The biosynthesis of iron-sulfur clusters (Fe-S) is realized by a system of genes/proteins that are quite similar in bacterial and mitochondria. This system is called ISC (for iron-sulfur cluster) basically consists of 7 proteins that are all expressed together in one operon.
- HscA & HscB
- IscA, IscS, IscU & IscX
- Fdx
Additionally a regulatory protein, IscR can be found around that operon.
Function of each element:
- IscS: desulfurase: extracts the sulfur from the cysteines and donate it to IscU
- IscX: seems to be involved in the recruitment of iron and the regulation of IscS
- IscU & IscA: IscU is the active subunit, that has two different states with lifetime of 1 sec. each –> together with IscA, this complex is arranging the iron-sulfur scaffold
- HscA & HscB are chaperon proteins, that deliver the protein, fold it and transport it to the place to working
- Fdx: Ferredoxin, which provides the electrons for the processes
- Zinc seems to stabilize the biosynthesis assembly machinery
Cheat Sheets for Computational Biochemistry 