The mycobacteriophage Ms6 encodes a chaperone-like protein involved in the endolysin delivery to the peptidoglycan
The mycobacteriophage Ms6 encodes a chaperone-like protein involved in the endolysin delivery to the peptidoglycan
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DOI：
10.1111/j.1365-2958.2010.07239.x
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发表时间：
2010-08-01
影响因子：
3.6
通讯作者：
Pimentel, Madalena
中科院分区：
文献类型：
--
作者：
Catalao, Maria Joao;Gil, Filipa;Pimentel, Madalena
与大多数双链DNA噬菌体一样，Ms6分枝杆菌噬菌体使用holin-endolysin系统来裂解其宿主。除了内溶素（lysA）和holin （hol）基因外，Ms6还编码三种辅助的裂解蛋白。在这项研究中，我们研究了Gp1的裂解功能，它是由位于lysA上游的Gp1基因编码的。在没有Ms6 holin的情况下，LysA和Gp1共表达后，观察到大肠杆菌裂解。Gp1不属于holin类蛋白，我们提供的证据表明它与分子伴侣蛋白有几个共同的特征。我们发现Gp1与LysA相互作用，并且这种相互作用对于LysA递送到其目标是必要的。此外，PhoA融合表明，在耻垢分枝杆菌中，LysA在Gp1存在的情况下被输出到胞质外环境。我们还发现Gp1对于有效的垢垢分枝杆菌裂解是必要的，因为Ms6 Gp1的缺失会导致宿主裂解缺陷。我们提出Ms6内溶素递送到小鼠层是由Gp1（一种伴侣样蛋白）以一种不依赖于holin的方式协助的。
Like most double-stranded (ds) DNA phages, mycobacteriophage Ms6 uses the holin-endolysin system to achieve lysis of its host. In addition to endolysin (lysA) and holin (hol) genes, Ms6 encodes three accessory lysis proteins. In this study we investigated the lysis function of Gp1, which is encoded by the gp1 gene that lies immediately upstream of lysA. Escherichia coli lysis was observed after coexpression of LysA and Gp1 in the absence of Ms6 holin. Gp1 does not belong to the holin class of proteins, and we provide evidence that it shares several characteristics with molecular chaperones. We show that Gp1 interacts with LysA, and that this interaction is necessary for LysA delivery to its target. In addition, PhoA fusions showed that, in Mycobacterium smegmatis, LysA is exported to the extracytoplasmic environment in the presence of Gp1. We also show that Gp1 is necessary for efficient M. smegmatis lysis, as Ms6 gp1 deletion results in host lysis defects. We propose that delivery of Ms6 endolysin to the murein layer is assisted by Gp1, a chaperone-like protein, in a holin-independent manner.