Superoxide anion reacts with Fe-S cluster

Stable Identifier
R-HSA-6789109
Type
Reaction [binding]
Species
Homo sapiens
Compartment
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Iron-sulfur (Fe-S) clusters are ubiquitous, evolutionary ancient and functionally versatile prosthetic groups found in a variety of metalloproteins. In most Fe-S proteins, the clusters function as electron-transfer groups in mediating one-electron redox processes. Fe-S clusters may also participate in iron/sulfur storage or regulate enzyme activity and substrate binding. As stress sensors, Fe-S clusters may regulate gene expression. Fe-S clusters have variable compositions such as 2Fe-2S, 3Fe-4S, 4Fe-4S centers. Solvent-exposed [4Fe-4S](2+) clusters are sensitive to oxidation and can be damaged (or disassembled) by reactive oxygen species. Superoxide (O2.-) and hydrogen peroxide (H2O2) oxidize [4Fe-4S](2+) into unstable [4Fe-4S](3+) intermediate, which is degraded to a [3Fe-4S](+) cluster. This process releases free iron (Fe(2+)) and inactivates the enzyme. High concentration of Fe(2+) under oxidative stress elevates ROS toxicity by catalyzing Fenton reaction that generates hydroxyl radical (OH.) from H2O2. Hydroxyl radical reacts with all macromolecules, including proteins, peptidoglycans, lipids or DNA.

Literature References
PubMed ID Title Journal Year
  Iron-Sulfur Clusters in Chemistry and Biology

Rouault, TA

  2014
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