Human Mitochondrial Ferredoxin 1 (FDX1) and Ferredoxin 2 (FDX2) Both Bind Cysteine Desulfurase and Donate Electrons for Iron-Sulfur Cluster Biosynthesis.
Human Mitochondrial Ferredoxin 1 (FDX1) and Ferredoxin 2 (FDX2) Both Bind Cysteine Desulfurase and Donate Electrons for Iron-Sulfur Cluster Biosynthesis.
复制标题
人线粒体铁蛋白1（FDX1）和铁氧还蛋白2（FDX2）都结合半胱氨酸脱硫酶，并捐赠电子以用于铁硫簇生物合成。
DOI：
10.1021/acs.biochem.6b00447
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发表时间：
2017-01-24
期刊：
影响因子：
2.9
通讯作者：
Markley JL
中科院分区：
文献类型：
--
作者：
Cai K;Tonelli M;Frederick RO;Markley JL
铁还原蛋白作为电子供体在铁硫（Fe-S）簇生物合成中起着重要的作用。人线粒体基质中存在两种铁氧化还蛋白，即人线粒体铁氧化还蛋白1 （FDX1）和人线粒体铁氧化还蛋白2 （FDX2）。关于它们各自在线粒体铁硫团簇生物发生中的作用，已经报道了相互矛盾的结果。我们在此报告了这两种铁还原蛋白与线粒体铁硫簇组装中涉及的其他蛋白质相互作用的生物物理研究。核磁共振波谱结果表明，FDX1和FDX2（还原和氧化状态）都与负责簇组装的蛋白质复合物相互作用，该复合物含有半胱氨酸脱硫酶（NFS1）、ISD11（也称为LYRM4）和酰基载体蛋白（Acp）。在所有情况下，靠近Fe-S簇的铁氧还蛋白残基都参与了与该复合物的相互作用。等温滴定量热法结果表明，FDX2比FDX1与半胱氨酸脱硫酶复合物结合更紧密。当加入l-半胱氨酸时，每种铁氧还蛋白的还原形式在半胱氨酸脱硫酶复合物存在下被氧化，导致其转化为l-丙氨酸并生成硫化物。在体外反应中，发现每个铁氧还蛋白的还原形式支持Fe-S簇在ISCU上的组装；与FDX1相比，FDX2的聚类速度更快。综上所述，这些结果表明FDX1和FDX2都可以在体外Fe-S簇组装中发挥作用。
Ferredoxins play an important role as an electron donor in iron–sulfur (Fe–S) cluster biosynthesis. Two ferredoxins, human mitochondrial ferredoxin 1 (FDX1) and human mitochondrial ferredoxin 2 (FDX2), are present in the matrix of human mitochondria. Conflicting results have been reported regarding their respective function in mitochondrial iron–sulfur cluster biogenesis. We report here biophysical studies of the interaction of these two ferredoxins with other proteins involved in mitochondrial iron–sulfur cluster assembly. Results from nuclear magnetic resonance spectroscopy show that both FDX1 and FDX2 (in both their reduced and oxidized states) interact with the protein complex responsible for cluster assembly, which contains cysteine desulfurase (NFS1), ISD11 (also known as LYRM4), and acyl carrier protein (Acp). In all cases, ferredoxin residues close to the Fe–S cluster are involved in the interaction with this complex. Isothermal titration calorimetry results showed that FDX2 binds more tightly to the cysteine desulfurase complex than FDX1 does. The reduced form of each ferredoxin became oxidized in the presence of the cysteine desulfurase complex when l-cysteine was added, leading to its conversion to l-alanine and the generation of sulfide. In an in vitro reaction, the reduced form of each ferredoxin was found to support Fe–S cluster assembly on ISCU; the rate of cluster assembly was faster with FDX2 than with FDX1. Taken together, these results show that both FDX1 and FDX2 can function in Fe–S cluster assembly in vitro.