title: Iron oxidation and hydrolysis reactions of a novel ferritin from Listeria innocua.
abstract: Iron deposition in the unusual 12-subunit ferritin from thebacterium Listeria innocua proceeds in three phases: a rapidfirst phase in which Fe(2+) binds to the apoprotein, P(Z) of charge Z, according to the postulatedreaction 2Fe(2+)+P(Z)-->[Fe(2)-P](Z+2)+2H(+), where[Fe(2)-P](Z+2) represents adinuclear iron(II) complex formed at each of the 12 ferroxidase centresof the protein; a second phase corresponding to oxidation of thisputative complex, i.e. [Fe(2)-P](Z+2)+1/2 O(2)-->[Fe(2)O-P](Z)+2H(+);and a third phase of iron(II) oxidation/mineralization, i.e. 4Fe(2+)+O(2)+8H(2)O-->8FeOOH((s))+8H(+) [where FeOOH((s)) represents the hydrous ferric oxidemineral that precipitates from the solution], which occurs when iron isadded in excess of 24Fe(2+)/protein. In contrast with otherferritins, the ferroxidation reaction in L. innocua ferritinproceeds more slowly than the oxidation/mineralization reaction. Wateris the final product of dioxygen reduction in the 12-subunit L.innocua ferritin (the present work) and in the 24-subunit Escherichia coli bacterioferritin, whereas H(2)O(2) is produced in 24-subunit mammalian ferritins. Possible reasonsfor this difference are discussed.
authors.affiliation: Department of Chemistry, Parsons Hall, University of New Hampshire, Durham, NH 03824, USA.
authors.forename: X
authors.initials: X
authors.lastname: Yang
authors.forename: E
authors.initials: E
authors.lastname: Chiancone
authors.forename: S
authors.initials: S
authors.lastname: Stefanini
authors.forename: A
authors.initials: A
authors.lastname: Ilari
authors.forename: N D
authors.initials: ND
authors.lastname: Chasteen
mesh_terms: D005293:Ferritins / Q000737:chemistry*; D006868:Hydrolysis; D007501:Iron / Q000737:chemistry*; D008087:Listeria / Q000737:chemistry*; D010084:Oxidation-Reduction
chemical_list: D005293:Ferritins; D007501:Iron