title: Protein oxidation in the intermembrane space of mitochondria is substrate-specific rather than general.
abstract: In most cellular compartments cysteine residues are predominantly reduced. However, in the bacterial periplasm, the ER and the mitochondrial intermembrane space (IMS), sulfhydryl oxidases catalyze the formation of disulfide bonds. Nevertheless, many IMS proteins contain reduced cysteines that participate in binding metal- or heme-cofactors. In this study, we addressed the substrate specificity of the mitochondrial protein oxidation machinery. Dre2 is a cysteine-rich protein that is located in the cytosol. A large fraction of Dre2 bound to the cytosolic side of the outer membrane of mitochondria. Even when Dre2 is artificially targeted to the IMS, its cysteine residues remain in the reduced state. This indicates that protein oxidation in the IMS of mitochondria is not a consequence of the apparent oxidizing environment in this compartment but rather is substrate-specific and determined by the presence of Mia40-binding sites.
authors.affiliation: Cell Biology, University of Kaiserslautern, Erwin-Schrödinger-Strasse 13, 67663 Kaiserslautern, Germany.
authors.forename: Valentina
authors.initials: V
authors.lastname: Peleh
authors.affiliation: Cellular Biochemistry, University of Kaiserslautern, Erwin-Schrödinger-Strasse 13, 67663 Kaiserslautern, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Riemer
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, University of Pennsylvania, 421 Curie Blvd., Philadelphia PA 19104, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Dancis
authors.affiliation: Cell Biology, University of Kaiserslautern, Erwin-Schrödinger-Strasse 13, 67663 Kaiserslautern, Germany.
authors.forename: Johannes M
authors.initials: JM
authors.lastname: Herrmann
keywords: Dre2; Fe-S clusters; Mia40; cysteine oxidation; disulfide bonds; mitochondria; oxidative protein folding