Reconfiguring the Quorum-Sensing Regulator SdiA of Escherichia coli To Control Biofilm Formation via Indole and N-Acylhomoserine Lactones
Reconfiguring the Quorum-Sensing Regulator SdiA of Escherichia coli To Control Biofilm Formation via Indole and N-Acylhomoserine Lactones
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DOI：
10.1128/aem.02081-08
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发表时间：
2009-03-01
影响因子：
4.4
通讯作者：
Wood, Thomas K.
中科院分区：
文献类型：
--
作者：
Lee, Jintae;Maeda, Toshinari;Wood, Thomas K.
SdiA是一种群体感应调节器的同系物，它检测来自其他细菌的N-酰基高丝氨酸内酯(AHL)信号。在AHL和自身信号吲哚存在的情况下，大肠杆菌使用SdiA来减少其生物膜的形成。在这里，我们重新配置SdiA(240个氨基酸)，以使用蛋白质工程控制生物膜的形成。获得了4个生物被膜形成发生改变的SdiA变异体，包括截断变异体SdiA1E11(F7L、F59L、Y70C、M94K和K153X)和SdiA14C3(W9R、P49T、N87T、N96和L123X处的移码)，与野生型SdiA相比，在内源吲哚存在下，SdiA生物被膜的形成减少了5-20倍。全转录组图谱显示，与不表达SdiA时相比，野生型SdiA通过抑制与吲哚合成和卷曲合成相关的基因而减少了生物膜的形成，而与野生型SdiA相比，突变体SdiA1E11诱导了与吲哚合成相关的基因。这些结果表明吲哚代谢发生了改变，并证实了DNA微阵列在吲哚合成方面的结果，变异SdiA1E11产生的吲哚增加了九倍，这导致游泳运动和细胞密度降低。此外，与野生型SdiA相比，野生型SdiA减少了卷曲的产生和tna A的转录，而SdiA1E11则增加了tna A的转录(tna A编码色氨酶，形成吲哚)。因此，野生型SdiA通过减少卷曲的产生和运动来减少生物膜的形成，而SdiA1E11通过吲哚减少生物膜的形成。此外，AHL敏感突变体(SdiA2D10，在E31G、Y42F、R116H和L165Q有四个突变)在N-辛酰基-DL-高丝氨酸内酯和N-(3-氧代十二烷酰)-L-高丝氨酸内酯存在下，生物被膜形成增加7倍。因此，SdiA可以进化来增加或减少生物膜的形成，并且生物膜的形成可以通过改变传感器而不是信号来控制。
SdiA is a homolog of quorum-sensing regulators that detects N-acylhomoserine lactone (AHL) signals from other bacteria. Escherichia coli uses SdiA to reduce its biofilm formation in the presence of both AHLs and its own signal indole. Here we reconfigured SdiA (240 amino acids) to control biofilm formation using protein engineering. Four SdiA variants were obtained with altered biofilm formation, including truncation variants SdiA1E11 (F7L, F59L, Y70C, M94K, and K153X) and SdiA14C3 (W9R, P49T, N87T, frameshift at N96, and L123X), which reduced biofilm formation by 5- to 20-fold compared to wild-type SdiA in the presence of endogenous indole. Whole-transcriptome profiling revealed that wild-type SdiA reduced biofilm formation by repressing genes related to indole synthesis and curli synthesis compared to when no SdiA was expressed, while variant SdiA1E11 induced genes related to indole synthesis in comparison to wild-type SdiA. These results suggested altered indole metabolism, and corroborating the DNA microarray results in regard to indole synthesis, variant SdiA1E11 produced ninefold more indole, which led to reduced swimming motility and cell density. Also, wild-type SdiA decreased curli production and tnaA transcription, while SdiA1E11 increased tnaA transcription (tnaA encodes tryptophanase, which forms indole) compared to wild-type SdiA. Hence, wild-type SdiA decreased biofilm formation by reducing curli production and motility, and SdiA1E11 reduced biofilm formation via indole. Furthermore, an AHL-sensitive variant (SdiA2D10, having four mutations at E31G, Y42F, R116H, and L165Q) increased biofilm formation sevenfold in the presence of N-octanoyl-DL-homoserine lactone and N-(3-oxododecatanoyl)-L-homoserine lactone. Therefore, SdiA can be evolved to increase or decrease biofilm formation, and biofilm formation may be controlled by altering sensors rather than signals.