A [3Fe-4S] cluster is required for tRNA thiolation in archaea and eukaryotes
A [3Fe-4S] cluster is required for tRNA thiolation in archaea and eukaryotes
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DOI：
10.1073/pnas.1615732113
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发表时间：
2016-11-08
影响因子：
11.1
通讯作者：
Soll, Dieter
中科院分区：
文献类型：
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作者：
Liu, Yuchen;Vinyard, David J.;Soll, Dieter
转移RNA中的含硫核苷(TRNAs)存在于生命的三个结构域中，它们对准确高效的翻译具有关键作用，如tRNA结构稳定和正确的密码子识别。TRNA修饰酶ThiI(在细菌和古生物中)和Ncs6(在古生物和真核细胞胞浆中)分别催化4-硫脲(S(4)U)和2-硫脲(S(2)U)的形成。ThiI同系物被认为是通过半胱氨酸过硫化物酶加合物来转移硫的，而NCS6的反应机理尚不清楚。在这里，我们证明了来自甲烷球菌maripaludis的ThiI包含一个[3Fe-4S]簇，这是其tRNA硫化活性所必需的。此外，古生菌和真核生物的Ncs6同源物以及在产甲烷菌中催化Sep-tRNA转化为Cys-tRNA的磷酸化Sep-tRNA(Sep-tRNA)：Cys-tRNA合成酶(SepCysS)也具有与产甲烷古生菌ThiI类似的[3Fe-4S]簇。这些结果表明，古细菌和真核细胞溶质中不同的tRNA硫化过程具有共同的机制，依赖于[3Fe-4S]簇进行硫转移。
The sulfur-containing nucleosides in transfer RNA (tRNAs) are present in all three domains of life; they have critical functions for accurate and efficient translation, such as tRNA structure stabilization and proper codon recognition. The tRNA modification enzymes ThiI (in bacteria and archaea) and Ncs6 (in archaea and eukaryotic cytosols) catalyze the formation of 4-thiouridine (s(4)U) and 2-thiouridine (s(2)U), respectively. The ThiI homologs were proposed to transfer sulfur via cysteine persulfide enzyme adducts, whereas the reaction mechanism of Ncs6 remains unknown. Here we show that ThiI from the archaeon Methanococcus maripaludis contains a [3Fe-4S] cluster that is essential for its tRNA thiolation activity. Furthermore, the archaeal and eukaryotic Ncs6 homologs as well as phosphoseryl-tRNA (Sep-tRNA): Cys-tRNA synthase (SepCysS), which catalyzes the Sep-tRNA to Cys-tRNA conversion in methanogens, also possess a [3Fe-4S] cluster similar to the methanogenic archaeal ThiI. These results suggest that the diverse tRNA thiolation processes in archaea and eukaryotic cytosols share a common mechanism dependent on a [3Fe-4S] cluster for sulfur transfer.