The Role of CyaY in Iron Sulfur Cluster Assembly on the E. coli IscU Scaffold Protein
The Role of CyaY in Iron Sulfur Cluster Assembly on the E. coli IscU Scaffold Protein
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DOI：
10.1371/journal.pone.0021992
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发表时间：
2011-07-20
期刊：
影响因子：
3.7
通讯作者：
Pastore, Annalisa
中科院分区：
文献类型：
--
作者：
Iannuzzi, Clara;Adinolfi, Salvatore;Pastore, Annalisa
由于铁硫团簇的形成涉及一个复杂的反应和多组分的体系，因此在理解酶促形成铁硫团簇的机理方面取得了很大的进展。通过利用不同的光谱，我们表征了Frataxin的细菌同源物CyaY对支架蛋白IscU上的簇形成的影响。Frataxin/CyaY是一种高度保守的蛋白质，与人类不可治愈的共济失调有关。以前的研究表明，CyaY是铁硫簇形成的抑制因子。然而，对真核蛋白质的类似研究表明，Frataxin起到了激活剂的作用。我们的研究独立地证实了CyaY减缓了反应，并为CyaY的工作机制提供了新的线索。我们观察到CyaY的存在不改变[2Fe2S](2+)和[4Fe4S](2+)的相对比例，但直接影响酶的活性。
Progress in understanding the mechanism underlying the enzymatic formation of iron-sulfur clusters is difficult since it involves a complex reaction and a multi-component system. By exploiting different spectroscopies, we characterize the effect on the enzymatic kinetics of cluster formation of CyaY, the bacterial ortholog of frataxin, on cluster formation on the scaffold protein IscU. Frataxin/CyaY is a highly conserved protein implicated in an incurable ataxia in humans. Previous studies had suggested a role of CyaY as an inhibitor of iron sulfur cluster formation. Similar studies on the eukaryotic proteins have however suggested for frataxin a role as an activator. Our studies independently confirm that CyaY slows down the reaction and shed new light onto the mechanism by which CyaY works. We observe that the presence of CyaY does not alter the relative ratio between [2Fe2S](2+) and [4Fe4S](2+) but directly affects enzymatic activity.