title: Identification of surface proteins in Enterococcus faecalis V583.
abstract: BACKGROUND
  Surface proteins are a key to a deeper understanding of the behaviour of Gram-positive bacteria interacting with the human gastro-intestinal tract. Such proteins contribute to cell wall synthesis and maintenance and are important for interactions between the bacterial cell and the human host. Since they are exposed and may play roles in pathogenicity, surface proteins are interesting targets for drug design.
  
  
  RESULTS
  Using methods based on proteolytic "shaving" of bacterial cells and subsequent mass spectrometry-based protein identification, we have identified surface-located proteins in Enterococcus faecalis V583. In total 69 unique proteins were identified, few of which have been identified and characterized previously. 33 of these proteins are predicted to be cytoplasmic, whereas the other 36 are predicted to have surface locations (31) or to be secreted (5). Lipid-anchored proteins were the most dominant among the identified surface proteins. The seemingly most abundant surface proteins included a membrane protein with a potentially shedded extracellular sulfatase domain that could act on the sulfate groups in mucin and a lipid-anchored fumarate reductase that could contribute to generation of reactive oxygen species.
  
  
  CONCLUSIONS
  The present proteome analysis gives an experimental impression of the protein landscape on the cell surface of the pathogenic bacterium E. faecalis. The 36 identified secreted (5) and surface (31) proteins included several proteins involved in cell wall synthesis, pheromone-regulated processes, and transport of solutes, as well as proteins with unknown function. These proteins stand out as interesting targets for further investigation of the interaction between E. faecalis and its environment.
authors.affiliation: Department of Chemistry, Biotechnology, and Food Science, The Norwegian University of Life Sciences, Ås, Norway.
authors.forename: Liv Anette
authors.initials: LA
authors.lastname: Bøhle
authors.forename: Tahira
authors.initials: T
authors.lastname: Riaz
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Egge-Jacobsen
authors.forename: Morten
authors.initials: M
authors.lastname: Skaugen
authors.forename: Øyvind L
authors.initials: ØL
authors.lastname: Busk
authors.forename: Vincent G H
authors.initials: VG
authors.lastname: Eijsink
authors.forename: Geir
authors.initials: G
authors.lastname: Mathiesen
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D002853:Chromatography, Liquid; D019295:Computational Biology; D004591:Electrophoresis, Polyacrylamide Gel; D013293:Enterococcus faecalis / Q000235:genetics*; D016680:Genome, Bacterial; D008565:Membrane Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D020543:Proteome / Q000235:genetics; D053719:Tandem Mass Spectrometry
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; D020543:Proteome