title: Involvement of Acidic Amino Acid Residues in Zn(2+) Binding to Respiratory Complex I.
abstract: Proton transfer across membranes and membrane proteins is a central process in biological systems. Zn(2+) ions are capable of binding to acidic residues, often found within such specific pathways, thereby leading to a blockage. Here we probed Zn(2+) inhibition of the proton-pumping NADH:ubiquinone oxidoreductase from Escherichia coli by means of electrochemically induced FTIR difference spectroscopy. Numerous conformational changes were identified including those that arise from the reorganization of the membrane arm upon electron transfer in the peripheral arm of the protein. Signals at very high wavenumbers (1781 and 1756 cm(-1)) point to the perturbation of acidic residues in a highly hydrophobic environment upon Zn(2+) binding. In variant D563N(L), which lacks part of the proton pumping activity (residue located on the horizontal amphipathic helix), the spectral signature of Zn(2+) binding is changed. Our data support a role for this residue in proton translocation.
authors.affiliation: Laboratoire de Bioelectrochimie et Spectroscopie, UMR 7140, Chimie de la Matière Complexe, Université de Strasbourg, CNRS, 1 rue Blaise Pascal, 67070, Strasbourg, France.|Université Paris Diderot, Sorbonne Paris Cité, Laboratoire d'Electrochimie Moléculaire, Unité Mixte de Recherche Université-, CNRS No. 7591, Bâtiment Lavoisier, 15 rue Jean de Baïf, 75205, Paris Cedex 13, France.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Kriegel
authors.affiliation: Laboratoire de Bioelectrochimie et Spectroscopie, UMR 7140, Chimie de la Matière Complexe, Université de Strasbourg, CNRS, 1 rue Blaise Pascal, 67070, Strasbourg, France.
authors.forename: Batoul
authors.initials: B
authors.lastname: Srour
authors.affiliation: Albert-Ludwigs-Universität Freiburg, Institut für Biochemie, Albertstrasse 21, 79104, Freiburg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Steimle
authors.affiliation: Albert-Ludwigs-Universität Freiburg, Institut für Biochemie, Albertstrasse 21, 79104, Freiburg, Germany.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Friedrich
authors.affiliation: Laboratoire de Bioelectrochimie et Spectroscopie, UMR 7140, Chimie de la Matière Complexe, Université de Strasbourg, CNRS, 1 rue Blaise Pascal, 67070, Strasbourg, France. hellwig@unistra.fr.
authors.forename: Petra
authors.initials: P
authors.lastname: Hellwig
mesh_terms: D002413:Cations, Divalent / Q000378:metabolism; D042967:Electron Transport Complex I / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D009154:Mutation; D011487:Protein Conformation; D011522:Protons; D015032:Zinc / Q000378:metabolism*
chemical_list: D002413:Cations, Divalent; D011522:Protons; D042967:Electron Transport Complex I; D015032:Zinc
keywords: IR spectroscopy; Zn2+; complex I; infrared difference spectroscopy; inhibitors; proton pumping