title: Elongated structure of the outer-membrane activator of peptidoglycan synthesis LpoA: implications for PBP1A stimulation.
abstract: The bacterial cell envelope contains the stress-bearing peptidoglycan layer, which is enlarged during cell growth and division by membrane-anchored synthases guided by cytoskeletal elements. In Escherichia coli, the major peptidoglycan synthase PBP1A requires stimulation by the outer-membrane-anchored lipoprotein LpoA. Whereas the C-terminal domain of LpoA interacts with PBP1A to stimulate its peptide crosslinking activity, little is known about the role of the N-terminal domain. Herein we report its NMR structure, which adopts an all-α-helical fold comprising a series of helix-turn-helix tetratricopeptide-repeat (TPR)-like motifs. NMR spectroscopy of full-length LpoA revealed two extended flexible regions in the C-terminal domain and limited, if any, flexibility between the N- and C-terminal domains. Analytical ultracentrifugation and small-angle X-ray scattering results are consistent with LpoA adopting an elongated shape, with dimensions sufficient to span from the outer membrane through the periplasm to interact with the peptidoglycan synthase PBP1A.
authors: University Grenoble Alpes, Institut de Biologie Structurale, F-38027 Grenoble, France; CEA, DSV, Institut de Biologie Structurale, F-38027 Grenoble, France; CNRS, Institut de Biologie Structurale, F-38027 Grenoble, France.
authors: Nicolas L
authors: NL
authors: Jean
authors: University Grenoble Alpes, Institut de Biologie Structurale, F-38027 Grenoble, France; CEA, DSV, Institut de Biologie Structurale, F-38027 Grenoble, France; CNRS, Institut de Biologie Structurale, F-38027 Grenoble, France.
authors: Catherine M
authors: CM
authors: Bougault
authors: The Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Richardson Road, Newcastle upon Tyne NE2 4AX, UK.
authors: Adam
authors: A
authors: Lodge
authors: The Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Richardson Road, Newcastle upon Tyne NE2 4AX, UK.
authors: Adeline
authors: A
authors: Derouaux
authors: The Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Richardson Road, Newcastle upon Tyne NE2 4AX, UK.
authors: Gilles
authors: G
authors: Callens
authors: The Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Richardson Road, Newcastle upon Tyne NE2 4AX, UK.
authors: Alexander J F
authors: AJ
authors: Egan
authors: University Grenoble Alpes, Institut de Biologie Structurale, F-38027 Grenoble, France; CEA, DSV, Institut de Biologie Structurale, F-38027 Grenoble, France; CNRS, Institut de Biologie Structurale, F-38027 Grenoble, France.
authors: Isabel
authors: I
authors: Ayala
authors: Institute for Cell and Molecular Biosciences, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK.
authors: Richard J
authors: RJ
authors: Lewis
authors: The Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Richardson Road, Newcastle upon Tyne NE2 4AX, UK. Electronic address: w.vollmer@ncl.ac.uk.
authors: Waldemar
authors: W
authors: Vollmer
authors: University Grenoble Alpes, Institut de Biologie Structurale, F-38027 Grenoble, France; CEA, DSV, Institut de Biologie Structurale, F-38027 Grenoble, France; CNRS, Institut de Biologie Structurale, F-38027 Grenoble, France. Electronic address: jean-pierre.simorre@ibs.fr.
authors: Jean-Pierre
authors: JP
authors: Simorre
mesh_terms: D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008074:Lipoproteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D046915:Penicillin-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D010457:Peptidoglycan / Q000096:biosynthesis*; D019897:Periplasm / Q000378:metabolism; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D053838:Scattering, Small Angle; D017386:Sequence Homology, Amino Acid; D013696:Temperature; D014961:X-Ray Diffraction
chemical_list: D001425:Bacterial Outer Membrane Proteins; D029968:Escherichia coli Proteins; D008074:Lipoproteins; C000597255:LpoA protein, E coli; D046915:Penicillin-Binding Proteins; D010457:Peptidoglycan