title: Ankyrin-mediated self-protection during cell invasion by the bacterial predator Bdellovibrio bacteriovorus.
abstract: Predatory Bdellovibrio bacteriovorus are natural antimicrobial organisms, killing other bacteria by whole-cell invasion. Self-protection against prey-metabolizing enzymes is important for the evolution of predation. Initial prey entry involves the predator's peptidoglycan DD-endopeptidases, which decrosslink cell walls and prevent wasteful entry by a second predator. Here we identify and characterize a self-protection protein from B. bacteriovorus, Bd3460, which displays an ankyrin-based fold common to intracellular pathogens of eukaryotes. Co-crystal structures reveal Bd3460 complexation of dual targets, binding a conserved epitope of each of the Bd3459 and Bd0816 endopeptidases. Complexation inhibits endopeptidase activity and cell wall decrosslinking in vitro. Self-protection is vital - ΔBd3460 Bdellovibrio deleteriously decrosslink self-peptidoglycan upon invasion, adopt a round morphology, and lose predatory capacity and cellular integrity. Our analysis provides the first mechanistic examination of self-protection in Bdellovibrio, documents protection-multiplicity for products of two different genomic loci, and reveals an important evolutionary adaptation to an invasive predatory bacterial lifestyle.
authors.affiliation: Centre for Genetics and Genomics, School of Biology, Nottingham University, Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK.
authors.forename: Carey
authors.initials: C
authors.lastname: Lambert
authors.affiliation: Institute for Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Ian T
authors.initials: IT
authors.lastname: Cadby
authors.affiliation: Centre for Genetics and Genomics, School of Biology, Nottingham University, Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK.
authors.forename: Rob
authors.initials: R
authors.lastname: Till
authors.affiliation: Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Richardson Road, Newcastle upon Tyne NE2 4AX, UK.
authors.forename: Nhat Khai
authors.initials: NK
authors.lastname: Bui
authors.affiliation: Centre for Genetics and Genomics, School of Biology, Nottingham University, Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK.
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Lerner
authors.affiliation: Institute for Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: William S
authors.initials: WS
authors.lastname: Hughes
authors.affiliation: Institute for Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: David J
authors.initials: DJ
authors.lastname: Lee
authors.affiliation: Institute for Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Luke J
authors.initials: LJ
authors.lastname: Alderwick
authors.affiliation: Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Richardson Road, Newcastle upon Tyne NE2 4AX, UK.
authors.forename: Waldemar
authors.initials: W
authors.lastname: Vollmer
authors.affiliation: Centre for Genetics and Genomics, School of Biology, Nottingham University, Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK.
authors.forename: R Elizabeth
authors.initials: RE
authors.lastname: Sockett
authors.affiliation: Centre for Genetics and Genomics, School of Biology, Nottingham University, Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK.
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Sockett
authors.affiliation: Institute for Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Lovering
mesh_terms: D017487:Ankyrins / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001501:Bdellovibrio / Q000502:physiology*; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D008958:Models, Molecular; D011487:Protein Conformation
chemical_list: D017487:Ankyrins; D001426:Bacterial Proteins