Nitrite Causes Nitrosative Stress to Iron Sulfur Clusters.

Nitric oxide (NO), produced by nitrite reductases or nitric oxide synthases, performs vital roles in signaling and the immune response. Iron sulfur (FeS) clusters are known targets for NO induced degradation, serving as sensors to trigger cellular responses. However, this FeS reactivity is proposed as NO specific, with no demonstrated reactivity toward nitrite, a soluble NO storage molecule. We demonstrate that synthetic FeS clusters supported by various ligands undergo facile nitrosylation by nitrite in the presence of a reductant, evidencing the nitrite reductase reactivity for FeS clusters. Moreover, a mononitrosylated Fe4S4 cluster, [tempS3Fe4S4(NO)]2-, can be readily synthesized by this approach, enabling further investigation into the FeS cluster repair and decomposition under NO induced oxidative stress.