The quorum-quenching N-acyl homoserine lactone acylase PvdQ is an Ntn-hydrolase with an unusual substrate-binding pocket
The quorum-quenching N-acyl homoserine lactone acylase PvdQ is an Ntn-hydrolase with an unusual substrate-binding pocket
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DOI：
10.1073/pnas.0911839107
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发表时间：
2010-01-12
影响因子：
11.1
通讯作者：
Dijkstra, Bauke W.
中科院分区：
文献类型：
--
作者：
Bokhove, Marcel;Jimenez, Pol Nadal;Dijkstra, Bauke W.
在许多革兰氏阴性病原体中，它们的毒力行为是通过群体感应来调节的，其中 N-酰基高丝氨酸内酯 (AHL) 等可扩散信号充当化学信息化合物。这些可扩散信号的酶促降解，例如。例如，内酯酶或酰胺水解酶消除 AHL 调节的毒力，这一过程称为群体淬灭。在这里，我们报道了 AHL 酰胺水解酶的第一个晶体结构，即来自铜绿假单胞菌的 AHL 酰基转移酶 PvdQ。 PvdQ 具有典型的 α/β 异二聚体 Ntn 水解酶折叠，类似于青霉素 G 酰基转移酶和头孢菌素酰基转移酶。然而，它具有独特的、异常大的疏水性结合袋，非常适合识别 AHL 的 C12 脂肪酸样链。 C12 脂肪酸或 3-oxo-C12 脂肪酸的结合会引起细微的构象变化以适应脂肪链。此外，共价酯中间体的结构将 Ser beta 1 识别为亲核试剂，将 Asn beta 269 和 Val beta 70 识别为 AHL 降解过程中的氧阴离子孔残基。我们的结构显示了 Ntn-水解酶支架的多功能性，并且可以作为具有类似底物偏好的 Ntn-水解酶的结构范例。最后，PvdQ 的群体淬灭能力可用于抑制病原体的群体感应机制。
In many Gram-negative pathogens, their virulent behavior is regulated by quorum sensing, in which diffusible signals such as N-acyl homoserine lactones (AHLs) act as chemical messaging compounds. Enzymatic degradation of these diffusible signals by, e. g., lactonases or amidohydrolases abolishes AHL regulated virulence, a process known as quorum quenching. Here we report the first crystal structure of an AHL amidohydrolase, the AHL acylase PvdQ from Pseudomonas aeruginosa. PvdQ has a typical alpha/beta heterodimeric Ntn-hydrolase fold, similar to penicillin G acylase and cephalosporin acylase. However, it has a distinct, unusually large, hydrophobic binding pocket, ideally suited to recognize C12 fatty acid-like chains of AHLs. Binding of a C12 fatty acid or a 3-oxo-C12 fatty acid induces subtle conformational changes to accommodate the aliphatic chain. Furthermore, the structure of a covalent ester intermediate identifies Ser beta 1 as the nucleophile and Asn beta 269 and Val beta 70 as the oxyanion hole residues in the AHL degradation process. Our structures show the versatility of the Ntn-hydrolase scaffold and can serve as a structural paradigm for Ntn-hydrolases with similar substrate preference. Finally, the quorum-quenching capabilities of PvdQ may be utilized to suppress the quorum-sensing machinery of pathogens.