More than a hole: the holin lethal function may be required to fully sensitize bacteria to the lytic action of canonical endolysins
More than a hole: the holin lethal function may be required to fully sensitize bacteria to the lytic action of canonical endolysins
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DOI：
10.1111/mmi.13448
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发表时间：
2016-10-01
影响因子：
3.6
通讯作者：
Sao-Jose, Carlos
中科院分区：
文献类型：
--
作者：
Fernandes, Sofia;Sao-Jose, Carlos
双链DNA噬菌体采用孔蛋白-内溶素二联体作为裂解细菌宿主的不同策略的核心组分。在所谓的典型模型中，孔蛋白孔在裂解中起重要作用，因为它们为细胞质积累的内溶素通过细胞壁（CW）提供管道，在细胞壁中内溶素降解肽聚糖。认为一旦合成典型内溶素，其立即获得其完全活性构象，因此如果允许与CW接触，则具有有效切割肽聚糖的能力。然而，我们在这里表明，holin介导的细胞死亡可能需要完全敏感的细胞的典型内溶素的裂解作用，一个作用，显然是掩盖的关键功能的holin内溶素释放。我们证明，在某些条件下，枯草芽孢杆菌细胞能够从内部或外部抵消噬菌体SPP 1内溶素攻击CW的活性。这种能力在holin作用后或在模拟其膜去极化作用的试剂存在下丧失。我们观察到葡萄球菌内溶素的溶解活性和膜质子动力之间存在类似的关系。这些研究结果可能的影响，在开发的内溶酶作为酶进行了讨论。
Double-strand DNA bacteriophages employ the holin-endolysin dyad as core components of different strategies to lyse bacterial hosts. In the so-called canonical model the holin holes play an essential role in lysis as they provide a conduit for passage of the cytoplasm-accumulated endolysin to the cell wall (CW), where it degrades the peptidoglycan. It is considered that once synthesized canonical endolysins immediately acquire their fully active conformation, having thus the capacity to efficiently cleave the peptidoglycan if contact to the CW is allowed. We show here however that holin-mediated cell death may be required to fully sensitize cells to the lytic action of canonical endolysins, a role that is obviously masked by the key function of the holin in endolysin release. We demonstrate that in certain conditions Bacillus subtilis cells are capable of counteracting the activity of the phage SPP1 endolysin attacking the CW either from within or from without. This capacity is lost after holin action or in presence of agents that mimic its membrane-depolarizing role. We have observed a similar relationship between lytic activity and membrane proton motive force for a staphylococcal endolysin. The possible implications of these findings in the exploitation of endolysins as enzybiotics are discussed.