Anthrax Research Today is a free monthly online journal that collates and summarizes the latest research about Anthrax, including details on bacillus anthracis, contagiousness, exposure, effects.

Bacillus anthracis IsdG, a heme-degrading monooxygenase.

Skaar EP, Gaspar AH, Schneewind O

Department of Microbiology, University of Chicago, 920 East 58th St. Chicago, IL 60637, USA.

Bacillus anthracis, the causative agent of anthrax, utilizes hemin and hemoglobin for growth in culture, suggesting that these host molecules serve as sources for the nutrient iron during bacterial infection. Bioinformatic analyses of the B. anthracis genome revealed genes with similarity to the iron-regulated surface determinant (isd) system responsible for heme uptake in Staphylococcus aureus. We show that the protein product of one of these genes, isdG, binds hemin in a manner resembling the heme binding of known heme oxygenases. Formation of IsdG:hemin complexes in the presence of a suitable electron donor, e.g., ascorbate or cytochrome P450 reductase, promotes catalytic degradation of hemin to biliverdin with concomitant release of iron. IsdG is required for B. anthracis utilization of hemin as a sole iron source, and it is also necessary for bacterial protection against heme-mediated toxicity. These data suggest that IsdG functions as a heme-degrading monooxygenase in B. anthracis.

Published 23 January 2006 in J Bacteriol, 188(3): 1071-80.
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