Crochelins: Siderophores with an Unprecedented Iron-Chelating Moiety from the Nitrogen-Fixing Bacterium Azotobacter chroococcum.

Publication Year
2018

Type

Journal Article
Abstract

Microbes use siderophores to access essential iron resources in the environment. Over 500 siderophores are known, but they utilize a small set of common moieties to bind iron. Azotobacter chroococcum expresses iron-rich nitrogenases, with which it reduces N . Though an important agricultural inoculant, the structures of its iron-binding molecules remain unknown. Here, the "chelome" of A. chroococcum is examined using small molecule discovery and bioinformatics. The bacterium produces vibrioferrin and amphibactins as well as a novel family of siderophores, the crochelins. Detailed characterization shows that the most abundant member, crochelin A, binds iron in a hexadentate fashion using a new iron-chelating γ-amino acid. Insights into the biosynthesis of crochelins and the mechanism by which iron may be removed upon import of the holo-siderophore are presented. This work expands the repertoire of iron-chelating moieties in microbial siderophores.

Journal
Angew Chem Int Ed Engl
Volume
57
Issue
2
Pages
536-541
Date Published
2018 Jan 08
ISSN Number
1521-3773
Alternate Journal
Angew Chem Int Ed Engl
PMID
29134779