Crochelins: Siderophores with an Unprecedented Iron-Chelating Moiety from the Nitrogen-Fixing Bacterium Azotobacter chroococcum
Crochelins: Siderophores with an Unprecedented Iron-Chelating Moiety from the Nitrogen-Fixing Bacterium Azotobacter chroococcum
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DOI：
10.1002/anie.201709720
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发表时间：
2018-01-08
影响因子：
16.6
通讯作者：
Seyedsayamdost, Mohammad R.
中科院分区：
文献类型：
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作者：
Baars, Oliver;Zhang, Xinning;Seyedsayamdost, Mohammad R.
微生物利用铁载体获取环境中必需的铁资源。已知的铁载体超过500种，但它们利用一小部分常见的结构单元来结合铁。褐球固氮菌表达富含铁的固氮酶，借此还原N₂。尽管它是一种重要的农业接种剂，但其铁结合分子的结构仍然未知。在此，利用小分子发现和生物信息学方法对褐球固氮菌的“螯合物组”进行了研究。该细菌产生弧菌铁蛋白和两栖菌素以及一类新的铁载体家族——克罗切林。详细的特性分析表明，最丰富的成员克罗切林A使用一种新的铁螯合γ -氨基酸以六齿方式结合铁。文中还介绍了对克罗切林生物合成的见解以及在全铁载体输入时铁可能被去除的机制。这项工作扩充了微生物铁载体中铁螯合结构单元的种类。
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-2. 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 g-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.