Quorum sensing is a bacterial cell-cell communication process that regulates gene expression. The search and binding of the autoinducer molecule (AHL)-bound LuxR-type proteins to specific sites on DNA in quorum-sensing cells in Gram-negative bacteria is a complex process and has been theoretically investigated based on a discrete-state stochastic approach. It is shown that several factors such as the rate of formation of the AHL-bound LuxR protein within the cells and its dissociation to freely diffusing AHL, the diffusion of the latter in and out of the cells, positive feedback loops, and the cell population density play important roles in the protein target search and can control the gene regulation processes. Physical-chemical arguments to explain these observations are presented. Our calculations of the dynamic properties are also supplemented by Monte Carlo computer simulations. Our theoretical model provides physical insights into the complex mechanisms of protein target search in quorum-sensing cells.

群体感应是一种调节基因表达的细菌细胞间通讯过程。在革兰氏阴性细菌群体感应细胞中，自诱导分子 (AHL) 结合的 LuxR 型蛋白在 DNA 上特定位点的搜索和结合是一个复杂的过程，并且已基于离散状态随机方法进行了理论上的研究。结果表明，细胞内 AHL 结合的 LuxR 蛋白的形成速率及其解离为自由扩散的 AHL、后者在细胞内外的扩散、正反馈环路和细胞群等多种因素密度在蛋白质靶标搜索中发挥重要作用，并且可以控制基因调控过程。提出了解释这些观察结果的物理化学论据。我们对动态特性的计算也得到了蒙特卡罗计算机模拟的补充。我们的理论模型为群体感应细胞中蛋白质目标搜索的复杂机制提供了物理见解。