PMID:12475930
| Citation |
D'Autreaux, B, Touati, D, Bersch, B, Latour, JM and Michaud-Soret, I (2002) Direct inhibition by nitric oxide of the transcriptional ferric uptake regulation protein via nitrosylation of the iron. Proc. Natl. Acad. Sci. U.S.A. 99:16619-24 |
|---|---|
| Abstract |
Ferric uptake regulation protein (Fur) is a bacterial global regulator that uses iron as a cofactor to bind to specific DNA sequences. The function of Fur is not limited to iron homeostasis. A wide variety of genes involved in various mechanisms such as oxidative and acid stresses are under Fur control. Flavohemoglobin (Hmp) is an NO-detoxifying enzyme induced by NO and nitrosothiol compounds. Fur recently was found to regulate hmp in Salmonella typhimurium, and in Escherichia coli, the iron-chelating agent 2,2'-dipyridyl induces hmp expression. We now establish direct inhibition of E. coli Fur activity by NO. By using chromosomal Fur-regulated lacZ reporter fusion in E. coli, Fur activity is switched off by NO at micromolar concentration. In vitro Fur DNA-binding activity, as measured by protection of restriction site in aerobactin promoter, is directly sensitive to NO. NO reacts with Fe(II) in purified FeFur protein to form a S = 12 low-spin FeFur-NO complex with a g = 2.03 EPR signal. Appearance of the same EPR signal in NO-treated cells links nitrosylation of the iron with Fur inhibition. The nitrosylated Fur protein is still a dimer and is stable in anaerobiosis but slowly decays in air. This inhibition probably arises from a conformational switch, leading to an inactive dimeric protein. These data establish a link between control of iron metabolism and the response to NO effects. |
| Links |
PubMed PMC139193 Online version:10.1073/pnas.252591299 |
| Keywords |
Bacterial Proteins/antagonists & inhibitors; Bacterial Proteins/chemistry; Bacterial Proteins/physiology; Dimerization; Electron Spin Resonance Spectroscopy; Escherichia coli; Iron/metabolism; Nitric Oxide/physiology; Protein Conformation; Repressor Proteins/antagonists & inhibitors; Repressor Proteins/chemistry; Repressor Proteins/physiology; Transcription, Genetic |
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