Increasing AIP Macrocycle Size Reveals Key Features of agr Activation in Staphylococcus aureus.
Increasing AIP Macrocycle Size Reveals Key Features of agr Activation in Staphylococcus aureus.
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增加AIP大环的大小揭示了金黄色葡萄球菌中AGR激活的关键特征。
DOI：
10.1002/cbic.201500006
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发表时间：
2015-05-04
期刊：
影响因子：
--
通讯作者：
Muir TW
中科院分区：
文献类型：
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作者：
Johnson JG;Wang B;Debelouchina GT;Novick RP;Muir TW
人类病原体金黄色葡萄球菌中的agr基因座是具有等位基因变异性的双启动子调节子，其产生参与调节细菌内毒力的群体感应电路。独特的自诱导肽（AIP）的分泌和通过跨膜受体组氨酸激酶AgrC检测其浓度，协调局部细菌种群密度与基因表达的全局变化。这一发现，葡萄球菌的毒力可以通过拮抗这种群体感应途径抑制激发了巨大的兴趣，了解潜在的AIP-AgrC相互作用的结构-活性关系。AIP的定义结构特征是一个16元含硫代内酯的大环。令人惊讶的是，环的大小对agr的激活或抑制的重要性尚未探讨。在这项研究中，我们通过合成和功能分析的AIP类似物具有扩大和减少的大环来解决这一不足。值得注意的是，这项研究是第一次询问AIP功能，既建立了基于细胞的报告基因测定和新开发的体外AgrC-I结合和自磷酸化活性测定。基于我们的数据，我们提出了一个强大的agr激活模型，涉及合作，3点的AIP大环和AgRC之间的接触相互作用。
The agr locus in the commensal human pathogen, Staphylococcus aureus, is a two-promoter regulon with allelic variability that produces a quorum-sensing circuit involved in regulating virulence within the bacterium. Secretion of unique autoinducing peptides (AIPs) and detection of their concentration via AgrC, a transmembrane receptor histidine kinase, coordinates local bacterial population density with global changes in gene expression. The finding that staphylococcal virulence can be inhibited through antagonism of this quorum-sensing pathway has fueled tremendous interest in understanding the structure-activity relationships underlying the AIP-AgrC interaction. The defining structural feature of the AIP is a 16-membered, thiolactone-containing macrocycle. Surprisingly, the importance of ring size on agr activation or inhibition has not been explored. In this study, we address this deficiency through the synthesis and functional analysis of AIP analogs featuring enlarged and reduced macrocycles. Notably, this study is the first to interrogate AIP function using both established cell-based reporter gene assays and newly developed in vitro AgrC-I binding and autophosphorylation activity assays. Based on our data, we present a model for robust agr activation involving a cooperative, 3-points-of-contact interaction between the AIP macrocycle and AgrC.