Sulfur Availability Impacts Accumulation of the 2-Thiouridine tRNA Modification in Bacillus subtilis
Sulfur Availability Impacts Accumulation of the 2-Thiouridine tRNA Modification in Bacillus subtilis
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DOI：
10.1128/jb.00009-22
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发表时间：
2022-04-25
影响因子：
3.2
通讯作者：
Dos Santos，Patricia C.
中科院分区：
文献类型：
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作者：
Edwards，Ashley M.;Black，Katherine A.;Dos Santos，Patricia C.
tRNA的转录后修饰是这些接头分子折叠和功能的关键因素。tRNA中的硫修饰是由作用于同源tRNA底物的特定位置的专门酶安装的。大多数研究的生物体含有一种通用的半胱氨酸脱硫酶，用于调动硫来合成S-tRNA和其他硫代辅助因子。枯草芽孢杆菌和其他革兰氏阳性细菌编码多种半胱氨酸脱硫酶，与特定的硫受体在硫辅因子的生物合成中合作。这种代谢布局表明在这些生物合成途径中有另一种调节模式。在这项研究中，tRNA修饰被用作与半胱氨酸脱硫有关的途径功能的读数。这些分析表明，2-硫脲修饰tRNA （s2U）的相对丰度与生长介质中硫的可用性呈剂量依赖性。本研究发现，低硫浓度导致s2U半胱氨酸脱硫酶YrvO和硫脲酰化酶MnmA的水平降低，而其他半胱氨酸脱硫酶SufS、NifS和NifZ的水平未发生变化。对依赖于半胱氨酸脱硫酶活性的途径代谢物的分析表明，硫养分有效性特异性地影响s2U的积累，而对其他s修饰的tRNA水平或Fe-S酶的活性水平没有影响。总的来说，这些结果支持s2U tRNA作为枯草芽孢杆菌硫可用性标记的模型。重要性2-硫脲（s2U） tRNA修饰在生命的各个领域普遍存在。参与这种修饰的酶YrvO和MnmA在枯草芽孢杆菌中是必不可少的，这证实了s2U在维持翻译效率和细胞活力方面的良好作用。在这里，我们表明，在模型革兰氏阳性菌枯草芽孢杆菌中，s2U的水平对硫的可用性有响应。s2U生物合成成分的下调导致s2U水平降低，这可能是细胞营养不足时翻译装置减慢的信号。我们的研究结果为鉴定s代谢物消耗过程中潜在的细菌调节模式提供了基础，该模式可能使用s2U作为次优代谢状态的标记。
Posttranscriptional modifications to tRNA are critical elements for the folding and functionality of these adaptor molecules. Sulfur modifications in tRNA are installed by specialized enzymes that act on cognate tRNA substrates at specific locations. Most studied organisms contain a general cysteine desulfurase to mobilize sulfur for the synthesis of S-tRNA and other thio-cofactors. Bacillus subtilis and other Gram-positive bacteria encode multiple cysteine desulfurases that partner with specific sulfur acceptors in the biosynthesis of thio-cofactors. This metabolic layout suggests an alternate mode of regulation in these biosynthetic pathways. In this study, tRNA modifications were exploited as a readout for the functionality of pathways involving cysteine desulfurases. These analyses showed that the relative abundance of 2-thiouridine-modified tRNA (s2U) responds to sulfur availability in the growth medium in a dose-dependent manner. This study found that low sulfur concentrations lead to decreased levels of the s2U cysteine desulfurase YrvO and thiouridylase MnmA, without altering the levels of other cysteine desulfurases, SufS, NifS, and NifZ. Analysis of pathway metabolites that depend on the activity of cysteine desulfurases indicates that sulfur nutrient availability specifically impacts s2U accumulation while having no effect on the levels of other S-modified tRNA or activity levels of Fe-S enzymes. Collectively, these results support a model in which s2U tRNA serves as a marker for sulfur availability in B. subtilis.IMPORTANCEThe 2-thiouridine (s2U) tRNA modification is found ubiquitously across all domains of life. YrvO and MnmA, the enzymes involved in this modification, are essential in B. subtilis, confirming the well-established role of s2U in maintaining translational efficiency and, consequently, cellular viability. Herein, we show that in the model Gram-positive organism Bacillus subtilis, the levels of s2U are responsive to sulfur availability. Downregulation of the s2U biosynthetic components leads to lower s2U levels, which may serve as a signal for the slowing of the translational apparatus during cellular nutrient insufficiency. Our findings provide the basis for the identification of a potential bacterial mode of regulation during S-metabolite depletion that may use s2U as a marker of suboptimal metabolic status.