Monothiol glutaredoxins function in storing and transporting [Fe2S2] clusters assembled on IscU scaffold proteins.
Monothiol glutaredoxins function in storing and transporting [Fe2S2] clusters assembled on IscU scaffold proteins.
复制标题
单硫醇谷氧还蛋白在储存和运输 IscU 支架蛋白上组装的 [Fe2S2] 簇方面发挥作用。
DOI：
10.1021/ja306061x
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发表时间：
2012
影响因子：
15
通讯作者：
Johnson,MichaelK
中科院分区：
文献类型：
--
作者：
Shakamuri,Priyanka;Zhang,Bo;Johnson,MichaelK
在铁硫簇组装的细菌ISC系统中，IscU充当主要支架蛋白，分子辅伴侣HscA和HscB特异性地与IscU相互作用以促进ATP驱动的簇转移。本工作将棕色固氮菌[Fe_2S_2]~（2+）簇结合的IscU簇转移到A. vinelandii，通过圆二色光谱，在不存在和存在的HscA/HscB/Mg-ATP的情况下进行监测。结果表明，在共分子伴侣和Mg-ATP的存在下，[Fe2S2] 2+簇转移速率提高了700倍，在23 ° C下产生20 000 M-1min-1的二级速率常数。因此，HscA和HscB是从IscU到Grx5的有效ATP依赖性[Fe2S2] 2+簇转移所必需的。这些结果支持了单硫醇Grx在储存和运输[Fe2S2] 2+簇组装在IscU上的作用，并说明了在没有专用HscA/HscB共分子伴侣系统的情况下，涉及[Fe2S2]-IscU的体外簇转移研究的局限性。
In the bacterial ISC system for iron–sulfur cluster assembly, IscU acts as a primary scaffold protein, and the molecular co-chaperones HscA and HscB specifically interact with IscU to facilitate ATP-driven cluster transfer. In this work, cluster transfer fromAzotobacter vinelandii[Fe2S2]2+cluster-bound IscU to apo-Grx5, a general purpose monothiol glutaredoxin inA. vinelandii, was monitored by circular dichroism spectroscopy, in the absence and in the presence of HscA/HscB/Mg-ATP. The results indicate a 700-fold enhancement in the rate of [Fe2S2]2+cluster transfer in the presence of the co-chaperones and Mg-ATP, yielding a second-order rate constant of 20 000 M–1min–1at 23 °C. Thus, HscA and HscB are required for efficient ATP-dependent [Fe2S2]2+cluster transfer from IscU to Grx5. The results support a role for monothiol Grx’s in storing and transporting [Fe2S2]2+clusters assembled on IscU and illustrate the limitations of interpretingin vitrocluster transfer studies involving [Fe2S2]-IscU in the absence of the dedicated HscA/HscB co-chaperone system.