Architecture and Principle of Formation of the Baseplate of Bacteriophage T4

噬菌体T4底板的结构和形成原理

基本信息

批准号：
10480178
负责人：
ARISAKA Fumio
金额：
$ 4.93万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

Tail lysozyme, gp5, is a structurally essential component and possesses lysozyme activity which locally digests peptidoglycan of the host E.coli upon infection so that the tail tube can reach the inner membrane. Cleavage of gp5 precursor takes place between Ser351 and Ala352 during processing. The C- terminal domain, however, stays as part of the complex and will be detached only upon infection. We have demonstrated that the C-terminal domain is present in both tails and the virion. It was also shown that the tails in infedted cells also retain the C-terminal domain. Very recently, Shuji Kanamaruwho is a post-doctoral fellow at Purdue in Prof. Michael G.Rossmann's lab succeeded in determining the phase of diffractions from the crystal of gp5-gp27 hetero-hexamer. The structure of the complex is now being solved, but it already revealed the slender C-terminal triple beta-helix that makes gp5 a trimer. Another structure to be solved in this project is the initiation complex of the wedge of the baseplate, gp10-gp11 complex. It is considered to constitute the tail pins at the vertices of the hexagonal baseplate, which protrude from the bottom of the baseplate. Based on SDS-PAGE and Edman degradation of the complex and also analytical ultracentrifugation, it was shown that the complex is a hetero-hexamer with the subunit composition of (gp10)_3(gp11)_3. Crystal of the complex suitable for X-ray analysis has been recently been obtained which awaits the phase determination. As the third target protein for crystallization, gp15, the tail completion protein, was also overexpressed and crystallized. It forms a homo-hexamer and it is likely to form the last annulus of the tube ring. Efforts is being made to obtain larger crystals suitable for X-ray diffraction.

尾溶菌酶GP5是一种结构上必不可少的成分，具有溶菌酶活性，在感染后局部消化宿主大肠杆菌的肽聚糖，因此尾管可以到达内膜。 GP5前体的切割发生在处理过程中Ser351和Ala352之间。然而，C末端结构域保留为复合物的一部分，仅在感染后才能分离。我们已经证明了C末端结构域都存在于尾部和病毒座中。还表明，注射细胞中的尾巴也保留了C末端结构域。最近，Shuji Kanamaruwho是Michael G.Rossmann教授的Purdue的博士后研究员，成功地确定了从GP5-GP27 Hetero Hetero-Hexamer的晶体中确定衍射阶段。现在已经解决了该复合物的结构，但是它已经揭示了使GP5成为三聚体的细长C端三重β-螺旋。该项目中要解决的另一个结构是底板楔形物GP10-GP11复合物的启动复合物。它被认为构成六角形底板顶点的尾销，该底板从底板的底部突出。基于复合物和分析性超速离心的SDS-PAGE和EDMAN降解，结果表明，该复合物是（GP10）_3（GP11）_3的亚基组成的异质杂种。最近已经获得了适合X射线分析的复合物的晶体，以等待相确定。作为结晶的第三个靶蛋白，尾部完成蛋白的GP15也过表达并结晶。它形成一个均匀的杂物，很可能形成了管子环的最后一个环。正在努力获得适合X射线衍射的较大晶体。