Ankyrin-mediated self-protection during cell invasion by the bacterial predator Bdellovibrio bacteriovorus.
Ankyrin-mediated self-protection during cell invasion by the bacterial predator Bdellovibrio bacteriovorus.
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DOI：
10.1038/ncomms9884
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发表时间：
2015-12-02
影响因子：
16.6
通讯作者：
Lovering AL
中科院分区：
文献类型：
--
作者：
Lambert C;Cadby IT;Till R;Bui NK;Lerner TR;Hughes WS;Lee DJ;Alderwick LJ;Vollmer W;Sockett RE;Lovering AL
捕食性噬菌弧菌是天然抗菌生物，通过全细胞入侵杀死其他细菌。针对猎物代谢酶的自我保护对于捕食的进化非常重要。最初的猎物进入涉及捕食者的肽聚糖DD-内肽酶，它可以解交联细胞壁并防止第二个捕食者浪费性地进入。在这里，我们鉴定并表征了来自食菌芽孢杆菌的自我保护蛋白 Bd3460，它显示出真核生物细胞内病原体常见的基于锚蛋白的折叠。共晶结构揭示了 Bd3460 与双靶标的复合，结合 Bd3459 和 Bd0816 内肽酶的保守表位。络合可抑制体外肽链内切酶活性和细胞壁解交联。自我保护至关重要 - ΔBd3460 蛭弧菌在入侵时会有害地解交联自身肽聚糖，采用圆形形态，并失去捕食能力和细胞完整性。我们的分析首次对蛭弧菌的自我保护进行了机制检查，记录了两个不同基因组位点产物的保护多重性，并揭示了对入侵性捕食性细菌生活方式的重要进化适应。 噬菌蛭弧菌入侵并杀死其他细菌，但尚不清楚它如何避免自身细胞壁的降解。在这里，作者将 B. bacteriovorus 蛋白 Bd3460 鉴定为一种肽链内切酶抑制剂，可防止捕食者入侵猎物期间肽聚糖的水解。
Predatory Bdellovibrio bacteriovorus are natural antimicrobial organisms, killing other bacteria by whole-cell invasion. Self-protection against prey-metabolizing enzymes is important for the evolution of predation. Initial prey entry involves the predator's peptidoglycan DD-endopeptidases, which decrosslink cell walls and prevent wasteful entry by a second predator. Here we identify and characterize a self-protection protein from B. bacteriovorus, Bd3460, which displays an ankyrin-based fold common to intracellular pathogens of eukaryotes. Co-crystal structures reveal Bd3460 complexation of dual targets, binding a conserved epitope of each of the Bd3459 and Bd0816 endopeptidases. Complexation inhibits endopeptidase activity and cell wall decrosslinking in vitro. Self-protection is vital — ΔBd3460 Bdellovibrio deleteriously decrosslink self-peptidoglycan upon invasion, adopt a round morphology, and lose predatory capacity and cellular integrity. Our analysis provides the first mechanistic examination of self-protection in Bdellovibrio, documents protection-multiplicity for products of two different genomic loci, and reveals an important evolutionary adaptation to an invasive predatory bacterial lifestyle. The bacterium Bdellovibrio bacteriovorus invades and kills other bacteria, but it is unclear how it avoids degradation of its own cell wall. Here the authors identify the B. bacteriovorus protein Bd3460 as an endopeptidase inhibitor that prevents hydrolysis of the predator's peptidoglycan during invasion of prey.