Spectroscopic definition of the ferroxidase site in M ferritin: comparison of binuclear substrate vs cofactor active sites.

ABSTRACT: Maxi ferritins, 24 subunit protein nanocages, are essential in humans, plants, bacteria, and other animals for the concentration and storage of iron as hydrated ferric oxide, while minimizing free radical generation or use by pathogens. Formation of the precursors to these ferric oxides is catalyzed at a nonheme biferrous substrate site, which has some parallels with the cofactor sites in other biferrous enzymes. A combination of circular dichroism (CD), magnetic circular dichroism (MCD), and variable-temperature, variable-field MCD (VTVH MCD) has been used to probe Fe(II) binding to the substrate active site in frog M ferritin. These data determined that the active site within each subunit consists of two inequivalent five-coordinate (5C) ferrous centers that are weakly antiferromagnetica

SUBMITTER: Schwartz JK 

PROVIDER: S-EPMC2531225 | biostudies-literature | 2008 Jul

REPOSITORIES: biostudies-literature