Singh Pratibha, Indi Shantinath S, Savithri Handanahal S
Department of Biochemistry, Indian Institute of Science, Bangalore, India.
Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India.
PLoS One. 2014 Jun 11;9(6):e99370. doi: 10.1371/journal.pone.0099370. eCollection 2014.
Groundnut Bud Necrosis Virus (GBNV) is a tripartite ambisense RNA plant virus that belongs to serogroup IV of Tospovirus genus. Non-Structural protein-m (NSm), which functions as movement protein in tospoviruses, is encoded by the M RNA. In this communication, we demonstrate that despite the absence of any putative transmembrane domain, GBNV NSm associates with membranes when expressed in E. coli as well as in N. benthamiana. Incubation of refolded NSm with liposomes ranging in size from 200-250 nm resulted in changes in the secondary and tertiary structure of NSm. A similar behaviour was observed in the presence of anionic and zwitterionic detergents. Furthermore, the morphology of the liposomes was found to be modified in the presence of NSm. Deletion of coiled coil domain resulted in the inability of in planta expressed NSm to interact with membranes. Further, when the C-terminal coiled coil domain alone was expressed, it was found to be associated with membrane. These results demonstrate that NSm associates with membranes via the C-terminal coiled coil domain and such an association may be important for movement of viral RNA from cell to cell.
花生芽坏死病毒（GBNV）是一种三分体负义RNA植物病毒，属于番茄斑萎病毒属血清群IV。非结构蛋白m（NSm）在番茄斑萎病毒中起运动蛋白的作用，由M RNA编码。在本通讯中，我们证明，尽管没有任何假定的跨膜结构域，但GBNV NSm在大肠杆菌和本氏烟草中表达时会与膜结合。将复性的NSm与大小在200 - 250 nm之间的脂质体孵育会导致NSm的二级和三级结构发生变化。在阴离子和两性离子去污剂存在的情况下也观察到类似的行为。此外，发现脂质体的形态在NSm存在时会发生改变。卷曲螺旋结构域的缺失导致植物中表达的NSm无法与膜相互作用。此外，当单独表达C端卷曲螺旋结构域时，发现它与膜相关。这些结果表明，NSm通过C端卷曲螺旋结构域与膜结合，这种结合可能对病毒RNA在细胞间的移动很重要。
