Unusual Aggregation of a Nonfunctional Tobacco Mosaic Virus Protein

Abstract
The nonfunctional virus protein isolated from plants infected with the PM2 strain of tobacco mosaic virus aggregates to form elongated, two-stranded, open helical structures, in marked contrast with functional tobacco mosaic virus protein which aggregates into rods. This unique type of aggregation may explain why the PM2 protein is unable to combine with viral nucleic acid to form stable infectious virus particles.