Following the appearance of oxygen, which led to the precipitation of iron hydroxides that had become ferric and therefore insoluble, microorganisms developed an efficient strategy for acquiring the iron they needed to grow. This evolutionary response involves : the biosynthesis of small molecules (siderophores) which, when externalized, are capable of solubilizing ferric iron from the environment; a system of membrane proteins that receive ferrisiderophores; and reductases that deliver ferrous iron, enabling the metal to be utilized by iron apoproteins.
The design and study of synthetic siderophores serves a triple purpose:
- forging chemical tools to better understand iron metabolism (many "black boxes" remain to this day) ;
- develop iron-chelating drugs to treat iron overload (hemochromatosis), a lethal disease affecting millions of people ;
- develop ferric complexes adapted to the nutrition of marine bacteria (which play a fundamental role in the transformation ofCO2 into oxygen) that wither in the event of iron deficiency, or to plant nutrition, particularly in calcareous soils.
This presentation reported on the work of a chemistry laboratory into the synthesis of new iron chelators, physico-chemical studies of complexation (thermodynamics and kinetics) and biological applications, including the development of molecular chelators as well as amphiphilic systems, mimicking the siderophores of marine bacteria capable of self-assembling into vesicles.
