Crystal structure of Pseudomonas aeruginosa RsaL bound to promoter DNA reaffirms its role as a global regulator involved in quorum-sensing.
Crystal structure of Pseudomonas aeruginosa RsaL bound to promoter DNA reaffirms its role as a global regulator involved in quorum-sensing.
复制标题
铜绿假单胞菌 RsaL 与启动子 DNA 结合的晶体结构重申了其作为参与群体感应的全局调节因子的作用
DOI：
10.1093/nar/gkw954
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发表时间：
2017-01-25
影响因子：
14.9
通讯作者：
Liang H
中科院分区：
文献类型：
--
作者：
Kang H;Gan J;Zhao J;Kong W;Zhang J;Zhu M;Li F;Song Y;Qin J;Liang H
铜绿假单胞菌具有至少三个定义良好的群体感应（QS）系统（las， rhl和pqs），这些系统控制着包括毒力在内的各种重要功能。RsaL是一种QS抑制因子，可以减少QS信号的产生，并通过与LasR相反的功能来确保体内平衡。然而，其在信号稳态中的调节作用尚不明确。在这里，我们进行了ChIP-seq分析，发现RsaL结合了两个新的靶点，PA2228/PA2229和pqsH/cdpR的基因间区域，这是PQS合成所必需的。rsaL的缺失减少了pqsH和cdpR的转录，从而减少了PQS信号的产生。ΔrsaL菌株显示出pyocyanin产量增加和生物膜形成减少，这取决于CdpR或PqsH活性。此外，我们以2.4 Å的分辨率解决了RsaL-DNA复合物的结构。虽然整体序列相似性很低，但RsaL折叠成hth样结构，在许多转录调控因子中是保守的。不同rsaL突变体的rsaL敲除细胞的互补结果进一步证实了DNA结合必需的DNA结合残基（包括Arg20、Gln27、Gln38、Gly35、Ser37和Ser42）的关键作用。我们的发现揭示了RsaL的新靶点，并为RsaL - dna相互作用的详细表征提供了见解。
Pseudomonas aeruginosa possesses at least three well-defined quorum-sensing (QS) (las, rhl and pqs) systems that control a variety of important functions including virulence. RsaL is a QS repressor that reduces QS signal production and ensures homeostasis by functioning in opposition to LasR. However, its regulatory role in signal homeostasis remains elusive. Here, we conducted a ChIP-seq assay and revealed that RsaL bound to two new targets, the intergenic regions of PA2228/PA2229 and pqsH/cdpR, which are required for PQS synthesis. Deletion of rsaL reduced transcription of pqsH and cdpR, thus decreasing PQS signal production. The ΔrsaL strain exhibited increased pyocyanin production and reduced biofilm formation, which are dependent on CdpR or PqsH activity. In addition, we solved the structure of the RsaL–DNA complex at a 2.4 Å resolution. Although the overall sequence similarity is quite low, RsaL folds into a HTH-like structure, which is conserved among many transcriptional regulators. Complementation results of the rsaL knockout cells with different rsaL mutants further confirmed the critical role of the DNA-binding residues (including Arg20, Gln27, Gln38, Gly35, Ser37 and Ser42) that are essential for DNA binding. Our findings reveal new targets of RsaL and provide insight into the detailed characterization of the RsaL–DNA interaction.