Haemin binding as a factor in the virulence of Porphyromonas gingivalis

John W. Smalley*, Andrew J. Birss, Ailsa S. McKee, Phillip Marsh

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


Haemin (iron protoporphyrin IX) is an essential growth factor for the periodontal pathogen, Porphyromonas gingivalis. Iron protoporphyrin IX (IPP IX) binding to the avirulent P. gingivalis beige variant (W50/BE1) and the black-pigmenting parent wild-type strain W50 was quantified. W50/BE1 grown in a chemostat under haemin excess-bound IPP IX under both oxidising and reducing conditions but with both lower capacity and avidity than either the haemin-limited- and haemin-excess-grown parent strain W50. Rosenthal plots for W50/BE1 indicated cooperative binding. W50/BE1 cells expressed a 32 kDa outer membrane haemin-binding protein when grown under conditions of haemin excess, and this strain might serve as a useful source from which to isolate this protein. The reduced IPP IX binding ability of W50/BE1 may be the rate-limiting factor for haem uptake and explain the reduced virulence and slower rate of pigmentation of this strain.

Original languageEnglish
Pages (from-to)65-70
Number of pages6
JournalFEMS Microbiology Letters
Issue number1
Publication statusPublished - 15 Jul 1996


  • Binding
  • Haemin
  • Porphyromonas gingivalis
  • Virulence


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