Huiskonen Juha T, de Haas Felix, Bubeck Doryen, Bamford Dennis H, Fuller Stephen D, Butcher Sarah J
Institute of Biotechnology and Department of Biological and Environmental Sciences, University of Helsinki, P.O. Box 65 (Viikinkaari 1), FIN-00014 Helsinki, Finland.
Structure. 2006 Jun;14(6):1039-48. doi: 10.1016/j.str.2006.03.018.
Bacteriophage phi6 is an enveloped dsRNA virus with a segmented genome. Phi6 specifically packages one copy of each of its three genome segments into a preassembled polymerase complex. This leads to expansion of the polymerase complex, minus and plus strand RNA synthesis, and assembly of the nucleocapsid. The phi6 in vitro assembly and packaging system is a valuable model for dsRNA virus replication. The structure of the nucleocapsid at 7.5 A resolution presented here reveals the secondary structure of the two major capsid proteins. Asymmetric P1 dimers organize as an inner T = 1 shell, and P8 trimers organize as an outer T = 13 laevo shell. The organization of the P1 molecules in the unexpanded and expanded polymerase complex suggests that the expansion is accomplished by rigid body movements of the P1 monomers. This leads to exposure of new potential RNA binding surfaces to control the sequential packaging of the genome segments.
噬菌体phi6是一种具有分段基因组的包膜双链RNA病毒。Phi6将其三个基因组片段中的每一个的一个拷贝特异性地包装到一个预组装的聚合酶复合物中。这导致聚合酶复合物的扩张、负链和正链RNA的合成以及核衣壳的组装。phi6体外组装和包装系统是双链RNA病毒复制的一个有价值的模型。这里展示的分辨率为7.5埃的核衣壳结构揭示了两种主要衣壳蛋白的二级结构。不对称的P1二聚体组织成一个内部T = 1壳层，P8三聚体组织成一个外部T = 13左旋壳层。未扩张和扩张的聚合酶复合物中P1分子的组织方式表明，扩张是通过P1单体的刚体运动完成的。这导致新的潜在RNA结合表面暴露，以控制基因组片段的顺序包装。
