A bacterial riboswitch class for the thiamin precursor HMP-PP employs a terminator-embedded aptamer
A bacterial riboswitch class for the thiamin precursor HMP-PP employs a terminator-embedded aptamer
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DOI：
10.7554/elife.45210
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发表时间：
2019-04-05
期刊：
影响因子：
7.7
通讯作者：
Breaker, Ronald R.
中科院分区：
文献类型：
--
作者：
Atilho, Ruben M.;Arachchilage, Gayan Mirihana;Breaker, Ronald R.
我们最近实施了一个生物信息学流程，可以发现新颖但罕见的核糖开关候选物以及细菌中的其他非编码 RNA 结构。我们最初的搜索工作揭示了一个突出的候选者被称为“thiS基序”，因为它经常与编码ThiS蛋白的基因相关联，ThiS蛋白传递硫以形成硫胺素前体HET-P的噻唑部分。在本报告中，我们描述了生化和遗传数据，证明thiS基序RNA作为硫胺素前体HMP-PP的传感器发挥作用，HMP-PP与HET-P最终融合形成最终的活性辅酶硫胺素焦磷酸（TPP）。 HMP-PP 核糖开关表现出独特的结构，其中异常小的配体感应适体几乎完全嵌入其他经典的内在转录终止子茎中。这种排列产生了非常紧凑的遗传开关，细菌在这种普遍分布的辅酶的生物合成过程中用它来调节硫胺素前体的水平。
We recently implemented a bioinformatics pipeline that can uncover novel, but rare, riboswitch candidates as well as other noncoding RNA structures in bacteria. A prominent candidate revealed by our initial search efforts was called the 'thiS motif ' because of its frequent association with a gene coding for the ThiS protein, which delivers sulfur to form the thiazole moiety of the thiamin precursor HET-P. In the current report, we describe biochemical and genetic data demonstrating that thiS motif RNAs function as sensors of the thiamin precursor HMP-PP, which is fused with HET-P ultimately to form the final active coenzyme thiamin pyrophosphate (TPP). HMP-PP riboswitches exhibit a distinctive architecture wherein an unusually small ligand-sensing aptamer is almost entirely embedded within an otherwise classic intrinsic transcription terminator stem. This arrangement yields remarkably compact genetic switches that bacteria use to tune the levels of thiamin precursors during the biosynthesis of this universally distributed coenzyme.