Sinorhizobium meliloti, a bacterium lacking the autoinducer-2 (AI-2) synthase, responds to AI-2 supplied by other bacteria.
Sinorhizobium meliloti, a bacterium lacking the autoinducer-2 (AI-2) synthase, responds to AI-2 supplied by other bacteria.
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DOI：
10.1111/j.1365-2958.2008.06477.x
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发表时间：
2008-12
影响因子：
3.6
通讯作者：
Miller ST
中科院分区：
文献类型：
--
作者：
Pereira CS;McAuley JR;Taga ME;Xavier KB;Miller ST
许多细菌通过调节不同的生态位特异性基因来响应群体感应信号自动诱导器-2(AI-2)。在这里，我们展示了苜蓿中华根瘤菌，一种缺乏AI-2合成酶基因的植物共生体，虽然不能产生AI-2，但仍然可以对其他物种产生的AI-2做出反应。我们证明了苜蓿链霉菌有一个与AI-2结合的周质结合蛋白。该蛋白(这里称为SmLsrB)及其配体的晶体结构表明，它与(2R，4S)-2-methyl-2，3，3，4-tetrahydroxytetrahydrofuran(R-THMF)结合，这与鼠伤寒沙门氏菌LsrB识别的AI-2异构体相同。编码SmLsrB的基因位于操纵子中，与肠道细菌中AI-2内化所需的LSR基因同源。因此，苜蓿链霉菌内化外源AI-2，而该操纵子中的突变体在AI-2内化方面存在缺陷。苜蓿链霉菌没有从内化AI-2中获得代谢优势，这表明AI-2在苜蓿链霉菌中起信号作用。此外，苜蓿链霉菌可以完全消除胡萝卜欧文氏菌分泌的AI-2，这是一种利用AI-2调节毒力的植物病原菌。我们的发现表明，苜蓿能够‘窃听’其他物种的AI-2信号，并干扰AI-2调节的行为，如毒力。
Many bacterial species respond to the quorum sensing signal autoinducer-2 (AI-2) by regulating different niche specific genes. Here, we show that Sinorhizobium meliloti, a plant symbiont lacking the gene for the AI-2 synthase, while not capable of producing AI-2 can nonetheless respond to AI-2 produced by other species. We demonstrate that S. meliloti has a periplasmic binding protein that binds AI-2. The crystal structure of this protein (here named SmLsrB) with its ligand reveals that it binds (2R,4S)-2-methyl-2,3,3,4-tetrahydroxytetrahydrofuran (R-THMF), the identical AI-2 isomer recognized by LsrB of Salmonella typhimurium. The gene encoding SmLsrB is in an operon with orthologs of the lsr genes required for AI-2 internalization in enteric bacteria. Accordingly, S. meliloti internalizes exogenous AI-2, and mutants in this operon are defective in AI-2 internalization. S. meliloti does not gain a metabolic benefit from internalizing AI-2, suggesting that AI-2 functions as a signal in S. meliloti. Furthermore, S. meliloti can completely eliminate the AI-2 secreted by Erwinia carotovora, a plant pathogen shown to use AI-2 to regulate virulence. Our findings suggest that S. meliloti is capable of ‘eavesdropping’ on the AI-2 signaling of other species and interfering with AI-2-regulated behaviors such as virulence.
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DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
3.6
作者：
Hammer, BK;Bassler, BL
通讯作者：
Bassler, BL
影响因子：
3.6
作者：
BASSLER, BL;WRIGHT, M;SILVERMAN, MR
通讯作者：
SILVERMAN, MR
影响因子：
3.6
作者：
BASSLER, BL;WRIGHT, M;SILVERMAN, MR
通讯作者：
SILVERMAN, MR
影响因子：
4.2
作者：
Li, Min;Villaruz, Amer E.;Vadyvaloo, Viveka;Sturdevant, Daniel E.;Otto, Michael
通讯作者：
Otto, Michael