2015/12/18

Highest resolution structure of a flexuous filamentous plant virus

Flexible filamentous viruses are eukaryotic RNA viruses and economically important plant pathogens. Their viral particles contain several hundred copies of a helically arrayed coat protein (CP) protecting a (+)ssRNA. A research team from CICbioGUNE has described the structure of Pepino mosaic virus (PepMV) at 3.9 Å resolution by high-resolution electron cryo-electron microscopy. The work published in eLife journal has been carried out in collaboration with a research group at CEBAS-CSIC. The results allow modeling of the CP and its interactions with viral RNA. Surprisingly, the overall fold of PepMV CP resembles that of nucleoproteins (NPs) from the genus Phlebovirus (family Bunyaviridae), a group of enveloped (-)ssRNA animal viruses. The main difference between potexvirus CP and phlebovirus NP is in their C-terminal extensions, which appear to determine the characteristics of the distinct multimeric assemblies- a flexuous, helical rod or a loose ribonucleoprotein (RNP). The homology suggests gene transfer between eukaryotic (+) plant viruses and (-)ssRNA animal viruses.