Department of Geosciences, Princeton University, Princeton, NJ, 08544, USA.
Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA.
Angew Chem Int Ed Engl. 2018 Jan 8;57(2):536-541. doi: 10.1002/anie.201709720. Epub 2017 Dec 8.
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.
微生物利用铁载体来获取环境中必需的铁资源。已知有超过 500 种铁载体，但它们利用一小部分常见的部分来结合铁。棕色固氮菌表达富含铁的氮酶，用它还原 N 。尽管它是一种重要的农业接种剂，但它的铁结合分子的结构仍然未知。在这里，使用小分子发现和生物信息学来研究棕色固氮菌的“螯合组”。该细菌产生弧菌血素和两栖菌素以及一类新型铁载体，即 crochelins。详细的表征表明，最丰富的成员 crochelin A 以六配位方式使用一种新的铁螯合 γ-氨基酸结合铁。本文介绍了 crochelins 的生物合成以及当完整铁载体被导入时铁可能被去除的机制的见解。这项工作扩展了微生物铁载体中铁螯合部分的范围。
