Acyl-homoserine lactone acylase from Ralstonia strain XJ12B represents a novel and potent class of quorum-quenching enzymes
Acyl-homoserine lactone acylase from Ralstonia strain XJ12B represents a novel and potent class of quorum-quenching enzymes
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DOI：
10.1046/j.1365-2958.2003.03351.x
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发表时间：
2003-02-01
影响因子：
3.6
通讯作者：
Zhang, LH
中科院分区：
文献类型：
--
作者：
Lin, YH;Xu, JL;Zhang, LH
N - 酰基高丝氨酸内酯（AHLs）被许多群体感应型变形菌用作信号分子。多种动植物病原体利用AHLs来调控感染和毒力功能。这些信号会被AHL - 内酯酶和AHL - 酰基酶进行生物失活。此前，对于后一种机制背后的分子细节知之甚少。从一个混合物种生物膜中分离出一种AHL信号失活细菌，被鉴定为罗尔斯通氏菌属（Ralstonia sp.）。来自该生物的信号失活编码基因（我们称之为aiiD）被克隆，并在大肠杆菌中成功表达，且使所测试的三种AHLs失活。预测的794个氨基酸的多肽与犹他游动放线菌（Actinoplanes utahensis）的阿库来菌素A酰基酶（AAC）最为相似，并且与头孢菌素酰基酶和其他N - 末端（Ntn）水解酶也有显著的相似性。然而，AiiD最相似的同源物是从现有的罗尔斯通氏菌属、异常球菌属（Deinococcus）和假单胞菌属（Pseudomonas）基因组中推导出来的功能未被证实的蛋白质。液相色谱 - 质谱分析表明，AiiD水解AHL酰胺，释放出高丝氨酸内酯和相应的脂肪酸。AiiD在铜绿假单胞菌PAO1中的表达抑制了该细菌的群体感应，降低了其群游、产生弹性蛋白酶和绿脓菌素以及麻痹线虫的能力。因此，AHL - 酰基酶在抑制群体感应方面具有根本的意义，并在生物技术方面具有应用前景。
N-acylhomoserine lactones (AHLs) are used as signal molecules by many quorum-sensing Proteobacteria. Diverse plant and animal pathogens use AHLs to regulate infection and virulence functions. These signals are subject to biological inactivation by AHL-lactonases and AHL-acylases. Previously, little was known about the molecular details underlying the latter mechanism. An AHL signal-inactivating bacterium, identified as a Ralstonia sp., was isolated from a mixed-species biofilm. The signal inactivation encoding gene from this organism, which we call aiiD, was cloned and successfully expressed in Escherichia coli and inactivated three AHLs tested. The predicted 794-amino-acid polypeptide was most similar to the aculeacin A acylase (AAC) from Actinoplanes utahensis and also shared significant similarities with cephalosporin acylases and other N-terminal (Ntn) hydrolases. However, the most similar homologues of AiiD are deduced proteins of undemonstrated function from available Ralstonia, Deinococcus and Pseudomonas genomes. LC-MS analyses demonstrated that AM hydrolyses the AHL amide, releasing homoserine lactone and the corresponding fatty acid. Expression of AiiD in Pseudomonas aeruginosa PAO1 quenched quorum sensing by this bacterium, decreasing its ability to swarm, produce elastase and pyocyanin and to paralyse nematodes. Thus, AHL-acylases have fundamental implications and hold biotechnological promise in quenching quorum sensing.