Iron acquisition with the natural siderophore enantiomers pyochelin and enantio-pyochelin in Pseudomonas species
Iron acquisition with the natural siderophore enantiomers pyochelin and enantio-pyochelin in Pseudomonas species
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DOI：
10.1007/s10534-010-9399-9
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发表时间：
2011-06
期刊：
影响因子：
3.5
通讯作者：
Z. Youard;N. Wenner;C. Reimmann
中科院分区：
文献类型：
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作者：
Z. Youard;N. Wenner;C. Reimmann
细菌铁载体绿脓菌螯铁蛋白由水杨酸盐和两个半胱氨酸衍生的杂环组成，其中第二个在生物合成过程中通过还原和N-甲基化修饰。在铜绿假单胞菌中，第一个半胱氨酸残基在噻唑啉环形成过程中转化为D-异构体，而第二个半胱氨酸保持L-构型。荧光假单胞菌对映体绿脓菌螯铁蛋白的立体化学结构相反，第一个环来自L-半胱氨酸，第二个环来自D-半胱氨酸。这两种铁载体在铁限制期间促进生产生物体的生长，并通过激活转录AraC型调节剂PchR诱导其生物合成基因的表达。然而，无论是铁载体的功能，或作为转录诱导剂在其他物种，这表明这两个过程是高度立体特异性。绿脓菌螯铁蛋白/对映体绿脓菌螯铁蛋白介导的铁摄取的立体特异性在两个水平上得到确保：（i）通过外膜铁载体受体和（ii）通过胞质PchR调节剂。
The bacterial siderophore pyochelin is composed of salicylate and two cysteine-derived heterocycles, the second of which is modified by reduction and N-methylation during biosynthesis. InPseudomonas aeruginosa,the first cysteine residue is converted to its D-isoform during thiazoline ring formation, whereas the second cysteine remains in its L-configuration. Stereochemistry is opposite in thePseudomonas fluorescenssiderophore enantio-pyochelin, in which the first ring originates from L-cysteine and the second ring from D-cysteine. Both siderophores promote growth of the producer organism during iron limitation and induce the expression of their biosynthesis genes by activating the transcriptional AraC-type regulator PchR. However, neither siderophore is functional as an iron carrier or as a transcriptional inducer in the other species, demonstrating that both processes are highly stereospecific. Stereospecificity of pyochelin/enantio-pyochelin-mediated iron uptake is ensured at two levels: (i) by the outer membrane siderophore receptors and (ii) by the cytosolic PchR regulators.