title: Cardiolipin-based respiratory complex activation in bacteria.
abstract: Anionic lipids play a variety of key roles in membrane function, including functional and structural effects on respiratory complexes. However, little is known about the molecular basis of these lipid-protein interactions. In this study, NarGHI, an anaerobic respiratory complex of Escherichia coli, has been used to investigate the relations in between membrane-bound proteins with phospholipids. Activity of the NarGHI complex is enhanced by anionic phospholipids both in vivo and in vitro. The anionic cardiolipin tightly associates with the NarGHI complex and is the most effective phospholipid to restore functionality of a nearly inactive detergent-solubilized enzyme complex. A specific cardiolipin-binding site is identified on the basis of the available X-ray diffraction data and of site-directed mutagenesis experiment. One acyl chain of cardiolipin is in close proximity to the heme b(D) center and is responsible for structural adjustments of b(D) and of the adjacent quinol substrate binding site. Finally, cardiolipin binding tunes the interaction with the quinol substrate. Together, our results provide a molecular basis for the activation of a bacterial respiratory complex by cardiolipin.
authors.affiliation: Laboratoire de Chimie Bactérienne, Unité Propre de Recherche 9043, Institut de Microbiologie de la Méditerranée, Centre National de la Recherche Scientifique and Aix-Marseille Université, 31, Chemin Joseph Aiguier, 13009 Marseille, France.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Arias-Cartin
authors.forename: Stéphane
authors.initials: S
authors.lastname: Grimaldi
authors.forename: Janine
authors.initials: J
authors.lastname: Pommier
authors.forename: Pascal
authors.initials: P
authors.lastname: Lanciano
authors.forename: Cédric
authors.initials: C
authors.lastname: Schaefer
authors.forename: Pascal
authors.initials: P
authors.lastname: Arnoux
authors.forename: Gérard
authors.initials: G
authors.lastname: Giordano
authors.forename: Bruno
authors.initials: B
authors.lastname: Guigliarelli
authors.forename: Axel
authors.initials: A
authors.lastname: Magalon
mesh_terms: D001665:Binding Sites; D002308:Cardiolipins / Q000737:chemistry / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy; D045222:Electron Transport Chain Complex Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006418:Heme / Q000737:chemistry; D008563:Membrane Lipids / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D009097:Multienzyme Complexes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D050505:Mutant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D050901:Nitrate Reductase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010088:Oxidoreductases / Q000737:chemistry / Q000378:metabolism; D010743:Phospholipids / Q000737:chemistry / Q000378:metabolism; D054730:Protein Interaction Domains and Motifs; D011510:Proteolipids / Q000378:metabolism; D055672:Static Electricity
chemical_list: D002308:Cardiolipins; D045222:Electron Transport Chain Complex Proteins; D029968:Escherichia coli Proteins; D008563:Membrane Lipids; D009097:Multienzyme Complexes; D050505:Mutant Proteins; D010743:Phospholipids; D011510:Proteolipids; C020485:proteoliposomes; D006418:Heme; D010088:Oxidoreductases; C020094:duroquinol oxidase; C508365:NarG protein, E coli; D050901:Nitrate Reductase