Cabrera Rosina, Rodríguez-Romero Adela, Guarneros Gabriel, de la Torre Mayra
Centro de Investigación en Alimentación y Desarrollo A. C., Hermosillo, Mexico.
Instituto de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, México.
FEBS Lett. 2016 Sep;590(18):3243-53. doi: 10.1002/1873-3468.12371. Epub 2016 Sep 2.
The NprR protein and NprRB signaling peptide comprise a bifunctional quorum-sensing system from the Bacillus cereus group that is involved in transcriptional activation through DNA-binding and in sporulation initiation by binding to Spo0F. We characterized in vitro the direct interactions established by NprR that may be relevant for performing its two functions. Apo-NprR interacted with Spo0F, but not with the target DNA. The NprRB signaling peptide SSKPDIVG that binds strongly to Apo-NprR, failed to bind and disrupt the NprR-Spo0F complex. Finally, the NprR-NprRB complex bound both to Spo0F and the target DNA with similar affinity. Based on our findings, we propose that rather than a switch triggered by NprRB, the NprR/NprRB ratio and the availability of Spo0F binding sites define the function of NprR.
NprR蛋白和NprRB信号肽构成了蜡样芽孢杆菌属的一种双功能群体感应系统，该系统通过DNA结合参与转录激活，并通过与Spo0F结合参与芽孢形成起始。我们在体外对NprR建立的可能与其两种功能相关的直接相互作用进行了表征。脱辅基NprR与Spo0F相互作用，但不与靶DNA相互作用。与脱辅基NprR强烈结合的NprRB信号肽SSKPDIVG未能结合并破坏NprR-Spo0F复合物。最后，NprR-NprRB复合物以相似的亲和力与Spo0F和靶DNA结合。基于我们的发现，我们提出，定义NprR功能的不是由NprRB触发的开关，而是NprR/NprRB的比例和Spo0F结合位点的可用性。
