title: The periodontal pathogen Porphyromonas gingivalis harnesses the chemistry of the mu-oxo bishaem of iron protoporphyrin IX to protect against hydrogen peroxide.
abstract: The major haem component in the black pigment of Porphyromonas gingivalis is the mu-oxo bishaem of iron protoporphyrin IX and formation and cell-surface binding of this haem species is proposed as an extracellular buffer against reactive oxidants [Smalley, J.W. et al. (1998) Biochem. J. 331, 681-685]. P. gingivalis cells grown in the presence of the mu-oxo bishaem were protected against H(2)O(2) compared to control cells grown without it. When added to the growth medium, soluble mu-oxo bishaem inactivated H(2)O(2) and supported cell growth. Cells carrying a surface layer of mu-oxo bishaem were less susceptible to peroxidation by H(2)O(2). Cell-surface haems were slowly destroyed during reaction with H(2)O(2). Binding of mu-oxo bishaem by P. gingivalis may aid survival during neutrophil attack through inactivation of hydrogen peroxide.
authors.affiliation: Unit of Oral Biology, The Edwards Building, Department of Clinical Dental Sciences, The University of Liverpool, Liverpool, UK. josmall@liverpool.ac.uk
authors.forename: J W
authors.initials: JW
authors.lastname: Smalley
authors.forename: A J
authors.initials: AJ
authors.lastname: Birss
authors.forename: J
authors.initials: J
authors.lastname: Silver
mesh_terms: D016866:Bacteroidaceae Infections / Q000382:microbiology; D015169:Colony Count, Microbial; D006418:Heme / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D009195:Peroxidase / Q000378:metabolism; D016966:Porphyromonas gingivalis / Q000254:growth & development / Q000378:metabolism / Q000472:pathogenicity*; D011524:Protoporphyrins / Q000737:chemistry*; D014774:Virulence
chemical_list: D011524:Protoporphyrins; D006418:Heme; D006861:Hydrogen Peroxide; C028025:protoporphyrin IX; D007501:Iron; D009195:Peroxidase