Structural basis for native agonist and synthetic inhibitor recognition by the Pseudomonas aeruginosa quorum sensing regulator PqsR (MvfR).
Structural basis for native agonist and synthetic inhibitor recognition by the Pseudomonas aeruginosa quorum sensing regulator PqsR (MvfR).
复制标题
DOI：
10.1371/journal.ppat.1003508
复制
发表时间：
2013
期刊：
影响因子：
6.7
通讯作者：
Williams P
中科院分区：
文献类型：
--
作者：
Ilangovan A;Fletcher M;Rampioni G;Pustelny C;Rumbaugh K;Heeb S;Cámara M;Truman A;Chhabra SR;Emsley J;Williams P
细菌群体通过群体感应(QS)来协调基因表达，群体感应是一种使用可扩散信号分子的细胞间通信机制。在铜绿假单胞菌中，LysR型转录调节蛋白PqsR(MvfR)是依赖烷基喹诺酮(AQ)的QS的关键成分。PqsR被2-烷基-4-喹诺酮类化合物激活，包括假单胞菌喹诺酮信号(PQs；2-庚基-3-羟基-4(1H)-喹诺酮)、其前体2-庚基-4-羟基喹啉(HHQ)及其C9同系物2-壬基-3-羟基-4(1H)-喹诺酮(C9-PQs)和2-壬基-4-羟基喹啉(NHQ)。这些驱动AQ生物合成的自动诱导和关键毒力决定因素的上调，作为细菌种群密度的函数。因此，PqsR构成了新型抗菌剂的潜在靶点，这些抗菌剂通过阻断毒力来减轻感染。在这里，我们介绍了PqsR共诱导结合结构域(CBD)和与天然激动剂NHQ的复合体的晶体结构。我们表明，PqsR CBD的结构有一个异常大的配体结合口袋，其中天然的AQ激动剂完全通过疏水相互作用稳定。通过基于配基的设计策略，我们合成和评价了一系列50个AQ和新型喹唑烷酮(QZN)类似物，并测定了它们对AQ生物合成、毒力基因表达和生物膜发育的影响。两个异构体的简单交换(OH换成NH2)将QZN激动剂转换为拮抗剂，同时对诱导细菌毒力因子的产生产生影响。我们还测定了与PqsR结合的QZN拮抗剂的复杂晶体结构，发现其配体结合口袋中的取向与天然激动剂NHQ相似。该结构代表了LTTR-拮抗剂复合体的第一个描述。总体而言，这些研究为LTTR配体结合和基于配体的药物设计提供了新的见解，并为进一步抗P。针对AQ受体PqsR的铜绿假单胞菌毒力药物开发。细菌细胞群体通过信号分子的产生和感应，通过细胞间的交流，共同协调它们的活动。这被称为群体感应(QS)，在许多细菌中，QS控制着毒力基因的表达，其产物会损害宿主组织。因此，QS系统是抗菌剂的潜在目标，这些抗菌剂不能杀死细菌，而是阻止它们致病的能力。铜绿假单胞菌会引起广泛的人类感染，并产生大量的毒力因子。由于其中许多是受烷基喹诺酮(AQ)依赖的QS控制的，我们测定了AQ受体(PqsR)的晶体结构，以便直观地显示AQ结合部位的形状，并更好地设计PqsR抑制剂，竞争AQ结合部位从而阻断QS。这项工作与AQ类似物的化学合成相结合，导致了PqsR有效的喹唑烷酮抑制剂的发现。这些都阻碍了铜绿假单胞菌AQ和毒力因子的产生以及生物膜的发育。我们的研究为PqsR的结构提供了新的见解，并为靶向抗菌药物的开发创造了进一步的机会。
Bacterial populations co-ordinate gene expression collectively through quorum sensing (QS), a cell-to-cell communication mechanism employing diffusible signal molecules. The LysR-type transcriptional regulator (LTTR) protein PqsR (MvfR) is a key component of alkyl-quinolone (AQ)-dependent QS in Pseudomonas aeruginosa. PqsR is activated by 2-alkyl-4-quinolones including the Pseudomonas quinolone signal (PQS; 2-heptyl-3-hydroxy-4(1H)-quinolone), its precursor 2-heptyl-4-hydroxyquinoline (HHQ) and their C9 congeners, 2-nonyl-3-hydroxy-4(1H)-quinolone (C9-PQS) and 2-nonyl-4-hydroxyquinoline (NHQ). These drive the autoinduction of AQ biosynthesis and the up-regulation of key virulence determinants as a function of bacterial population density. Consequently, PqsR constitutes a potential target for novel antibacterial agents which attenuate infection through the blockade of virulence. Here we present the crystal structures of the PqsR co-inducer binding domain (CBD) and a complex with the native agonist NHQ. We show that the structure of the PqsR CBD has an unusually large ligand-binding pocket in which a native AQ agonist is stabilized entirely by hydrophobic interactions. Through a ligand-based design strategy we synthesized and evaluated a series of 50 AQ and novel quinazolinone (QZN) analogues and measured the impact on AQ biosynthesis, virulence gene expression and biofilm development. The simple exchange of two isosteres (OH for NH2) switches a QZN agonist to an antagonist with a concomitant impact on the induction of bacterial virulence factor production. We also determined the complex crystal structure of a QZN antagonist bound to PqsR revealing a similar orientation in the ligand binding pocket to the native agonist NHQ. This structure represents the first description of an LTTR-antagonist complex. Overall these studies present novel insights into LTTR ligand binding and ligand-based drug design and provide a chemical scaffold for further anti-P. aeruginosa virulence drug development by targeting the AQ receptor PqsR. Populations of bacterial cells collectively co-ordinate their activities through cell-to-cell communication via the production and sensing of signal molecules. This is called quorum sensing (QS) and in many bacteria, QS controls the expression of virulence genes, the products of which damage host tissues. Consequently, QS systems are potential targets for antimicrobial agents which do not kill bacteria but instead block their ability to cause disease. Pseudomonas aeruginosa causes a wide range of human infections and produces an armoury of virulence factors. Since many of these are controlled by alkylquinolone (AQ)-dependent QS, we determined the crystal structure of the AQ receptor (PqsR) in order to visualize the shape of the AQ-binding site and better design PqsR inhibitors which compete for the AQ binding site and so block QS. This work in conjunction with the chemical synthesis of AQ analogues resulted in the discovery of potent quinazolinone inhibitors of PqsR. These blocked AQ and virulence factor production in P. aeruginosa as well as biofilm development. Our studies present novel insights into the structure of PqsR and create further opportunities for target-based antibacterial drug development.
登录
查看更多内容
影响因子：
11.3
作者：
Heeb S;Fletcher MP;Chhabra SR;Diggle SP;Williams P;Cámara M
通讯作者：
Cámara M
影响因子：
3.6
作者：
Diggle, SP;Winzer, K;Williams, P
通讯作者：
Williams, P
影响因子：
--
作者：
Diggle, Stephen P.;Matthijs, Sandra;Williams, Paul
通讯作者：
Williams, Paul
影响因子：
4.4
作者：
Benoit, Michael R.;Conant, Carolyn G.;Matin, A.
通讯作者：
Matin, A.
影响因子：
3.6
作者：
Allesen-Holm, M;Barken, KB;Tolker-Nielsen, T
通讯作者：
Tolker-Nielsen, T