Phage T5 straight tail fiber is a multifunctional protein acting as a tape measure and carrying fusogenic and muralytic activities
Phage T5 straight tail fiber is a multifunctional protein acting as a tape measure and carrying fusogenic and muralytic activities
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DOI：
10.1074/jbc.m800052200
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发表时间：
2008-05-16
影响因子：
4.8
通讯作者：
Letellier, Lucienne
中科院分区：
文献类型：
--
作者：
Boulanger, Pascale;Jacquot, Pierre;Letellier, Lucienne
我们报告了Pb 2的生物信息学和功能特性，Pb 2是一种121 kDa的多聚体蛋白，形成噬菌体T5直纤维，并参与DNA转移到宿主中。预测Pb 2由三个结构域组成。区域I（残基1-1030）主要以卷曲螺旋的形式组织，并且具有卷尺蛋白的特征。区域II（残基1030-1076）含有两个α-螺旋跨膜区段。区域III（残基1135-1148）包括金属肽酶基序。表达并纯化截短形式的Pb 2（Pb 2-Cterm，残基964-1148）。Pb 2-Cterm与融合膜多肽具有共同的特征。它形成寡聚体结构并插入脂质体中，引发它们的融合。Pb 2-Cterm引起大肠杆菌细胞释放β-半乳糖苷酶和体外肽聚糖水解。基于这些多功能的特性，我们提出，结合T5噬菌体的受体触发大的构象变化，铅2。盘绕的线圈区域将用作用于触发头-尾连接器的打开的传感器。C-末端区域将进入宿主包膜，允许肽聚糖的局部降解和通过两个膜的融合形成DNA孔。
We report a bioinformatic and functional characterization of Pb2, a 121-kDa multimeric protein that forms phage T5 straight fiber and is implicated in DNA transfer into the host. Pb2 was predicted to consist of three domains. Region I ( residues 1-1030) was mainly organized in coiled coil and shared features of tape measure proteins. Region II ( residues 1030-1076) contained two alpha-helical transmembrane segments. Region III ( residues 1135-1148) included a metallopeptidase motif. A truncated version of Pb2 (Pb2-Cterm, residues 964-1148) was expressed and purified. Pb2-Cterm shared common features with fusogenic membrane polypeptides. It formed oligomeric structures and inserted into liposomes triggering their fusion. Pb2-Cterm caused beta-galactosidase release from Escherichia coli cells and in vitro peptidoglycan hydrolysis. Based on these multifunctional properties, we propose that binding of phage T5 to its receptor triggers large conformational changes in Pb2. The coiled coil region would serve as a sensor for triggering the opening of the head-tail connector. The C-terminal region would gain access to the host envelope, permitting the local degradation of the peptidoglycan and the formation of the DNA pore by fusion of the two membranes.