PMID:18618270

Citation	Bitoun, JP, Wu, G and Ding, H (2008) Escherichia coli FtnA acts as an iron buffer for re-assembly of iron-sulfur clusters in response to hydrogen peroxide stress. Biometals 21:693-703
Abstract	Iron-sulfur clusters are one of the most ubiquitous redox centers in biology. Ironically, iron-sulfur clusters are highly sensitive to reactive oxygen species. Disruption of iron-sulfur clusters will not only change the activity of proteins that host iron-sulfur clusters, the iron released from the disrupted iron-sulfur clusters will further promote the production of deleterious hydroxyl free radicals via the Fenton reaction. Here, we report that ferritin A (FtnA), a major iron-storage protein in Escherichia coli, is able to scavenge the iron released from the disrupted iron-sulfur clusters and alleviates the production of hydroxyl free radicals. Furthermore, we find that the iron stored in FtnA can be retrieved by an iron chaperon IscA for the re-assembly of the iron-sulfur cluster in a proposed scaffold IscU in the presence of the thioredoxin reductase system which emulates normal intracellular redox potential. The results suggest that E. coli FtnA may act as an iron buffer to sequester the iron released from the disrupted iron-sulfur clusters under oxidative stress conditions and to facilitate the re-assembly of the disrupted iron-sulfur clusters under normal physiological conditions.
Links	PubMed PMC2576483 Online version:10.1007/s10534-008-9154-7
Keywords	Apoproteins/metabolism; Buffers; Carrier Proteins/metabolism; Escherichia coli/drug effects; Escherichia coli/metabolism; Escherichia coli Proteins/metabolism; Escherichia coli Proteins/physiology; Ferritins/physiology; Hydrogen Peroxide/pharmacology; Hydroxyl Radical/metabolism; Iron/metabolism; Iron-Sulfur Proteins/biosynthesis; Iron-Sulfur Proteins/metabolism; Stress, Physiological
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
ECOLI:FTNA		GO:0006979: iron-sulfur cluster assembly	ECO:0000314:		P		Fig. 3 shows that FtnA releaves the production of hydroxyl free radicals by scavenging the iron	complete CACAO 2863
ECOLI:FTNA		GO:0034986: iron chaperone activity	ECO:0000314:		F		Figure 6 shows that IscA can retrieve iron from the iron-bound FtnA.	complete
ECOLI:FTNA	involved_in	GO:0006979: response to oxidative stress	ECO:0000314: direct assay evidence used in manual assertion		P		Seeded From UniProt	complete

References

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