NADH dehydrogenase [ubiquinone] iron-sulfur protein 2, mitochondrial isoform 1 precursor, also known as NDUFS2, is a 463 amino acid protein that is suggested to be required for catalytic activity. Defects in NDUFS2 are the cause of complex I mitochondrial respiratory chain deficiency, which is characterized by a variety of symptoms including liver failure, cardiomyopathy and neurodegeneration. Located in the mitochondrial inner membrane, mitochondrial complex I is the first and largest enzyme in the electron transport chain of oxidative phosphorylation. Recombinant human NDUFS2 protein, fused to His-tag at N-terminus, was expressed in E.coli.