Melting of viral RNA by coat protein: assembly strategies for elongated plant viruses.
The coat proteins of two rod-shaped plant viruses, papaya mosaic virus (PMV) and tobacco mosaic virus (TMV), have been tested for RNA melting activity. Under reconstitution conditions, PMV protein melts RNA in a noncooperative fashion. This activity is aspecific and is inhibited by low concentrations of NaCl as is virus reconstitution. TMV protein does not melt RNA either in the absence of NaCl or under reconstitution conditions at moderate ionic strength levels. The results suggest that elongated plant viruses have evolved at least two different assembly strategies in order to satisfy the requirement that the RNA within these viruses be in a melted configuration.
Erickson
J W
JW
Department of Plant Sciences, The University of Western Ontario, London, Ontario, Canada.
Bancroft
J B
JB