Structural basis of the arbitrium peptide-AimR communication system in the phage lysis-lysogeny decision
Structural basis of the arbitrium peptide-AimR communication system in the phage lysis-lysogeny decision
复制标题
噬菌体裂解-溶原决策中任意肽-AimR通讯系统的结构基础
DOI：
10.1038/s41564-018-0239-y
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发表时间：
2018-11-01
影响因子：
28.3
通讯作者：
Zou, Tingting
中科院分区：
文献类型：
--
作者：
Wang, Qiang;Guan, Zeyuan;Zou, Tingting
噬菌体可以在裂解周期中复制并从宿主细胞释放病毒体，或者切换到溶原过程，其中噬菌体将其自身作为原噬菌体整合到宿主基因组中。在芽孢杆菌细胞中，某些类型的芽孢杆菌使用仲裁通讯系统，该系统包含仲裁六肽、细胞受体AimR和溶原性负调节因子AimX。该系统控制溶解和溶原循环之间的决定。然而，Arbitrium肽和AimR之间的分子识别机制以及下游基因表达如何调节仍然未知。在这里，我们报告的AimR的晶体结构，从SPbeta噬菌体在载脂蛋白形式和arbitrium肽结合的形式，分别在2.20 ℃和1.92 ℃。有或没有肽，AimR通过C-末端加帽螺旋二聚化。AimR组装一个超螺旋折叠，并容纳由其tetratricopeptide重复序列包围的肽，这让人想起来自群体感应系统的RRNPP家族成员。在没有arbitrium肽的情况下，AimR靶向aimX基因的上游序列;其DNA结合活性在肽结合后被阻止。总之，我们的研究结果提供了噬菌体裂解-溶原性决定通信系统中的肽识别的结构基础。
A bacteriophage can replicate and release virions from a host cell in the lytic cycle or switch to a lysogenic process in which the phage integrates itself into the host genome as a prophage. InBacilluscells, some types of phages employ the arbitrium communication system, which contains an arbitrium hexapeptide, the cellular receptor AimR and the lysogenic negative regulator AimX. This system controls the decision between the lytic and lysogenic cycles. However, both the mechanism of molecular recognition between the arbitrium peptide and AimR and how downstream gene expression is regulated remain unknown. Here, we report crystal structures for AimR from the SPbeta phage in the apo form and the arbitrium peptide-bound form at 2.20 Å and 1.92 Å, respectively. With or without the peptide, AimR dimerizes through the C-terminal capping helix. AimR assembles a superhelical fold and accommodates the peptide encircled by its tetratricopeptide repeats, which is reminiscent of RRNPP family members from the quorum-sensing system. In the absence of the arbitrium peptide, AimR targets the upstream sequence of the aimX gene; its DNA binding activity is prevented following peptide binding. In summary, our findings provide a structural basis for peptide recognition in the phage lysis–lysogeny decision communication system.