title: Characterization of the elongasome core PBP2 : MreC complex of Helicobacter pylori.
abstract: The definition of bacterial cell shape is a complex process requiring the participation of multiple components of an intricate macromolecular machinery. We aimed at characterizing the determinants involved in cell shape of the helical bacterium Helicobacter pylori. Using a yeast two-hybrid screen with the key cell elongation protein PBP2 as bait, we identified an interaction between PBP2 and MreC. The minimal region of MreC required for this interaction ranges from amino acids 116 to 226. Using recombinant proteins, we showed by affinity and size exclusion chromatographies and surface plasmon resonance that PBP2 and MreC form a stable complex. In vivo, the two proteins display a similar spatial localization and their complex has an apparent 1:1 stoichiometry; these results were confirmed in vitro by analytical ultracentrifugation and chemical cross-linking. Small angle X-ray scattering analyses of the PBP2 : MreC complex suggest that MreC interacts directly with the C-terminal region of PBP2. Depletion of either PBP2 or MreC leads to transition into spherical cells that lose viability. Finally, the specific expression in trans of the minimal interacting domain of MreC with PBP2 in the periplasmic space leads to cell rounding, suggesting that the PBP2/MreC complex formation in vivo is essential for cell morphology.
authors.affiliation: Institut Pasteur, Group Biology and Genetics of the Bacterial Cell Wall, F-75015 Paris, France.
authors.forename: Meriem
authors.initials: M
authors.lastname: El Ghachi
authors.forename: Pierre-Jean
authors.initials: PJ
authors.lastname: Matteï
authors.forename: Chantal
authors.initials: C
authors.lastname: Ecobichon
authors.forename: Alexandre
authors.initials: A
authors.lastname: Martins
authors.forename: Sylviane
authors.initials: S
authors.lastname: Hoos
authors.forename: Christine
authors.initials: C
authors.lastname: Schmitt
authors.forename: Frédéric
authors.initials: F
authors.lastname: Colland
authors.forename: Christine
authors.initials: C
authors.lastname: Ebel
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Prévost
authors.forename: Frank
authors.initials: F
authors.lastname: Gabel
authors.forename: Patrick
authors.initials: P
authors.lastname: England
authors.forename: Andréa
authors.initials: A
authors.lastname: Dessen
authors.forename: Ivo G
authors.initials: IG
authors.lastname: Boneca
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016480:Helicobacter pylori / Q000737:chemistry / Q000166:cytology* / Q000235:genetics / Q000378:metabolism*; D050296:Microbial Viability; D008969:Molecular Sequence Data; D046915:Penicillin-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D020798:Two-Hybrid System Techniques
chemical_list: D001426:Bacterial Proteins; C062061:MreC protein, Bacteria; D046915:Penicillin-Binding Proteins