Iron-sulfur clusters are well known for their functions in various oxidation-reduction reactions including mitochondrial electron transport, biosynthesis of lipid and biotin as sulfur donor, catalysis in aconitase, as well as gene regulation. This research has focused on important proteins dedicated to iron-sulfur cluster assembly such as NFU which participates in cluster biosynthesis, frataxin, and the iron-sulfur cluster scaffold protein ISU.
The thermal stabilities of the above proteins were studied by using Differential Scanning Calorimetry. Thermal profiles of each protein were obtained which allow us to understand more about the unfolding process of the N and C termini of human NFU, full length and truncated forms of frataxin, apo-ISU, holo-ferredoxin, and Thermotoga maritime IscU. We find that the C-terminus of NFU, full length frataxin, and ISU proteins exibit less stability and may contain molten globule states. While N-terminal NFU, full length NFU, truncated frataxin and T.m. IScU show greater stability with well-defined structures.
These thermostability studies via DSC provide detailed insights into various iron-sulfur assembly proteins and help us understand more deeply about their roles in cell iron metabolism.