title: Species specificity, surface exposure, protein expression, immunogenicity, and participation in biofilm formation of Porphyromonas gingivalis HmuY.
abstract: BACKGROUND
  Porphyromonas gingivalis is a major etiological agent of chronic periodontitis. The aim of this study was to examine the species specificity, surface exposure, protein expression, immunogenicity, and participation in biofilm formation of the P. gingivalis heme-binding protein HmuY.
  
  
  RESULTS
  HmuY is a unique protein of P. gingivalis since only low amino-acid sequence homology has been found to proteins encoded in other species. It is exposed on the cell surface and highly abundant in the outer membrane of the cell, in outer-membrane vesicles, and is released into culture medium in a soluble form. The protein is produced constitutively at low levels in bacteria grown under high-iron/heme conditions and at higher levels in bacteria growing under the low-iron/heme conditions typical of dental plaque. HmuY is immunogenic and elicits high IgG antibody titers in rabbits. It is also engaged in homotypic biofilm formation by P. gingivalis. Anti-HmuY antibodies exhibit inhibitory activity against P. gingivalis growth and biofilm formation.
  
  
  CONCLUSIONS
  Here it is demonstrated that HmuY may play a significant role not only in heme acquisition, but also in biofilm accumulation on abiotic surfaces. The data also suggest that HmuY, as a surface-exposed protein, would be available for recognition by the immune response during chronic periodontitis and the production of anti-HmuY antibodies may inhibit biofilm formation.
authors.affiliation: Laboratory of Biochemistry, Faculty of Biotechnology, University of Wroclaw, Tamka 2, 50-137 Wroclaw, Poland. Teresa.Olczak@biotech.uni.wroc.pl
authors.forename: Teresa
authors.initials: T
authors.lastname: Olczak
authors.forename: Halina
authors.initials: H
authors.lastname: Wójtowicz
authors.forename: Justyna
authors.initials: J
authors.lastname: Ciuraszkiewicz
authors.forename: Mariusz
authors.initials: M
authors.lastname: Olczak
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood / Q000276:immunology; D001426:Bacterial Proteins / Q000032:analysis / Q000276:immunology* / Q000502:physiology*; D018441:Biofilms / Q000254:growth & development*; D002352:Carrier Proteins / Q000032:analysis / Q000276:immunology* / Q000502:physiology*; D002462:Cell Membrane / Q000737:chemistry; D000081062:Heme-Binding Proteins; D006420:Hemeproteins / Q000032:analysis / Q000276:immunology* / Q000502:physiology*; D008565:Membrane Proteins / Q000032:analysis / Q000276:immunology / Q000502:physiology; D016966:Porphyromonas gingivalis / Q000737:chemistry / Q000502:physiology*; D011817:Rabbits; D022142:Secretory Vesicles / Q000737:chemistry
chemical_list: D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D002352:Carrier Proteins; D000081062:Heme-Binding Proteins; D006420:Hemeproteins; D008565:Membrane Proteins