Influence of structural variations on the catalytic properties of recombinant human ferritin

Ferritin is a ubiquitous intracellular iron storage protein consisting of 24 subunits. Storage of iron is its main function and ferritin is able to store up to 4500 iron atoms in a water-soluble, non-toxic, bioavailable form as hydrated ferric oxide mineral core with various amounts of phosphate. Ferritin has a very stable protein scaffold and exhibits remarkable stability towards denaturing agents. The ease with which recombinant ferritin can be produced and purified could turn it into attractive tool for biocatalysis. In the present work, we want to study the importance of the metal-metal distance within the diiron site of ferritin. In conjunction with modern protein engineering strategies, we want to establish the consequences of iron-iron elongation inside the ferroxidase centre on the enzymatic activity. The present results provide more rigorous information than previous on recombinant Human H Ferritin (HuHF) structure. The metal-binding sites in the 3-fold channel (entry route of iron), in the ferroxidase centre (iron oxidation) and on the internal surface of the shell (putative nucleation activity) are described with accuracy and constitute the important points in our understanding of iron incorporation into human ferritin. Moreover our laboratory is interested in mimicking dinuclear active sites of non-haem diiron proteins using as support, the stable human H ferritin. The ferroxidase mutants were in this purpose tested for an oxidase activity towards an organic compound.Doctorat en sciences (sciences chimiques) (CHIM 3)--UCL, 200