NADPH Inhibits [2Fe-2S] Cluster Protein Transfer from Diabetes Drug Target MitoNEET to an Apo-acceptor Protein
NADPH Inhibits [2Fe-2S] Cluster Protein Transfer from Diabetes Drug Target MitoNEET to an Apo-acceptor Protein
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DOI：
10.1074/jbc.m111.319731
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发表时间：
2012-04-06
影响因子：
4.8
通讯作者：
Jennings, Patricia A.
中科院分区：
文献类型：
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作者：
Zuris, John A.;Ali, Syed S.;Jennings, Patricia A.
MitoNEET （mNT）是最近发现的CDGSH [2Fe-2S]蛋白家族的创始成员，能够将[2Fe-2S]簇转移到载脂蛋白受体蛋白。它是噻唑烷二酮（TZD）类抗糖尿病药物的靶标，其结合调节电子转移和簇转移性质。mNT中的[2Fe-2S]簇在与NADPH结合时不稳定，导致[2Fe-2S]簇在溶液环境中丢失。由于mNT能够将[2Fe-2S]簇转移到载脂蛋白受体蛋白，我们试图确定NADPH结合是否也影响簇转移。我们发现NADPH抑制[2Fe-2S]簇向载脂蛋白受体蛋白的转移，其抑制常数（K-i）为200 μ M，这反映了生理条件下预期的NADPH浓度。此外，我们确定CDGSH结构域中严格保守的簇相互作用残基Asp-84对于nadph依赖性抑制[2Fe-2S]簇转移是必需的。NADPH最关键的细胞功能是维持一个还原等价物池，这是抵抗氧化损伤所必需的。综上所述，我们的研究结果表明，NADPH可以调节细胞中mNT [2Fe-2S]簇的水平，以及蛋白质将[2Fe-2S]簇转移到细胞质或线粒体受体的能力。
MitoNEET (mNT) is the founding member of the recently discovered CDGSH family of [2Fe-2S] proteins capable of [2Fe-2S] cluster transfer to apo-acceptor proteins. It is a target of the thiazolidinedione (TZD) class of anti-diabetes drugs whose binding modulate both electron transfer and cluster transfer properties. The [2Fe-2S] cluster in mNT is destabilized upon binding of NADPH, which leads to loss of the [2Fe-2S] cluster to the solution environment. Because mNT is capable of transferring [2Fe-2S] clusters to apo-acceptor proteins, we sought to determine whether NADPH binding also affects cluster transfer. We show that NADPH inhibits transfer of the [2Fe-2S] cluster to an apo-acceptor protein with an inhibition constant (K-i) of 200 mu M, which reflects that of NADPH concentrations expected under physiological conditions. In addition, we determined that the strictly conserved cluster interacting residue Asp-84 in the CDGSH domain is necessary for the NADPH-dependent inhibition of [2Fe-2S] cluster transfer. The most critical cellular function of NADPH is in the maintenance of a pool of reducing equivalents, which is essential to counteract oxidative damage. Taken together, our findings suggest that NADPH can regulate both mNT [2Fe-2S] cluster levels in the cell as well as the ability of the protein to transfer [2Fe-2S] clusters to cytosolic or mitochondrial acceptors.