Reaction of O₂ with a diiron protein generates a mixed-valent Fe²⁺/Fe³⁺ center and peroxide.

ABSTRACT: The gene encoding the cyanobacterial ferritin SynFtn is up-regulated in response to copper stress. Here, we show that, while SynFtn does not interact directly with copper, it is highly unusual in several ways. First, its catalytic diiron ferroxidase center is unlike those of all other characterized prokaryotic ferritins and instead resembles an animal H-chain ferritin center. Second, as demonstrated by kinetic, spectroscopic, and high-resolution X-ray crystallographic data, reaction of O₂ with the di-Fe²⁺ center results in a direct, one-electron oxidation to a mixed-valent Fe²⁺/Fe³⁺ form. Iron-O₂ chemistry of this type is currently unknown among the growing family of proteins that bind a diiron site within a four α-helica

SUBMITTER: Bradley JM 

PROVIDER: S-EPMC6369749 | biostudies-literature | 2019 Feb

REPOSITORIES: biostudies-literature