Pseudomonas aeruginosa PqsA is an anthranilate-coenzyme a ligase
Pseudomonas aeruginosa PqsA is an anthranilate-coenzyme a ligase
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DOI：
10.1128/jb.01140-07
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发表时间：
2008-02-01
影响因子：
3.2
通讯作者：
Pesci, Everett C.
中科院分区：
文献类型：
--
作者：
Coleman, James P.;Hudson, L. Lynn;Pesci, Everett C.
铜绿假单胞菌是一种机会性的人类病原体，它依赖于几个细胞间信号系统来实现毒力基因的最佳种群密度依赖性调节。假单胞菌喹诺酮信号(PQS)是由邻氨基苯甲酸与3-酮基脂肪酸缩合而成的具有2-烷基取代的3-羟基-4-喹诺酮类化合物。PqsABCDE操纵子是PQS产生所必需的，pqsA基因编码一个与酰基辅酶A(acyl-CoA)连接酶同源的蛋白。为了阐明铜绿假单胞菌4-喹诺酮合成途径的第一步，我们对pqsA基因产物的功能进行了鉴定。表达PqsA的大肠杆菌提取物能够催化邻氨基苯甲酸酯、三磷酸腺苷和辅酶A生成邻氨基苯甲酰辅酶A。将PqsA蛋白纯化为组氨酸标记的重组多肽，证明该蛋白具有邻氨基苯甲酸-辅酶A连接酶活性。该酶在多种芳香族底物上都有活性，包括苯甲酸酯和邻氨基苯甲酸酯的氯和氟衍生物。在体内观察到氯代和氟代邻氨基苯甲酸酯衍生物以及几个不是PqsA酶底物的类似物对PQS的形成有抑制作用。这些结果表明，PqsA蛋白负责启动邻氨基苯甲酸进入PQS生物合成途径，该酶可以作为潜在的药物在体外干扰铜绿假单胞菌喹诺酮信号转导的有用指示剂。
Pseudomonas aeruginosa is an opportunistic human pathogen which relies on several intercellular signaling systems for optimum population density-dependent regulation of virulence genes. The Pseudomonas quinolone signal (PQS) is a 3-hydroxy-4-quinolone with a 2-alkyl substitution which is synthesized by the condensation of anthranilic acid with a 3-keto-fatty acid. The pqsABCDE operon has been identified as being necessary for PQS production, and the pqsA gene encodes a predicted protein with homology to acyl coenzyme A (acyl-CoA) ligases. In order to elucidate the first step of the 4-quinolone synthesis pathway in P. aeruginosa, we have characterized the function of the pqsA gene product. Extracts prepared from Escherichia coli expressing PqsA were shown to catalyze the formation of anthraniloyl-CoA from anthranilate, ATP, and CoA. The PqsA protein was purified as a recombinant His-tagged polypeptide, and this protein was shown to have anthranilate-CoA ligase activity. The enzyme was active on a variety of aromatic substrates, including benzoate and chloro and fluoro derivatives of anthranilate. Inhibition of PQS formation in vivo was observed for the chloro- and fluoroanthranilate derivatives, as well as for several analogs which were not PqsA enzymatic substrates. These results indicate that the PqsA protein is responsible for priming anthranilate for entry into the PQS biosynthetic pathway and that this enzyme may serve as a useful in vitro indicator for potential agents to disrupt quinolone signaling in P. aeruginosa.