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Role of iron‐sulfur cluster in E. coli DinG helicase
Author(s) -
Ren Binbin,
Ding Huangen
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.lb177
Subject(s) - helicase , iron–sulfur cluster , chemistry , rna helicase a , dna , cluster (spacecraft) , biochemistry , oxidative stress , microbiology and biotechnology , gene , enzyme , biology , rna , computer science , programming language
The E. coli DinG protein encoded by the DNA damage‐inducible gene ( dinG ) is a member of the helicase superfamily 2. It has the DNA‐dependent ATPase activity and ATP‐dependent helicase activity. In this study, we report that the purified DinG protein contains a [4Fe‐4S] cluster with a midpoint redox potential ‐390±23 mV (pH 8.0). More importantly, the DinG helicase activity is inactivated when its [4Fe‐4S] is reduced and reactivated when the cluster is re‐oxidized, suggesting that the redox state of the [4Fe‐4S] cluster in DinG can modulate helicase activity. Unlike the [4F‐4S] cluster of E. coli dihydroxyacid dehydratase, the [4Fe‐4S] cluster in DinG is resistant to the oxidative stress caused by hydrogen peroxide and remains active. On the other hand, the DinG helicase activity is completely abolished by nitric oxide (NO) through modification of its 4Fe‐4S cluster and almost fully restored when the NO‐modified [4Fe‐4S] cluster is reassembled. The results suggest that the [4Fe‐4S] cluster in DinG may act as a sensor of the cellular redox potential and that the NO modification of the iron‐sulfur cluster in DinG and other DNA repair enzymes may contribute to the NO‐mediated genomic instability.