title: Fate of predator and prey proteins during growth of Bdellovibrio bacteriovorus on Escherichia coli and Pseudomonas syringae prey.
abstract: A two-dimensional electrophoretic analysis of protein distribution followed by identification of selected proteins by mass spectrometry was performed on fresh bdellovibrio cultures containing attack phase cells of the predatory bacterium Bdellovibrio bacteriovorus strain 109J-1 and the remains of an Escherichia coli or a Pseudomonas syringae pv. tomato prey. Cleavage of the peptidoglycan-associated outer membrane proteins (OMPs) OmpA in E. coli and OprF in P. syringae occurred in both prey. The tryptic peptides obtained from the cleavage products of OmpA and OprF were all located within the 19-kDa pronase-resistant N-terminal parts of the corresponding proteins. The predator cell fraction was separated from the prey ghosts in fresh bdellovibrio cultures by centrifugation on a Percoll-sucrose cushion. Proteins from each fraction were separated by two-dimensional electrophoresis and identified by mass spectrometric analysis. As no prey OMP could be detected in the predator cell fraction, it was concluded that prey OMPs are not transferred to the predator, as had been suggested previously. However, a protein from the predator was found bound to ghost cell envelopes. This protein may correspond to a protein earlier suggested to be associated with the prey outer or cytoplasmic membranes. Along with recently described polypeptides from B. bacteriovorus strains 100 and 114, it forms a new family of putative outer membrane proteins.
authors.affiliation: Department of Plant Pathology and Microbiology, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, P.O. Box 12, 76100 Rehovot, Israel.
authors.forename: Gilli
authors.initials: G
authors.lastname: Barel
authors.forename: Alexandra
authors.initials: A
authors.lastname: Sirota
authors.forename: Hanne
authors.initials: H
authors.lastname: Volpin
authors.forename: Edouard
authors.initials: E
authors.lastname: Jurkevitch
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000032:analysis*; D001483:Base Sequence; D001501:Bdellovibrio / Q000737:chemistry / Q000254:growth & development*; D015180:Electrophoresis, Gel, Two-Dimensional; D004926:Escherichia coli / Q000502:physiology*; D008969:Molecular Sequence Data; D044224:Pseudomonas syringae / Q000502:physiology*
chemical_list: D001425:Bacterial Outer Membrane Proteins