title: Structural basis of the signalling through a bacterial membrane receptor HasR deciphered by an integrative approach.
abstract: Bacteria use diverse signalling pathways to adapt gene expression to external stimuli. In Gram-negative bacteria, the binding of scarce nutrients to membrane transporters triggers a signalling process that up-regulates the expression of genes of various functions, from uptake of nutrient to production of virulence factors. Although proteins involved in this process have been identified, signal transduction through this family of transporters is not well understood. In the present study, using an integrative approach (EM, SAXS, X-ray crystallography and NMR), we have studied the structure of the haem transporter HasR captured in two stages of the signalling process, i.e. before and after the arrival of signalling activators (haem and its carrier protein). We show for the first time that the HasR domain responsible for signal transfer: (i) is highly flexible in two stages of signalling; (ii) extends into the periplasm at approximately 70-90 Å (1 Å=0.1 nm) from the HasR β-barrel; and (iii) exhibits local conformational changes in response to the arrival of signalling activators. These features would favour the signal transfer from HasR to its cytoplasmic membrane partners.
authors.affiliation: Département de Biologie Structurale et Chimie, Unité de Résonance Magnétique Nucléaire des Biomolécules, Institut Pasteur, Paris, France CNRS, UMR 3528, Paris, France.
authors.forename: Halina
authors.initials: H
authors.lastname: Wojtowicz
authors.affiliation: Département de Biologie Structurale et Chimie, Unité de Résonance Magnétique Nucléaire des Biomolécules, Institut Pasteur, Paris, France CNRS, UMR 3528, Paris, France.
authors.forename: Ada
authors.initials: A
authors.lastname: Prochnicka-Chalufour
authors.affiliation: Département de Biologie Structurale et Chimie, Unité de Résonance Magnétique Nucléaire des Biomolécules, Institut Pasteur, Paris, France CNRS, UMR 3528, Paris, France.
authors.forename: Gisele Cardoso
authors.initials: GC
authors.lastname: de Amorim
authors.affiliation: Beamline SWING, Synchrotron SOLEIL, Saint-Aubin, France.
authors.forename: Olga
authors.initials: O
authors.lastname: Roudenko
authors.affiliation: Département de Biologie Structurale et Chimie, Unité de Résonance Magnétique Nucléaire des Biomolécules, Institut Pasteur, Paris, France CNRS, UMR 3528, Paris, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Simenel
authors.affiliation: Département de Biologie Structurale et Chimie, Unité de Résonance Magnétique Nucléaire des Biomolécules, Institut Pasteur, Paris, France CNRS, UMR 3528, Paris, France.
authors.forename: Idir
authors.initials: I
authors.lastname: Malki
authors.affiliation: CNRS, UMR 3528, Paris, France CITECH, Institut Pasteur, Paris, France.
authors.forename: Gérard
authors.initials: G
authors.lastname: Pehau-Arnaudet
authors.affiliation: CNRS, UMR 3528, Paris, France G5 Biologie Structurale de la Sécrétion Bactérienne, Institut Pasteur, Paris, France.
authors.forename: Francesca
authors.initials: F
authors.lastname: Gubellini
authors.affiliation: Jülich Centre for Neutron Science, Forschungszentrum Jülich GmbH, Outstation at MLZ, Garching, Germany.
authors.forename: Alexandros
authors.initials: A
authors.lastname: Koutsioubas
authors.affiliation: Beamline SWING, Synchrotron SOLEIL, Saint-Aubin, France.
authors.forename: Javier
authors.initials: J
authors.lastname: Pérez
authors.affiliation: Institut de Biologie Physico-Chimique, CNRS Université Paris-Diderot, UMR 7099, Paris, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Delepelaire
authors.affiliation: Département de Biologie Structurale et Chimie, Unité de Résonance Magnétique Nucléaire des Biomolécules, Institut Pasteur, Paris, France CNRS, UMR 3528, Paris, France.
authors.forename: Muriel
authors.initials: M
authors.lastname: Delepierre
authors.affiliation: Département de Biologie Structurale et Chimie, Unité de Résonance Magnétique Nucléaire des Biomolécules, Institut Pasteur, Paris, France CNRS, UMR 3528, Paris, France G5 Biologie Structurale de la Sécrétion Bactérienne, Institut Pasteur, Paris, France.
authors.forename: Rémi
authors.initials: R
authors.lastname: Fronzes
authors.affiliation: Département de Biologie Structurale et Chimie, Unité de Résonance Magnétique Nucléaire des Biomolécules, Institut Pasteur, Paris, France CNRS, UMR 3528, Paris, France nadia.izadi@pasteur.fr.
authors.forename: Nadia
authors.initials: N
authors.lastname: Izadi-Pruneyre
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D018360:Crystallography, X-Ray; D006418:Heme / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D026901:Membrane Transport Proteins / Q000737:chemistry* / Q000378:metabolism*; D008854:Microscopy, Electron; D011485:Protein Binding; D012706:Serratia marcescens / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; D006418:Heme
keywords: HasR; Serratia marcescens; bacterial nutrient transporter; haem; integrative approach; transmembrane signalling