Declerck Nathalie, Bouillaut Laurent, Chaix Denis, Rugani Nathalie, Slamti Leyla, Hoh François, Lereclus Didier, Arold Stefan T
Institut National de la Santé et de la Recherche Médicale, Unité 554, and Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5048, Centre de Biochimie Structurale, Université de Montpellier, 34090 Montpellier, France.
Proc Natl Acad Sci U S A. 2007 Nov 20;104(47):18490-5. doi: 10.1073/pnas.0704501104. Epub 2007 Nov 12.
Gram-positive bacteria use a wealth of extracellular signaling peptides, so-called autoinducers, to regulate gene expression according to population densities. These "quorum sensing" systems control vital processes such as virulence, sporulation, and gene transfer. Using x-ray analysis, we determined the structure of PlcR, the major virulence regulator of the Bacillus cereus group, and obtained mechanistic insights into the effects of autoinducer binding. Our structural and phylogenetic analysis further suggests that all of those quorum sensors that bind directly to their autoinducer peptide derive from a common ancestor and form a single family (the RNPP family, for Rap/NprR/PlcR/PrgX) with conserved features. As a consequence, fundamentally different processes in different bacterial genera appear regulated by essentially the same autoinducer recognition mechanism. Our results shed light on virulence control by PlcR and elucidate origin and evolution of multicellular behavior in bacteria.
革兰氏阳性菌利用大量细胞外信号肽（即所谓的自诱导物）根据群体密度调节基因表达。这些“群体感应”系统控制着诸如毒力、孢子形成和基因转移等重要过程。通过X射线分析，我们确定了蜡样芽孢杆菌群主要毒力调节因子PlcR的结构，并获得了关于自诱导物结合作用的机制性见解。我们的结构和系统发育分析进一步表明，所有直接与其自诱导肽结合的群体感应传感器都起源于一个共同祖先，并形成了一个具有保守特征的单一家族（Rap/NprR/PlcR/PrgX的RNPP家族）。因此，不同细菌属中根本不同的过程似乎受基本相同的自诱导物识别机制调控。我们的研究结果揭示了PlcR对毒力的控制，并阐明了细菌中多细胞行为的起源和进化。
