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

TitleCrochelins: Siderophores with an Unprecedented Iron-Chelating Moiety from the Nitrogen-Fixing Bacterium Azotobacter chroococcum.
Publication TypeJournal Article
Year of Publication2018
AuthorsBaars, O, Zhang, X, Gibson, MI, Stone, AT, Morel, FMM, Seyedsayamdost, MR
JournalAngew Chem Int Ed Engl
Volume57
Issue2
Pagination536-541
Date Published2018 Jan 08
ISSN1521-3773
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.

DOI10.1002/anie.201709720
Alternate JournalAngew. Chem. Int. Ed. Engl.
PubMed ID29134779