Identification and Characterization of the Staphylococcus aureus Gene Cluster Coding for Staphyloferrin A
Identification and Characterization of the Staphylococcus aureus Gene Cluster Coding for Staphyloferrin A
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DOI：
10.1021/bi801844c
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发表时间：
2009-02-10
期刊：
影响因子：
2.9
通讯作者：
Balibar, Carl J.
中科院分区：
文献类型：
--
作者：
Cotton, Jennifer L.;Tao, Jianshi;Balibar, Carl J.
铁载体是细菌在铁限制环境中生长的关键毒力因子。已知革兰氏阳性病原体金黄色葡萄球菌产生四种铁载体，其遗传和/或结构数据未知。在这里，我们的特点是基因簇负责生产流行的铁载体葡萄铁蛋白A。除了在异源宿主大肠杆菌中表达该簇，从而赋予合成铁载体的能力之外，我们通过表达和纯化途径中的两种关键酶来体外重建葡萄球菌铁蛋白A的生物合成。与其他聚羧酸铁载体一样，葡萄铁蛋白A是使用最近描述的非核糖体肽合成酶独立的铁载体（NIS）生物合成途径生物合成的。两个NIS合成酶在逐步有序的过程中将两个柠檬酸分子缩合为D-鸟氨酸，其中SfnaD使用δ-胺作为亲核试剂形成第一个酰胺，然后SfnaB使用α-胺完成葡萄球菌铁蛋白A的合成。
Siderophores are key virulence factors that allow bacteria to grow in iron-restricted environments. The Gram-positive pathogen Staphylococcus aureus is known to produce four siderophores for which genetic and/or structural data are unknown. Here we characterize the gene cluster responsible for producing the prevalent siderophore staphyloferrin A. In addition to expressing the cluster in the heterologous host Escherichia coli, which confers the ability to synthesize the siderophore, we reconstituted staphyloferrin A biosynthesis in vitro by expressing and purifying two key enzymes in the pathway. As with other polycarboxylate siderophores, staphyloferrin A is biosynthesized using the recently described nonribosomal peptide synthetase independent siderophore (NIS) biosynthetic pathway. Two NIS synthetases condense two molecules of citric acid to D-ornithine in a stepwise ordered process with SfnaD using the delta-amine as a nucleophile to form the first amide followed by SfnaB utilizing the alpha-amine to complete staphyloferrin A synthesis.