Spectroscopic, EPR and crystallographic studies of demetallation of haemin by mammalian apoferritins
(2002)
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- Authors
- Supervisors
- Chrichton, Robert
- Abstract
- (en) An essential difference between eucaryote ferritins and bacterioferritins is that the latter contain naturally, in vivo haem as Fe-protoporphyrin IX. This haem is located in a hydrophobic pocket along the 2-fold symmetry axes and is liganded by 2 Met 52. However, by using another method of ferritin purification, it has been possible to isolate a cofactor in horse spleen apoferritin which presents the spectroscopic characteristics of a protoporphyrin IX (PPIX). Studies of haemin (Fe(III)-PPIX) incorporation into horse spleen apoferritin were also carried out. By crystallography, Sn(II)-PPIX, Fe(III)-PPIX were found in a hydrophobic pocket along the 2-fold symmetry axes as in bacterioferritins but they were demetallated. Spectroscopic studies of demetallation of haemin by horse spleen apoferritin were carried out and a mechanism of demetallation of haemin by L-chain apoferritins was proposed: 4 Glu residues (Glu 53, 56, 57, 60) situated at the entrance of the hydrophobic pocket and acidic conditions seem to be involved
- Affiliations
Citations
Carette, N. (2002). Spectroscopic, EPR and crystallographic studies of demetallation of haemin by mammalian apoferritins. https://hdl.handle.net/2078.5/124238