Strokovskaia L I, Grzela R, Chroboczek J, Kikhno I M, Chashchina L I, Solomko A P
Ukr Biokhim Zh (1999). 2007 Jan-Feb;79(1):85-93.
Genomes of some positive-strand RNA viruses do not contain cap-structure, but instead their 5'-end is covalently linked to a viral protein called VPg. Complex formation between VPg and cellular translation initiation factors (eIFs) has been extensively studied in the context of the model of this complex involvement in virus mRNA translation initiation and cellular protein translation shut down in infected cells. The potato virus (PVY) VPg was expressed in bacterial and baculovirus systems in order to investigate its binding capacity to wheat eIF4E and its isoform. Both purified recombinant eIF4E and eIF(iso)4E were identified in vitro as binding partners of the purified recombinant VPg by using affinity chromatography, as well in vivo by coexpressing of recombinant VPg and eIFs in insect cells with following complex purification using affinity chromatography. Besides it was shown that PVY VPg also formed a complex with endogenous insect eIF4E in vivo. PVY VPg interaction with eIF4E of wheat (non permissive plant for PVY), and also with so evolutionary distant partner as insect eIF4E suggests the conservation of general structural features of eIF4E implicated in the formation of the complex with VPg.
一些正链RNA病毒的基因组不包含帽结构，而是其5'端与一种名为VPg的病毒蛋白共价连接。在该复合物参与病毒mRNA翻译起始以及感染细胞中细胞蛋白翻译关闭的模型背景下，已对VPg与细胞翻译起始因子（eIFs）之间的复合物形成进行了广泛研究。为了研究马铃薯病毒（PVY）VPg与小麦eIF4E及其异构体的结合能力，在细菌和杆状病毒系统中表达了PVY VPg。通过亲和层析在体外鉴定纯化的重组eIF4E和eIF（iso）4E均为纯化的重组VPg的结合伴侣，在体内通过在昆虫细胞中共表达重组VPg和eIFs并随后使用亲和层析进行复合物纯化也得到了相同结果。此外，研究表明PVY VPg在体内也与昆虫内源性eIF4E形成复合物。PVY VPg与小麦（PVY的非寄主植物）的eIF4E相互作用，以及与进化上距离遥远的昆虫eIF4E相互作用，表明参与与VPg形成复合物的eIF4E的一般结构特征具有保守性。
