In vivo heme scavenging by Staphylococcus aureus IsdC and IsdE proteins

John Mack, Christie Vermeiren, David E. Heinrichs, Martin J. Stillman

Research output: Contribution to journalArticlepeer-review

45 Citations (Scopus)


We report the first characterization of the in vivo porphyrin scavenging abilities of two components of a newly discovered heme scavenging system involving iron-regulated surface determinant (Isd) proteins. These proteins are present within the cell envelope of the Gram-positive human pathogen Staphylococcus aureus. IsdC and IsdE, when expressed heterologously in Escherichia coli, efficiently scavenged intracellular heme and resulted in de novo heme synthesis in excess of 100-fold above background. Magnetic circular dichroism analyses showed that the heme-binding properties of the two proteins differ significantly from one another. IsdC bound almost exclusively free-base protoporphyrin IX, whereas the IsdE protein was associated with low spin Fe(III) and Fe(II) heme. These properties provide important insight into the possible mechanisms of iron scavenging from bound heme by Isd proteins.

Original languageEnglish
Pages (from-to)781-788
Number of pages8
JournalBiochemical and biophysical research communications
Issue number3
Publication statusPublished - 2004 Jul 30
Externally publishedYes


  • Gram-positive human pathogen Staphylococcus aureus
  • Heme binding
  • Iron scavenging
  • Iron-regulated surface determinant proteins
  • Magnetic circular dichroism

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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