Article

Discovery and characterization of a unique mycobacterial heme acquisition system.

Departments of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.81). 03/2011; 108(12):5051-6. DOI: 10.1073/pnas.1009516108
Source: PubMed

ABSTRACT Mycobacterium tuberculosis must import iron from its host for survival, and its siderophore-dependent iron acquisition pathways are well established. Here we demonstrate a newly characterized pathway, whereby M. tuberculosis can use free heme and heme from hemoglobin as an iron source. Significantly, we identified the genomic region, Rv0202c-Rv0207c, responsible for the passage of heme iron across the mycobacterial membrane. Key players of this heme uptake system were characterized including a secreted protein and two transmembrane proteins, all three specific to mycobacteria. Furthermore, the crystal structure of the key heme carrier protein Rv0203 was found to have a unique fold. The discovery of a unique mycobacterial heme acquisition pathway opens new avenues of exploration into mycobacterial therapeutics.

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Christine Crosby