Kinetic analysis of the oxidative conversion of the [4Fe-4S]2+ cluster of FNR to a [2Fe-2S]2+ Cluster.
Kinetic analysis of the oxidative conversion of the [4Fe-4S]2+ cluster of FNR to a [2Fe-2S]2+ Cluster.
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FNR 的 [4Fe-4S]2 簇氧化转化为 [2Fe-2S]2 簇的动力学分析。
DOI：
10.1128/jb.186.23.8018-8025.2004
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
Kiley,PatriciaJ
中科院分区：
文献类型：
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作者：
Sutton,VictoriaR;Mettert,ErinL;Beinert,Helmut;Kiley,PatriciaJ
FNR 感知和响应细胞 O2 水平的能力取决于其 [4Fe-4S]2+ 簇。在 O2 存在的情况下，[4Fe-4S]2+ 簇转化为 [2Fe-2S]2+ 簇，从而使 FNR 作为转录调节因子失活。在这项研究中，我们证明 O2 与 [4Fe-4S]2+ 团簇的反应释放了~2 个 Fe2+ 离子。然后使用 Fe2+ 释放作为反应进程的测定，以研究体外 [4Fe-4S]2+ 到 [2Fe-2S]2+ 簇转化的速率。我们还发现，与 DNA 结合形式相比，溶液中游离 FNR 的 O2 诱导簇转化率没有可检测到的差异。此外，通过测量细胞暴露于 O2 后 FNR 转录调节丧失的速率来监测体内 FNR 失活的速率；体外和体内转化率的比较表明，O2 诱导的簇转化足以解释细胞中 FNR 的失活。还比较了在有氧和厌氧条件下生长的细胞的 FNR 蛋白水平。
The ability of FNR to sense and respond to cellular O2levels depends on its [4Fe-4S]2+cluster. In the presence of O2, the [4Fe-4S]2+cluster is converted to a [2Fe-2S]2+cluster, which inactivates FNR as a transcriptional regulator. In this study, we demonstrate that ∼2 Fe2+ions are released from the reaction of O2with the [4Fe-4S]2+cluster. Fe2+release was then used as an assay of reaction progress to investigate the rate of [4Fe-4S]2+to [2Fe-2S]2+cluster conversion in vitro. We also found that there was no detectable difference in the rate of O2-induced cluster conversion for FNR free in solution compared to its DNA-bound form. In addition, the rate of FNR inactivation was monitored in vivo by measuring the rate at which transcriptional regulation by FNR is lost upon the exposure of cells to O2; a comparison of the in vitro and in vivo rates of conversion suggests that O2-induced cluster conversion is sufficient to explain FNR inactivation in cells. FNR protein levels were also compared for cells grown under aerobic and anaerobic conditions.