Basic studies on design of artificial chemical language compounds for cell-to-cell communication in Gram-negative bacteria.

许多革兰氏阴性菌通过使用N-酰基-L-高丝氨酸内酯（AHL）作为“化学语言”进行相互交流。这种细胞与细胞之间的交流被称为群体感应。我们合成了一系列AHL类似物，并测试了它们作为“化学语言”的功能。研究发现，N-酰基环戊酰胺类化合物对铜绿假单胞菌群体感应有抑制作用。N-癸酰基环戊酰胺（C10-CPA）是目前合成的N-酰基环戊酰胺类化合物中最强的拮抗剂。C10-CPA抑制致病因子包括弹性蛋白酶、鼠李糖脂和绿脓菌素的产生以及铜绿假单胞菌生物膜的形成。遗传分析表明，C10-CPA抑制合成AHL的LasI的酶活性。LasR和RhlR是群体感应中的调节蛋白，被认为对于评估作为人工化学语言的合成化合物是重要的。我们成功地在大肠杆菌中过表达lasR和rhlR基因并纯化它们。我们还证实了纯化的LasR和RhlR保留了结合其同源DNA结合位点的能力。

Many Gram-negative bacteria communicate with each other by using N-acyl-L-homoserine lactone (AHL) as "chemical language"". This cell-to-cell communication is called quorum sensing. We synthesized a series of AHL analogs and tested them for functioning as "chemical language". It was found that N-acyl-cyclopentylamides show inhibitory effects on quorum sensing in Pseudomonas aeruginosa. N-Decanoylcyclopentylamide (C10-CPA) is the strongest antagonist among N-acylcyclopentylamides synthesized. C10-CPA inhibits production of pathogenic factors including elastase, rhamnolipid, and pyocyanin as well as biofilm formation in P.aeruginosa.. Genetic analysis suggested that C10-CPA inhibits enzymatic activity of LasI, which synthesizes AHL. LasR and RhlR, which are regulatory proteins in quorum sensing, are thought to be important for evaluating synthesized compounds as artificial chemical languages. We successfully overexpressed the lasR and rhlR genes in Escherichia coli and purified them. We also confirmed that purified LasR and RhlR retain the ability to bind to their cognate DNA binding sites.