Issue 10, 2017

Tyr25, Tyr58 and Trp133 of Escherichia coli bacterioferritin transfer electrons between iron in the central cavity and the ferroxidase centre

Abstract

Ferritins are 24meric proteins that overcome problems of toxicity, insolubility and poor bioavailability of iron in all types of cells by storing it in the form of a ferric mineral within their central cavities. In the bacterioferritin (BFR) from Escherichia coli iron mineralization kinetics have been shown to be dependent on an intra-subunit catalytic diiron cofactor site (the ferroxidase centre), three closely located aromatic residues and an inner surface iron site. One of the aromatic residues, Tyr25, is the site of formation of a transient radical, but the roles of the other two residues, Tyr58 and Trp133, are unknown. Here we show that these residues are important for the rates of formation and decay of the Tyr25 radical and decay of a secondary radical observed during Tyr25 radical decay. The data support a mechanism in which these aromatic residues function in electron transfer from the inner surface site to the ferroxidase centre.

Graphical abstract: Tyr25, Tyr58 and Trp133 of Escherichia coli bacterioferritin transfer electrons between iron in the central cavity and the ferroxidase centre

Supplementary files

Article information

Article type
Paper
Submitted
20 Jūn. 2017
Accepted
06 Sept. 2017
First published
06 Sept. 2017
This article is Open Access
Creative Commons BY license

Metallomics, 2017,9, 1421-1428

Spotlight

Advertisements