AI-2 Mediated Quorum Sensing in Vibrio harveyi.

描述（由申请人提供）：细菌通过分泌和检测小信号分子相互交流并协调群落的行为，这种现象称为群体感应。拟议的研究将调查如何从细胞外信号分子的信息是跨膜转导，以调节基因表达。具体而言，新发现的和广泛的细菌AI-2自诱导分子和其受体LuxPQ在哈维氏弧菌之间的相互作用的特点。具体目标是：1.识别影响与AI-2和LuxQ相互作用的LuxP突变。将在LuxP中产生模拟AI-2结合形式的功能获得突变。还将鉴定不能与AI-2或LuxQ相互作用的显性LuxP突变。2.鉴定影响与LuxP相互作用的LuxQ周质结构域中的突变。基于PCR的诱变策略将用于产生增强LuxQ与LuxP相互作用的突变。还将在LuxQ中分离突变，其抑制在Aim 1中分离的LuxP的显性突变等位基因。3.测试AI-2类似物的激动剂或拮抗剂活性。将测量每种合成类似物对纯化LuxP的结合亲和力，并与体内AI-2活性进行比较。

DESCRIPTION (provided by applicant): Bacteria communicate with one another and coordinate the behavior of the community by means of secretion and detection of small signaling molecules, and this phenomenon is termed quorum sensing. The proposed research will investigate how the information from an extracellular signaling molecule is transduced across a membrane to regulate gene expression. Specifically, the interactions between the newly discovered and widespread bacterial AI-2 autoinducer molecule and its receptor LuxPQ in Vibrio harveyi will be characterized. The specific aims are: 1. Identify mutations in LuxP that affect interaction with AI-2 and with LuxQ. Gain of function mutations will be generated in LuxP that mimic the AI-2-bound form. Dominant LuxP mutations will also be identified that are unable to interact with AI-2 or with LuxQ. 2. Identify mutations in the periplasmic domain of LuxQ that affect interaction with LuxP. A PCR-based mutagenesis strategy will be used to generate mutations that enhance LuxQ's interaction with LuxP. Mutations will also be isolated in LuxQ that suppress dominant mutant alleles of LuxP isolated in Aim 1. 3. Test AI-2 analogs for agonist or antagonist activity. The binding affinities of each synthetic analog for purified LuxP will be measured and compared to AI-2 activity in vivo.