A Mn-sensing riboswitch activates expression of a Mn2+/Ca2+ ATPase transporter in Streptococcus.
A Mn-sensing riboswitch activates expression of a Mn2+/Ca2+ ATPase transporter in Streptococcus.
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Mn 感应核糖开关可激活链球菌中 Mn2/Ca2 ATP 酶转运蛋白的表达。
DOI：
10.1093/nar/gkz494
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发表时间：
2019
影响因子：
14.9
通讯作者：
Giedroc,DavidP
中科院分区：
文献类型：
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作者：
Martin,JuliaE;Le,MyT;Bhattarai,Nabin;Capdevila,DaianaA;Shen,Jiangchuan;Winkler,MalcolmE;Giedroc,DavidP
维持锰（Mn）的稳态对许多细菌的毒力是重要的。在人类呼吸道病原体肺炎链球菌中，Mn特异性进口基因PsaBCA、出口基因MntE和转录调节基因PsaR建立了Mn稳态。在其他细菌中，Mn的稳态是由yybp - ykoy家族的核开关控制的。在这里，我们描述了编码pii型atp酶inS的基因上游的ayybp - ykoy家族核开关。肺炎，先前认为在Ca2+外排中起作用。我们发现gtariboswitch适体结构域采用典型的bp -yk结构，包含一个三向结，在生理浓度的Ca2+或Mn2+存在下被压实。尽管Ca2+与RNA适配体的结合比Mn2+具有更高的亲和力，但Mn2+对mgtaby转录穿透的体外激活远大于Ca2+。与此结果一致，在细胞Mn胁迫下，mgtAmRNA和蛋白水平增加约5倍，但仅在s的遗传背景下。显示出Mn2+敏感性的肺炎和枯草芽孢杆菌，表明该核糖开关作为故障安全“开启”信号，在高细胞Mn2+存在时防止Mn2+毒性。此外，我们的结果表明，这些。在这些条件下，核开关功能调节Ca2+外排。
Maintaining manganese (Mn) homeostasis is important for the virulence of numerous bacteria. In the human respiratory pathogenStreptococcus pneumoniae, the Mn-specific importer PsaBCA, exporter MntE, and transcriptional regulator PsaR establish Mn homeostasis. In other bacteria, Mn homeostasis is controlled byyybP-ykoYfamily riboswitches. Here, we characterize ayybP-ykoYfamily riboswitch upstream of themgtAgene encoding a PII-type ATPase inS. pneumoniae, suggested previously to function in Ca2+efflux. We show that themgtAriboswitch aptamer domain adopts a canonicalyybP-ykoYstructure containing a three-way junction that is compacted in the presence of Ca2+or Mn2+at a physiological Mg2+concentration. Although Ca2+binds to the RNA aptamer with higher affinity than Mn2+,in vitroactivation of transcription read-through ofmgtAby Mn2+is much greater than by Ca2+. Consistent with this result,mgtAmRNA and protein levels increase ≈5-fold during cellular Mn stress, but only in genetic backgrounds ofS. pneumoniaeandBacillus subtilisthat exhibit Mn2+sensitivity, revealing that this riboswitch functions as a failsafe ‘on’ signal to prevent Mn2+toxicity in the presence of high cellular Mn2+. In addition, our results suggest that theS. pneumoniae yybP-ykoYriboswitch functions to regulate Ca2+efflux under these conditions.