吲哚是一种广泛存在于微生物中的种间/种内通讯信号分子。但是，目前对吲哚所介导的信号通讯的分子机制还不是十分清楚。我们的前期数据表明吲哚作为信号分子能够广泛的影响和调节荧光假单胞菌2P24的生理学活动；通过定量蛋白质组学手段我们发现吲哚能够调节药物外排泵基因EmhABC和莫匹罗星合成相关的基因簇mup的表达。本项目中，我们计划研究转录因子EmhR识别吲哚并调控外排泵基因emhABC表达的分子机制；通过解析EmhR、EmhR-indole以及EmhR-DNA复合体的晶体结构阐明由吲哚引起的EmhR发生变构的机制；进一步弄清吲哚如何通过群体感应系统pcoI/pcoR调控莫匹罗星生物合成。该项目的完成能够极大加深我们对吲哚介导的种间信号通讯的分子机制的理解。

Indole is ubiquitously synthesized by microbes and functions as an important inter-species/intra-species signaling molecule. However，the molecule mechanism of indole signaling is still elusive. We have shown that indole can influence diverse aspects of physiological activities of Pseudomonas fluorescens 2P24. By using the label-free quantification proteomic method, we further demonstrated that indole induced the expression the emhABC operon encoding the drug efflux pump while suppressed the expression of the mup operon involved muporocin biosynthesis. In this proposal, we are planning to study how the indole molecule is sensed by the TetR-family transcription regulator EmhR and regulates the expression of emhABC. By solving the crystal structures of EmhR, EmhR-indole and EmhR-DNA complex, we are trying to illustrate the mechanism of indole triggering the conformational changes of EmhR. In addition, how the indole molecule influences the biosynthesis of mupirocin through the quorum sensing system pcoI/pcoR will also be investigated.Taken together,our study will have important implications on the general action mechanism for the indole molecule functioning in inter-species signaling.