Generation of cell-to-cell signals in quorum sensing: Acyl homoserine lactone synthase activity of a purified Vibrio fescheri LuxI protein
Generation of cell-to-cell signals in quorum sensing: Acyl homoserine lactone synthase activity of a purified Vibrio fescheri LuxI protein
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DOI：
10.1073/pnas.93.18.9505
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发表时间：
1996-09-03
影响因子：
11.1
通讯作者：
Greenberg, EP
中科院分区：
文献类型：
--
作者：
Schaefer, AL;Val, DL;Greenberg, EP
许多细菌利用酰基高丝氨酸内酯信号来监测细胞密度，这是一种称为群体感应和反应的基因调控类型，这些信号的合成是由费氏弧菌luxI基因的同源物指导的，这种通讯解决了关于费氏弧菌信号合成的两个关键问题。(i)luxI产物直接参与信号合成--该蛋白是酰基高丝氨酸内酯合酶;和（ii）酰基高丝氨酸内酯合成的底物不是来自生物合成途径的氨基酸或脂肪酸降解产物，而是来自脂肪酸生物合成途径的S-腺苷甲硫氨酸（SAM）和酰化酰基载体蛋白（ACP），我们纯化了麦芽糖结合蛋白-LuxI融合多肽，并表明，当提供适当的底物时，它催化酰基高丝氨酸内酯的合成。在费氏弧菌中，LuxI指导N-（3-氧代己酰基）高丝氨酸内酯和己酰基高丝氨酸内酯的合成。纯化的麦芽糖结合蛋白-LuxI融合蛋白催化由己酰-ACP和SAM合成己酰高丝氨酸内酯，对具有不同酰基长度的ACP具有高水平的己酰-ACP特异性，并且当SAM被其他氨基酸如甲硫氨酸、S-腺苷高半胱氨酸、高丝氨酸或高丝氨酸内酯取代时，不合成己酰高丝氨酸内酯，或当提供己酰基-SAM作为底物时。这提供了直接证据，表明LuxI蛋白是一种自诱导物合酶，其催化SAM和脂肪酰基-ACP之间的酰胺键形成，然后催化酰基-SAM中间体形成酰基高丝氨酸内酯。
Many bacteria use acyl homoserine lactone signals to monitor cell density in a type of gene regulation termed quorum sensing and response, Synthesis of these signals is directed by homologs of the luxI gene of Vibrio fischeri, This communication resolves two critical issues concerning the synthesis of the V. fischeri signal. (i) The luxI product is directly involved in signal synthesis-the protein is an acyl homoserine lactone synthase; and (ii) the substrates for acyl homoserine lactone synthesis are not amino acids from biosynthetic pathways or fatty acid degradation products, but rather they are S-adenosylmethionine (SAM) and an acylated acyl carrier protein (ACP) from the fatty acid biosynthesis pathway, We purified a maltose binding protein-LuxI fusion polypeptide and showed that, when provided with the appropriate substrates, it catalyzes the synthesis of an acyl homoserine lactone, In V. fischeri, luxI directs the synthesis of N-(3-oxohexanoyl)homoserine lactone and hexanoyl homoserine lactone. The purified maltose binding protein-LuxI fusion protein catalyzes the synthesis of hexanoyl homoserine lactone from hexanoyl-ACP and SAM, There is a high level of specificity for hexanoyl-ACP over ACPs with differing acyl group lengths, and hexanoyl homoserine lactone was not synthesized when SAM was replaced with other amino acids, such as methionine, S-adenosylhomocysteine, homoserine, or homoserine lactone, or when hexanoyl-SAM was provided as the substrate. This provides direct evidence that the LuxI protein is an autoinducer synthase that catalyzes the formation of an amide bond between SAM and a fatty acyl-ACP and then catalyzes the formation of the acyl homoserine lactone from the acyl-SAM intermediate.