iron-sulfur cluster binding

Definition

Target type: molecularfunction

Binding to an iron-sulfur cluster, a combination of iron and sulfur atoms. [GOC:ai]

Iron-sulfur cluster binding is a molecular function that describes the interaction of proteins with iron-sulfur (Fe-S) clusters. These clusters are inorganic prosthetic groups composed of iron and sulfur atoms, often arranged in specific configurations like [2Fe-2S], [4Fe-4S], or [3Fe-4S] clusters. Fe-S clusters play a crucial role in a wide range of biological processes, including electron transfer, redox reactions, enzyme catalysis, and DNA repair.

The binding of an Fe-S cluster to a protein typically involves specific amino acid residues within the protein's structure. These residues, often cysteine or histidine, coordinate to the iron atoms of the cluster, forming a stable complex. The precise arrangement and chemical environment of the Fe-S cluster within the protein determine its specific function.

**Electron Transfer:** Fe-S clusters are excellent electron carriers due to their ability to readily gain or lose electrons. This property makes them essential components of electron transport chains, such as those found in mitochondria and chloroplasts. For instance, in respiratory complexes, Fe-S clusters facilitate the transfer of electrons from one molecule to another, ultimately leading to ATP production.

**Redox Reactions:** Fe-S clusters are involved in various redox reactions, where they act as electron donors or acceptors. In enzymes like aconitase, the Fe-S cluster participates in the reversible isomerization of citrate to isocitrate, a crucial step in the citric acid cycle.

**Enzyme Catalysis:** Many enzymes rely on Fe-S clusters for their catalytic activity. Nitrogenase, the enzyme responsible for nitrogen fixation, utilizes an intricate Fe-S cluster complex to reduce atmospheric nitrogen to ammonia. Other enzymes with Fe-S cluster-dependent activity include succinate dehydrogenase, a key enzyme in the electron transport chain, and pyruvate dehydrogenase, involved in glucose metabolism.

**DNA Repair:** Fe-S clusters are also implicated in DNA repair pathways. For example, the enzyme endonuclease III, which repairs oxidative damage to DNA, contains a [4Fe-4S] cluster involved in the cleavage of damaged DNA strands.

**Regulation:** The assembly, disassembly, and stability of Fe-S clusters are carefully regulated within the cell. Dedicated machinery, including proteins like Nfs1 and IscU, ensures proper cluster formation and delivery to target proteins.

In conclusion, iron-sulfur cluster binding is a fundamental molecular function that underpins a wide variety of essential biological processes. The diverse roles of these clusters in electron transfer, redox reactions, enzyme catalysis, and DNA repair highlight their importance for maintaining cellular function and survival.'
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Proteins (2)

Compounds (18)