Mechanistic Insights into Sulfur Relay by Multiple Sulfur Mediators Involved in Thiouridine Biosynthesis at tRNA Wobble Positions
Mechanistic Insights into Sulfur Relay by Multiple Sulfur Mediators Involved in Thiouridine Biosynthesis at tRNA Wobble Positions
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DOI：
10.1016/j.molcel.2005.11.001
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发表时间：
2006-01-06
期刊：
影响因子：
16
通讯作者：
Suzuki, T
中科院分区：
文献类型：
--
作者：
Ikeuchi, Y;Shigi, N;Suzuki, T
负责NNR密码子的细菌trna的摆动碱基被修饰为5-甲基胺甲基-2-硫脲(mnm（5)s(2)U）。mnm(5)s(2)U的2-硫修饰是准确解码和正常细胞生长所必需的。我们通过系统的全基因组筛选（“核糖核体分析”）鉴定了5个基因yhhP、yheL、yheM、yheN和yccK（分别命名为tusA、tusB、tusC、tusD和tusE），它们对mnm5s2U的2-硫脲酰化至关重要。利用重组TusA、TusBCD复合物、TusE和先前鉴定的IscS和MnmA，在体外构建了高效的2-硫脲形成。IscS的脱硫酶活性受到TusA结合的刺激。IscS将过硫化物硫转移到TusA。TusE结合TusBCD复合物，刺激硫从TusA转移到TusD。TusE也与MnmA-tRNA复合物相互作用。这项研究表明，2-硫脲的形成是通过一个复杂的硫中继系统进行的，该系统由多种硫介质组成，这些介质选择并促进特定的硫从各种硫运输途径流向2-硫脲。
The wobble bases of bacterial tRNAs responsible for NNR codons are modified to 5-methylaminomethyl-2-thiouridine (mnm(5)s(2)U). 2-thio modification of mnm(5)s(2)U is required for accurate decoding and essential for normal cell growth. We identified five genes yhhP, yheL, yheM, yheN, and yccK(named tusA, tusB, tusC, tusD, and tusE, respectively) that are essential for 2-thiouri-dylation of mnm5s2U by a systematic genome-wide screen ('' ribonucleome analysis ''). Efficient 2-thiouridine formation in vitro was reconstituted with recombinant TusA, a TusBCD complex, TusE, and previously identified IscS and MnmA. The desulfurase activity of IscS is stimulated by TusA binding. IscS transfers the persulfide sulfur to TusA. TusE binds TusBCD complex and stimulates sulfur transfer from TusA to TusD. TusE also interacts with an MnmA-tRNA complex. This study revealed that 2-thiouridine formation proceeds through a complex sulfur-relay system composed of multiple sulfur mediators that select and facilitate specific sulfur flow to 2-thiouridine from various pathways of sulfur trafficking.