Bacteriophage T5 structure reveals similarities with HK97 and T4 suggesting evolutionary relationships
Bacteriophage T5 structure reveals similarities with HK97 and T4 suggesting evolutionary relationships
复制标题
DOI：
10.1016/j.jmb.2006.06.081
复制
发表时间：
2006-09-01
影响因子：
5.6
通讯作者：
Conway, J. F.
中科院分区：
文献类型：
--
作者：
Effantin, G.;Boulanger, P.;Conway, J. F.
病毒之间的进化关系可能被蛋白质序列所掩盖，但却被结构所掩盖。通过冷冻电子显微镜和蛋白质序列分析对噬菌体T5进行分析，发现与HK97和T4相似，表明这种连接是镶嵌的。T5衣壳与HK97衣壳蛋白折叠一致，但具有不同的几何形状，在每个二十面体小面上包含三个额外的六角体。与HK97类似，T5主要衣壳蛋白有一个N-末端延伸，即成熟衣壳中缺失的Delta结构域，通过与HK97类似，T5主要衣壳蛋白可能具有组装或支架结构域的功能。与HK97一样，这个三角洲区域被预测为主要卷曲的线圈，但与较大的衣壳相关联，其长度类似于70%。因此，衣壳架构似乎很可能是由Delta域指定的。与HK97不同的是，T5衣壳与每个六聚体中心的装饰蛋白结合在一起，类似于噬菌体T4的“临时”蛋白，这表明这些分子具有共同的作用。尾管具有不同寻常的三聚体对称性，这可能有助于独特的两阶段DNA喷射过程，并在尾部纤维附着的圆盘上连接尾端。噬菌体T5体现的这一耐人寻味的特征组合提供了对病毒组装、亚单位功能和相关病毒之间进化联系的洞察。(C)2006爱思唯尔有限公司。保留所有权利。
Evolutionary relationships between viruses may be obscure by protein sequence but unmasked by structure. Analysis of bacteriophage T5 by cryoelectron microscopy and protein sequence analysis reveals analogies with HK97 and T4 that suggest a mosaic of such connections. The T5 capsid is consistent with the HK97 capsid protein fold but has a different geometry, incorporating three additional hexamers on each icosahedral facet. Similarly to HK97, the T5 major capsid protein has an N-terminal extension, or Delta-domain that is missing in the mature capsid, and by analogy with HK97, may function as an assembly or scaffold domain. This Delta-domain is predicted to be largely coiled-coil, as for that of HK97, but is similar to 70% longer correlating with the larger capsid. Thus, capsid architecture appears likely to be specified by the Delta-domain. Unlike HK97, the T5 capsid binds a decoration protein in the center of each hexamer similarly to the "hoc" protein of phage T4, suggesting a common role for these molecules. The tail-tube has unusual trimeric symmetry that may aid in the unique two-stage DNA-ejection process, and joins the tail-tip at a disk where tail fibers attach. This intriguing mix of characteristics embodied by phage T5 offers insights into virus assembly, subunit function, and the evolutionary connections between related viruses. (c) 2006 Elsevier Ltd. All rights reserved.