proteins during oxidative stress.

PMID:
25517874
PMCID:
PMC4284807
DOI:
10.1038/ncomms6804
[Indexed for MEDLINE]
Free PMC Article

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