Biology Reference
In-Depth Information
Chapter 3
Mycobacterial Iron Acquisition Mechanisms
B. Rowe Byers
Abstract In both pathogenic and saprophytic mycobacteria, many of the genes
and systems required for high affinity iron acquisition have been identified, includ-
ing siderophore production, uptake of ferric-siderophores, production of iron
storage proteins, and uptake of heme. Production and function of iron uptake
mechanisms is controlled by a regulatory protein. Possible low affinity acquisition
through multiple function porins also has been described. In pathogenic mycobac-
teria, most of the high affinity systems appear necessary for maintenance of an
infection. Greater definition of the functions of both the identified genes and genes
yet to be discovered will refine our understanding of mycobacterial iron acquisi-
tion and the interplay between components of the iron systems.
Keywords  Iron • Siderophores • Mycobactin • Carboxymycobactin • Exochelin 
• Mycobacterial heme utilization • Ferritin • Bacterioferritin • Continuous culture 
of mycobacteria
3.1 The Need for Siderophores in Iron Acquisition
Just as iron is essential in the metabolism of almost all modern biological cells,
so the metal was crucial in the chemical reactions that created life. Assuming
that life did not arrive on Earth by seeding from an extraterrestrial source, it has
been proposed that the energy driving the primordial system was provided by the
reaction converting ferrous ions and hydrogen sulfide to iron pyrite [ 1 ]. This is
thought to have occurred in the upwelling heated water at the deep sea juncture
of tectonic plates. The non-protein iron sulfur clusters that formed at the edges of
B. R. Byers ( * )
The University of Mississippi Medical Center, Jackson, MS, USA
e-mail: rowebyers@comcast.net
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