Paatero A O, Mindich L, Bamford D H
Department of Biosciences, Biocenter, FIN-00014, University of Helsinki, Finland.
J Virol. 1998 Dec;72(12):10058-65. doi: 10.1128/JVI.72.12.10058-10065.1998.
Bacteriophage phi6 is a complex enveloped double-stranded RNA virus with a segmented genome and replication strategy quite similar to that of the Reoviridae. An in vitro packaging and replication system using purified components is available. The positive-polarity genomic segments are translocated into a preformed polymerase complex (procapsid) particle. This particle is composed of four proteins: the shell-forming protein P1, the RNA polymerase P2, and two proteins active in packaging. Protein P7 is involved in stable packaging, and protein P4 is a homomultimeric potent nucleoside triphosphatase that provides the energy for the RNA translocation event. In this investigation, we used mutational analysis to study P4 multimerization and assembly. P4 is assembled onto a preformed particle containing proteins P2 and P7 in addition to P1. Only simultaneous production of P1 and P4 in the same cell leads to P4 assembly on P1 alone, whereas the P1 shell is incompetent for accepting P4 if produced separately. The C-terminal part of P4 is essential for particle assembly but not for multimerization or enzymatic activity. Altering the P4 nucleoside triphosphate binding site destroys the ability to form multimers.
噬菌体phi6是一种复杂的包膜双链RNA病毒，其基因组呈节段状，复制策略与呼肠孤病毒科非常相似。有一种使用纯化成分的体外包装和复制系统。正链基因组节段被转运到一个预先形成的聚合酶复合物（原衣壳）颗粒中。这个颗粒由四种蛋白质组成：形成外壳的蛋白质P1、RNA聚合酶P2以及两种在包装过程中起作用的蛋白质。蛋白质P7参与稳定包装，蛋白质P4是一种同多聚体强效核苷三磷酸酶，为RNA转运事件提供能量。在本研究中，我们使用突变分析来研究P4的多聚化和组装。除了P1之外，P4还被组装到一个预先形成的含有蛋白质P2和P7的颗粒上。只有在同一细胞中同时产生P1和P4时，P4才会单独在P1上组装，而如果P1外壳单独产生，则无法接受P4。P4的C末端部分对于颗粒组装至关重要，但对于多聚化或酶活性并非如此。改变P4核苷三磷酸结合位点会破坏形成多聚体的能力。
