One-step purification of the NADH dehydrogenase fragment of the Escherichia coli complex I by means of Strep-tag affinity chromatography

The proton-pumping NADH:ubiquinone oxidoreductase, also called complex I, i s the first energy-transducing complex of many respiratory chains. Complex I of Escherichia coli can be split into three fragments. One of these fragm ents, the soluble NADH dehydrogenase fragment, represents the electron inpu t part of complex I. It comprises the subunits NuoE, F and G and harbors on e flavin mononucleotide and up to six iron-sulfur clusters. Here, we report the one-step purification of this fragment bg means of affinity chromatogr aphy on StrepTactin, This was achieved by fusing the Strep-tag II peptide t o the C-terminus of NuoF or NuoG, Fusion of this peptide to the N-terminus of either NuoE or NuoF disturbed the assembly of the NADH dehydrogenase fra gment, (C) 1999 Federation of European Biochemical Societies.