NDUFS6 is a subunit of the NADH:ubiquinone oxidoreductase (complex I), which is the first enzyme complex in the electron transport chain of mitochondria. This complex functions in the transfer of electrons from NADH to the respiratory chain. The subunit is one of seven subunits in the iron-sulfur protein fraction. Mutations cause mitochondrial complex I deficiency, a disease that causes a wide variety of clinical disorders, including neonatal disease and adult-onset neurodegenerative disorders. Recombinant human NDUFS6 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques